External frost stat is in action or not doing anything?

[Jurgenjay]

Hi,

I have an external frost stat which I am not sure if it is in use or not. I had an electrician opened it and checked it, he said it is live. But he is not sure if it is in action or not....
I took a photo, could anyone confirm as the position it is, is this frost stat in action i.e. will protect boiler if temperature drops to some degree? If yes, what temperature it is set?

Thank you!

 

[John.g]

Measure or estimate the ambient temperature at the stat then just turn the dial slowly clockwise or anti clockwise until you hear a click, then note what reference mark, if any the temp setting on the dial that's closest to your measured temperature. (there seems to be a reference mark opposite 20C on the dial but very unlikely its set to this).
It should be set to 5C IMO.

Ensure boiler off before turning it up to check if boiler restarts, surprising the electrician didn't do this.

 

[Jurgenjay]

Measure or estimate the ambient temperature at the stat then just turn the dial slowly clockwise or anti clockwise until you hear a click, then note what reference mark, if any the temp setting on the dial that's closest to your measured temperature. (there seems to be a reference mark opposite 20C on the dial but very unlikely its set to this).
It should be set to 5C IMO.

Ensure boiler off before turning it up to check if boiler restarts, surprising the electrician didn't do this.

Thank you! Last night this Forum was down & could not open anymore....
Did you try to show me how to set the frost protection temperature? I am not sure about it.
Yes, I heard it should be set to 5C.
From the photo, are you able to see what temperature it is set to?

 

[John.g]

No, I can't really see from the photo where it's set to, its set to ~ 20C, if the REFERENCE MARK is where I am showing it with the arrow but as I said this is unlikely and why I suggest getting a household thermometer and measuring the (garage) ambient temperature close to the frost stat, then turn the dial clockwise/anticlockwise slowly until you hear a click, post a photo again when you hear/identify this.

 

[Jurgenjay]

No, I can't really see from the photo where it's set to, its set to ~ 20C, if the REFERENCE MARK is where I am showing it with the arrow but as I said this is unlikely and why I suggest getting a household thermometer and measuring the (garage) ambient temperature close to the frost stat, then turn the dial clockwise/anticlockwise slowly until you hear a click, post a photo again when you hear/identify this.

Hi John, Thank you again for your reply!

I just checked and turned the dial anti-clockwise, when I heard the click I stopped and took the photo(the green line & question mark is what you meant REFERENCE MARK, right?)---attached photo1;
The photo 2 is the garage temperature I just measured for where the boiler and frost stat locate;
The photo 3 is the original (without turning) position----At this position you cannot turn the dial clockwise anymore, it is to the end & stuck there----can only turn anti-clockwise.
As you can see from photo 1 and photo3, the REFERENCE MARK position is different now.

Also, when I heard the click---as per photo1 position, the boiler started to fire, burner light (green light) was on, and blue light was on, I went upstairs to see the zone valve for hot water opened & the pump made noise!

But I heard the external frost stat normally is wired to heating not hot water? Is my system correct?

Thanks!

 

[Gasmk1]

The arrow should be straight up the defence in the lager tooth sharp at top behind dial

 

[Jurgenjay]

The arrow should be straight up the defence in the lager tooth sharp at top behind dial

Thank you!
Did you mean the arrow (above"5") position should be straight up like attached photo? I marked a down-arrow on the wall, so is that the line should the arrow on the stat face up to?

 

[John.g]

The arrow should be straight up the defence in the lager tooth sharp at top behind dial

The 12 oclock position would seem normal all right.
The measured temperature is 12.5C and (photo1) so a setting of 8.5C which closed the contactsmeans that the stat has a offset (hysteresis) of 4C, if this is correct then the stat should be set at "2" or where it originally was which will close the contacts at approx 5C??.

 

[John.g]

Thank you!
Did you mean the arrow (above"5") position should be straight up like attached photo? I marked a down-arrow on the wall, so is that the line should the arrow on the stat face up to?

Yes, more or less correct, but a setting of 8.5C equals to your measured temperature of 12.5C so maybe repeat your test and if the same I would set the stat almost fully clockwise to its original setting of "2" which means that the stat will operate when the temperature is 5C?.

 

[Jurgenjay]

The 12 oclock position would seem normal all right.
The measured temperature is 12.5C and (photo1) so a setting of 8.5C which closed the contactsmeans that the stat has a offset (hysteresis) of 4C, if this is correct then the stat should be set at "2" or where it originally was which will close the contacts at approx 5C??.

The arrow straight up---if this means 5C then the original position(photo3) it means 0C?
My installer's boss who told me the installer(had left the boss) said"he had disconnected the external frost stat", if so, then the original position(0C?) means the frost stat is not in use?
Until today I turned the dial anti-clockwise and heard the click---which is photo1 position: the boiler started to fire, zone valve for hot water opened, green and blue light were on.
So at photo 1 position, the frost stat is in action? ---but today the garage is 12.5C which is too high for frost protection temperature?

 

[Jurgenjay]

Yes, more or less correct, but a setting of 8.5C equals to your measured temperature of 12.5C so maybe repeat your test and if the same I would set the stat almost fully clockwise to its original setting of "2" which means that the stat will operate when the temperature is 5C?.

Hi John, please see my earlier reply.
almost fully clockwise"2"---it might meant by the installer that "was disconnected"?

 

[John.g]

No, not at all, it just means that the stat will operate theoretically when the garage temperature falls to 2C that the stat will operate, you can't turn off a stat. but because the stat operated at a setting of 8.5C when the actual measured temperature is 12.5C then a setting of 5C will (probably) mean that the stat will operate at 9C which is too high,so suggest setting it to 2C which means it will operate at a higer temperature of around 5/6C.

To ensure that it's connected correctly you might turn off the HW and CH zones and carry out your test again, it should then fire up the boiler again.

 

[Jurgenjay]

No, not at all, it just means that the stat will operate theoretically when the garage temperature falls to 2C that the stat will operate, you can't turn off a stat. but because the stat operated at a setting of 8.5C when the actual measured temperature is 12.5C then a setting of 5C will (probably) mean that the stat will operate at 9C which is too high,so suggest setting it to 2C which means it will operate at a higer temperature of around 5/6C.

To ensure that it's connected correctly you might turn off the HW and CH zones and carry out your test again, it should then fire up the boiler again.

Thanks for letting me know the stat cannot be turned off! The installer(left the job) told his boss he disconnected the frost stat which now seems a lie to his boss (his boss does not know it is connected or disconnected hence I am asking here)

"the stat operated at a setting of 8.5C"---This is just the position when it clicked today, right? If so, everyday it could be at different position? As everyday temperature can be different? e.g. cold or warm days.

When the click happened, the boiler started to fire, the zone valve for hot water opened, green and blue light were on.
How do I turn off the zone valves for HW and CH?

 

[John.g]

""the stat operated at a setting of 8.5C"---This is just the position when it clicked today, right? If so, everyday it could be at different position? As everyday temperature can be different? e.g. cold or warm days.
It doesn't matter what the garage temperature is, if you have the stat set to operate at 5C then the garage temperature will have to fall to 5C before the boiler fires up, when the temperature reaches ~ 8/9C, the boiler will stop firing. You deliberately increased the setpoint to test the stat operation only.
"
You should or may have HW and CH selections on your programmer where you can set the times that you want them off and on, something like this one.

 

[Jurgenjay]

""the stat operated at a setting of 8.5C"---This is just the position when it clicked today, right? If so, everyday it could be at different position? As everyday temperature can be different? e.g. cold or warm days.
It doesn't matter what the garage temperature is, if you have the stat set to operate at 5C then the garage temperature will have to fall to 5C before the boiler fires up, when the temperature reaches ~ 8/9C, the boiler will stop firing. You deliberately increased the setpoint to test the stat operation only.
"
You should or may have HW and CH selections on your programmer where you can set the times that you want them off and on, something like this one.

On thread #5, photo 3 that is what the original position, you said that was set as 2C, right?

But you said suggest setting it to 2C which means it will operate at a higher temperature of around 5/6C.===why set it at 2C & will operate at a higher temperature of around 5/6C?
Why there's 4C difference?

I have the attached programmer, is this what you meant? I use this to set the timing for HW and CH start and finish time.

Thank you!

 

[John.g]

There is a difference of 4C because you discovered that yourself when the stat operated at a setting of 8.5C when the actual measured temperature was 12.5C , (12.5-8.5 = 4). All thermostats will have some difference between the setting temperature and the measured temperature, 4C might be a bit on the high side but you can compensate by making the setpoint 4C lower, in this case if you require the stat to operate at 5/6C you set it to 2C (6-4 = 2).

Re programmer, yes, that's it, so if you ensure both CH and HW Off then the boiler should still fire when you test it by increasing the frost stat setting until it clicks on. After testing, return it again to 2C.

 

[Jurgenjay]

There is a difference of 4C because you discovered that yourself when the stat operated at a setting of 8.5C when the actual measured temperature was 12.5C , (12.5-8.5 = 4). All thermostats will have some difference between the setting temperature and the measured temperature, 4C might be a bit on the high side but you can compensate by making the setpoint 4C lower, in this case if you require the stat to operate at 5/6C you set it to 2C (6-4 = 2).

Re programmer, yes, that's it, so if you ensure both CH and HW Off then the boiler should still fire when you test it by increasing the frost stat setting until it clicks on. After testing, return it again to 2C.

Yes, this afternoon I turned the dial anti-clockwise and when heard the click, I stopped, so the photo1 is the position as it was: 8.5C: the boiler started to fire, zone valve for hot water opened, green and blue light were on.
You mean to do this test again to obtain another setting temperature setting C or for what to do another test?
After testing, I turn it back to full clockwise i.e. 2C?

When you said setting frost stat at 2C, i.e. roughly the ambient temperature is 6C----this looks making sense for the case happened on 21st of January which the morning at 8:35am outside temperature was -6°C, and the garage (where my boiler is locates) temperature was 6.6°C, at the time, my boiler started to fire (outside of programmer setting period), zone valve for hot water opened, this lasted nearly 4 hours till 12:15pm.
So all this could be caused by the external frost stat triggered the boiler to start the frost protection function, right?

 

[John.g]

Don't think you need to repeat the test as the boiler fired up outside the programmed times so OK. The problem with this type of frost stat is that it is measuring a "room" temperature, ie the garage which is only heated by any radiated heat loss from the boiler so takes hours to reach the frost stat cut out temp which can be 4 to 6C higher than its setpoint.
If you were/are quite happy with the boiler itself which monitors the water temperatures and will only fire for the very minimum time required to prevent the water freezing, then all that probably has to be done to disable the external frost stat is to remove one wire in the stat.

You had another thread where it showed the parameters for the internal frost protection which seemed perfect.

I would suggest getting back on to the "boss" and tell him that the external stat is not disconnected.

 

[John.g]

You said.....
Below is the manual of my boiler regarding Frost Protection：

"If the temperature within the boiler falls below 8°C the pump will run to circulate water and prevent the system freezing. If the temperature within the boiler falls below 5°C the boiler will fire periodically, bringing the boiler temperature up to 12°C to avoid the possibility of the system freezing. This process will be repeated until such time that the boiler temperature does not drop below 5°C."

This is the full explanation of the above.

If the temperature within the appliance falls below 8°C the pump will run to circulate water and prevent the system freezing. – If the temperature does not rise to 9°C within 30 minutes of the pump operating, the appliance will fire up. ▶ If the temperature within the appliance falls below 5°C the appliance will fire immediately, bringing the appliance temperature up to 12°C to avoid the possibility of the appliance freezing. ▶ This process will be repeated until such time that the appliance temperature does not drop below 8°C."

 

[Jurgenjay]

Don't think you need to repeat the test as the boiler fired up outside the programmed times so OK. The problem with this type of frost stat is that it is measuring a "room" temperature, ie the garage which is only heated by any radiated heat loss from the boiler so takes hours to reach the frost stat cut out temp which can be 4 to 6C higher than its setpoint.
If you were/are quite happy with the boiler itself which monitors the water temperatures and will only fire for the very minimum time required to prevent the water freezing, then all that probably has to be done to disable the external frost stat is to remove one wire in the stat.

You had another thread where it showed the parameters for the internal frost protection which seemed perfect.

I would suggest getting back on to the "boss" and tell him that the external stat is not disconnected.

Hi John,
Thank you so much for your input throughout this thread! I got more useful information from you---on this website forum!
I should got all those answers from the gas engineer boss/team as they installed the boiler and all system, but the boss did not know the boiler/built-in frost protection/external frost stat/ zone valves how they work/should work etc. which forced me had to ask online! What a sad thing.....

As you suggested, I may need to get the external frost stat disconnected as it may conflict with the built-in frost protection?
I don't know how other houses do when they install a new boiler system i.e. get rid of the old external frost stat as nowadays new boiler normally has built-in frost protection already?

 

[Jurgenjay]

You said.....
Below is the manual of my boiler regarding Frost Protection：

"If the temperature within the boiler falls below 8°C the pump will run to circulate water and prevent the system freezing. If the temperature within the boiler falls below 5°C the boiler will fire periodically, bringing the boiler temperature up to 12°C to avoid the possibility of the system freezing. This process will be repeated until such time that the boiler temperature does not drop below 5°C."

This is the full explanation of the above.

If the temperature within the appliance falls below 8°C the pump will run to circulate water and prevent the system freezing. – If the temperature does not rise to 9°C within 30 minutes of the pump operating, the appliance will fire up. ▶ If the temperature within the appliance falls below 5°C the appliance will fire immediately, bringing the appliance temperature up to 12°C to avoid the possibility of the appliance freezing. ▶ This process will be repeated until such time that the appliance temperature does not drop below 8°C."

Thank you again John!
i am a bit curious that the way of the built-in frost protection function seems never in action...
In middle of Jan, especially on 21st of Jan (outside -6°C ) which were cold and minus 0°C, but I never noticed the pump circulating or boiler started fire. I measured on 21st of Jan the garage temperature was 6.6 °C---maybe the boiler water temperature was still higher than 8 °C thus frost protection still not in action?

As mentioned earlier, on 21st of January in the morning at 8:35am outside temperature was -6°C, and the garage (where my boiler is locates) temperature was 6.6°C, at the time, my boiler started to fire (outside of programmer setting period), zone valve for hot water opened, this lasted nearly 4 hours till 12:15pm.
All this could be caused by the external frost stat triggered the boiler to start the frost protection function, right?
So it seems external frost stat worked(not sure yet)? But built-in frost protection not?

 

[John.g]

The internal frost protection will only operate if the boiler water temperature falls below 8C (that's my interpretation of "the temperature within the appliance") so if the boiler was programmed on until say 2200 hrs each night then the boiler water temperature may well be ~ 50/55C at shutdown and it will take it a long time to fall to 8C, it may take more time to do this than the interval between night shut down and next morning start time, if so, then the external stat will have operated as its measuring the garage air temperature and it has fallen to ~ 6/7C.
You could look at the boiler water temperature a few times (if available on the boiler menu) during the next cold night and compare it with the garage temperature.
Remember, on Jan21st, the outside temperature was -6.0C and the garage temperature was +6.6C so the external frost stat operated more or less which now know will happen with a setting of ~ 2C (due to the 4C offset) and there is no way IMO that the boiler water temperature would have fallen to 8C (from 50/55C) during that period.

For interest, was the HW very hot that morning as the HW zone valve is opened during external frost protection period(s), I would have expected it to reach the boiler water cut out temp of 70C or whatever you have it set to.

 

[Jurgenjay]

The internal frost protection will only operate if the boiler water temperature falls below 8C (that's my interpretation of "the temperature within the appliance") so if the boiler was programmed on until say 2200 hrs each night then the boiler water temperature may well be ~ 50/55C at shutdown and it will take it a long time to fall to 8C, it may take more time to do this than the interval between night shut down and next morning start time, if so, then the external stat will have operated as its measuring the garage air temperature and it has fallen to ~ 6/7C.
You could look at the boiler water temperature a few times (if available on the boiler menu) during the next cold night and compare it with the garage temperature.
Remember, on Jan21st, the outside temperature was -6.0C and the garage temperature was +6.6C so the external frost stat operated more or less which now know will happen with a setting of ~ 2C (due to the 4C offset) and there is no way IMO that the boiler water temperature would have fallen to 8C (from 50/55C) during that period.

For interest, was the HW very hot that morning as the HW zone valve is opened during external frost protection period(s), I would have expected it to reach the boiler water cut out temp of 70C or whatever you have it set to.

Thanks a lot again John!
Your analysis regarding how the built-in frost protection works and external frost stat works look very reasonable!
This can explains why I never seen internal frost protection worked as you said, the boiler water temperature will take a long time to drop below 8C.
For that coldest day--21st of Jan (I tracked the temperature those days) in the morning 8:35am, the boiler started to fire, should be because the garage temperature dropped at around 6.6C---this should trigger the external frost stat to demand boiler to fire. And until the garage air temperature reached 7.5C(I measured at the time) the boiler stopped firing and zone valve closed.

You are right again for the HW! I did not check that day(21st of Jan) morning HW temperature, but I did have a shower right after the HW programmer was on a long time, I could feel HW was very hot!

 

[SJB060685]

I haven’t read every above comment so forgive me if this has already been mentioned.
The idea of a frost stat is as you know to prevent water in the boiler/system from reaching freezing point. The problem is as John mentioned above the garage will take quite some time to satisfy the frost stat on cold days because the only energy heating that air space is standing heat losses from the boiler. Boilers have both a combustion efficiency and an appliance efficiency. If the standing heat losses from your boiler are low then it would take hours, maybe even never satisfy the frost stat on cold days due to the garage having high heat loss itself.
Now the frost stat should be wired in series with a clamp on low temperature pipe stat on the return to the boiler, which SHOULD open the CH zone valve to dump the heat. The return clamp on stat is usually set to about 20°c and when the return water reaches that temperature the stat contacts will open and cut power to the CH valve and in turn the boiler. Without this additional clamp on stat you will get constant cycling at the burner.
Remember the idea of this setup is to prevent the boiler from freezing, while using as little fuel as possible.

 

[Jurgenjay]

I haven’t read every above comment so forgive me if this has already been mentioned.
The idea of a frost stat is as you know to prevent water in the boiler/system from reaching freezing point. The problem is as John mentioned above the garage will take quite some time to satisfy the frost stat on cold days because the only energy heating that air space is standing heat losses from the boiler. Boilers have both a combustion efficiency and an appliance efficiency. If the standing heat losses from your boiler are low then it would take hours, maybe even never satisfy the frost stat on cold days due to the garage having high heat loss itself.
Now the frost stat should be wired in series with a clamp on low temperature pipe stat on the return to the boiler, which SHOULD open the CH zone valve to dump the heat. The return clamp on stat is usually set to about 20°c and when the return water reaches that temperature the stat contacts will open and cut power to the CH valve and in turn the boiler. Without this additional clamp on stat you will get constant cycling at the burner.
Remember the idea of this setup is to prevent the boiler from freezing, while using as little fuel as possible.

Thanks for your input!
The first part I now understand it & it explains on 21st of Jan(coldest day of those minus degree days) morning why my boiler stated to fire outside of programmer setting period and lasted nearly 4 hours!

The second part, there maybe another issue from my newly installed system: it seems my external frost stat is wired in series with HW instead of CH! i.e. on the morning of 21st of Jan, when the boiler fired, the zone valve for HW opened NOT zone valve for CH!

The pipe stat is like attached photos?

Also, now, another issue I don't know whether it is same for zone valve for HW: even if when HW programmer is on for a long time, say a few hours, the zone valve for HW never close! and the blue light always on! The burner light (green light) is off, then on, then off for every a couple of minutes.

 

[SJB060685]

A clamp on stat is more like the image furthest to the left.
The HW zone valve should close when the cylinder stat is satisfied. If the motorised valve isn’t closing it’s still getting a feed from somewhere. It could be a faulty cylinder stat or the cylinder stat isn’t connecting properly with the cylinder if it’s an open vented HW system?

 

[Jurgenjay]

A clamp on stat is more like the image furthest to the left.
The HW zone valve should close when the cylinder stat is satisfied. If the motorised valve isn’t closing it’s still getting a feed from somewhere. It could be a faulty cylinder stat or the cylinder stat isn’t connecting properly with the cylinder if it’s an open vented HW system?

Yes, I also learned that the zone valve for HW and zone valve for CH should both close if the cylinder stat and house setting temperature are satisfied, but only zone valve for CH closed when it reaches house setting temperature, but zone valve for HW NEVER close during programmer "on" period (when programmer setting time is off, then the zone valve for HW does close---so it this looks zone valve is no problem, right?)
My system is unvented cylinder system.

 

[John.g]

Does the HW zone valve close when HW programmed off?. if so maybe something as simple as the boiler temperature not set 5 to 10C higher than the cylinder stat, ie if cylinder stat set to 60C, boiler should be set to 65/70C.

 

[SJB060685]

It could be wired wrong, it could be a dodgy stat or not sitting on cylinder properly. A photo of the cylinder and stat would help.
John raises a good point as well. If the cylinder stat is set to 60°c then the boiler flow should be higher.

 

[Jurgenjay]

Does the HW zone valve close when HW programmed off?. if so maybe something as simple as the boiler temperature not set 5 to 10C higher than the cylinder stat, ie if cylinder stat set to 60C, boiler should be set to 65/70C.

HW zone valve indeed close when HW programmer is off.
But your comment does draw my attention: "the boiler temperature not set 5 to 10C higher than the cylinder stat, ie if cylinder stat set to 60C, boiler should be set to 65/70C."
Is this a must? Could you explain this theory?
I just checked my temperature settings:
Please see photo1 which is my boiler photo, that is central heating setting, right? according to photo 2 "setting temperature for your heating", I turned the knob to the position around 5 which is 74C;
My cylinder stat is set to close to 65C, maybe 60C, or 61C, or 62C, please see photo 3.
So based on your theory, my central heating temperature(74C) and cylinder stat temperature(60,1,2C) are correct?

 

[Jurgenjay]

It could be wired wrong, it could be a dodgy stat or not sitting on cylinder properly. A photo of the cylinder and stat would help.
John raises a good point as well. If the cylinder stat is set to 60°c then the boiler flow should be higher.

Please see attached photo of stat on cylinder and cylinder, if they are good to judge?
Please refer to my last reply to John that how I set the cylinder temperature and boiler heating temperature.

 

[SJB060685]

The theory revolves around the first law of thermodynamics. Basically if the water leaving your boiler is max 60°c then the maximum temperature the water in the cylinder could ever be is 60°c. You have the cylinder stat at 65°c which in my opinion is 5°c too high because if you’re in a hard water area this temperature can cause lime scale to form. Set the cylinder stat to 60°c and leave the boiler at about 70°c. Any higher and you start to lose any condensing

 

[John.g]

The divisions on the cylinder stat are extraordinary at 6.66C/division just to create more of a challenge when setting it?.

Anyway, to test the stat, just turn it down and see if the HW cylinder zone valve closes while programmed on.

 

[Jurgenjay]

The theory revolves around the first law of thermodynamics. Basically if the water leaving your boiler is max 60°c then the maximum temperature the water in the cylinder could ever be is 60°c. You have the cylinder stat at 65°c which in my opinion is 5°c too high because if you’re in a hard water area this temperature can cause lime scale to form. Set the cylinder stat to 60°c and leave the boiler at about 70°c. Any higher and you start to lose any condensing

Thank you for letting me know this theory!
My cylinder stat is not set as 65°c, it is about 60-65°c. It is because between 65°c---45°c the gap is 20°c, there are 3 gaps, so i set it between 65°c and the next mark.
The reason I set on that position (60-65°c )is because I learned that the hot water should be set over 60°c in order to kill legionella bacteria. (as attached picture)
So for my cylinder stat temperature, I should/could turn the heating setting knob smaller, say between 4-5 to make it around 71°c ?(this attached photo2)

 

[John.g]

That sound correct Jurgen but to check correct wiring, you might do the test I suggested in post #33.

 

[Jurgenjay]

The divisions on the cylinder stat are extraordinary at 6.66C/division just to create more of a challenge when setting it?.

Anyway, to test the stat, just turn it down and see if the HW cylinder zone valve closes while programmed on.

Exactly! Not sure why they designed and produced the stat like that!

Your solution to test the stat proved right! A few months ago, the very first time when we found the boiler was still firing even the programmer was off, the zone valve for hot water was opened, by chance, we turned the stat of the cylinder smaller, and saw the zone valve closed and boiler stopped, so at the time we could see the stat temperature setting seems working.
(then next time when it happened again: zone valve for hot water opened & boiler fired outside of programmer setting period, even if we turned the stat of cylinder smaller, boiler still continued to fire, so second time maybe zone valve issue.)

 

[SJB060685]

Yes legionella bacteria is killed off at 60°c. Yes set boiler control stat to that but no higher. The dew point for natural gas boilers starts at around 57°c, so your return water temperature needs to be that or lower, the lower the return temperature the greater the condensing. You also get greater condensing when the boiler is at part load but I won’t go into that now. If I was designing your system I would of done things a lot differently but that’s irrelevant now. As John says run his test to see what happens to the HW valve.

 

[SJB060685]

Depends on how it’s wired. If the frost stat by passes the cylinder stat it will hold the valve open,

 

[John.g]

Re cylinder stat, with HW programmed on, turn stat down and note what its setting is, (check zone valve closing), turn stat back up slowly to reopen the zone valve, note the setting then turn it back down again to close the zone valve, gain note the setting, there should be ~ 5/8C differential.

Also see if the cylinder stat is located above the coil return from the cylinder.

 

[Jurgenjay]

Re cylinder stat, with HW programmed on, turn stat down and note what its setting is, (check zone valve closing), turn stat back up slowly to reopen the zone valve, note the setting then turn it back down again to close the zone valve, gain note the setting, there should be ~ 5/8C differential.

Also see if the cylinder stat is located above the coil return from the cylinder.

I got your point for how to turn and note the temperatures. That will have 3 temperatures?
i.e. 1st temperature: turn down when zone valve closes; 2nd temperature: turn up when zone valve opens; 3rd turn down again to close the zone valve.
So three temperature notes---to test what? Sorry I don't understand this?

Also see if the cylinder stat is located above the coil return from the cylinder.---is attached photo good to see? (if not, I can take another one)

 

[Jurgenjay]

Yes legionella bacteria is killed off at 60°c. Yes set boiler control stat to that but no higher. The dew point for natural gas boilers starts at around 57°c, so your return water temperature needs to be that or lower, the lower the return temperature the greater the condensing. You also get greater condensing when the boiler is at part load but I won’t go into that now. If I was designing your system I would of done things a lot differently but that’s irrelevant now. As John says run his test to see what happens to the HW valve.

so I am going to turn the boiler temperature control smaller, something between level 4--5, about 71°c, or 70°c or 72°c.
My installed system has caused me so much trouble..... I wonder how you would design it! Anything could be better!
The worse thing is the boss/gas engineer of my system does NOT know any of those questions I raised here........

 

[Jurgenjay]

Depends on how it’s wired. If the frost stat by passes the cylinder stat it will hold the valve open,

Your this comment I think could explain for what happened in the morning on 21st of Jan when it was very cold, my boiler started to fire for 4 hours outside of the programmer setting time.

 

[SJB060685]

I would set the boiler control knob to 5 which is a flow temp of 74°c ish.
If I was designing your system I would of designed a low temperature system with a boiler with good modulation and PDHW (priority domestic hot water) on either weather compensation or load compensation, that depends on a few things There are lots of advantages to low temperature heating systems. Less fuel consumption, better condensing, greater levels of comfort and cleaner air due to lower convection currents, better for the environment and so on. It is alarming that the boss of the company who installed this system is not fully clued up.

 

[John.g]

I got your point for how to turn and note the temperatures. That will have 3 temperatures?
i.e. 1st temperature: turn down when zone valve closes; 2nd temperature: turn up when zone valve opens; 3rd turn down again to close the zone valve.
So three temperature notes---to test what? Sorry I don't understand this?

Also see if the cylinder stat is located above the coil return from the cylinder.---is attached photo good to see? (if not, I can take another one)

I just want to ensure that the valve closes, re opens and closes again and also to check the cylinder stat differential (hysteresis) temperature between cut in and cut out.
I think the cylinder stat is located above the coil return from your photo.

 

[Jurgenjay]

I would set the boiler control knob to 5 which is a flow temp of 74°c ish.
If I was designing your system I would of designed a low temperature system with a boiler with good modulation and PDHW (priority domestic hot water) on either weather compensation or load compensation, that depends on a few things There are lots of advantages to low temperature heating systems. Less fuel consumption, better condensing, greater levels of comfort and cleaner air due to lower convection currents, better for the environment and so on. It is alarming that the boss of the company who installed this system is not fully clued up.

Right now it is 74°c(according to photo2), please see attached photo1. The stat on cylinder is between 60°c--65°c, something around 61°c?
So based on your theory should be 10°c higher, I should turn the boiler heating setting to around 71°c? (Turn to level 4 direction).

Your design looks good! But it is late now....

The boss's name and company are registered on the Wocester Bosch boiler website, so I picked him who should know the boiler system in theory!
The actual installation was done by his team member who left him, the boss did the commission.
But since I moved in, LOTS of problems happened! I can list 10 big issues here....
Worse of all, he came and checked, but he could not understand where/why gone wrong, I had to spend plenty of time here to get consultancy! I learn from you guys and got clearer answers than the one I paid over 5K for the system!!

 

[SJB060685]

Yes leave at those settings you mentioned above. Note if the rads struggle to get to temperature during extreme weather you may need to increase the flow temperature knob a bit but all these things should be considered during design stage. I’m not a fan of Worcester boilers personally but your system is installed now.
Most of us engineers on here are happy to help if possible. Myself and John here are passionate about what we do and if we can help and educate a little we will.

 

[Jurgenjay]

I just want to ensure that the valve closes, re opens and closes again and also to check the cylinder stat differential (hysteresis) temperature between cut in and cut out.
I think the cylinder stat is located above the coil return from your photo.

Re cylinder stat, with HW programmed on, turn stat down and note what its setting is, (check zone valve closing), turn stat back up slowly to reopen the zone valve, note the setting then turn it back down again to close the zone valve, gain note the setting, there should be ~ 5/8C differential.

Also see if the cylinder stat is located above the coil return from the cylinder.

Hi John, following your advice I have tested the stat and noted down each time temperatures. Please see below:

Photo1: turned down stat till heard "click", the zone valve for hot water was closing. The temperature is around 48°C;
Photo2: Turned up stat till heard "click", the zone valve for hot water was opening. The temperature is around 58°C;
Photo3: turned down stat till heard "click", the zone valve for hot water was closing. The temperature is around 48°C;
Photo4: Turned up stat till heard "click", the zone valve for hot water was opening. The temperature is around 58°C;

So, these mean the cylinder stat is working with no issue?

Thank you!

 

[Jurgenjay]

Also see if the cylinder stat is located above the coil return from the cylinder.

Hi John,
Yesterday the photo maybe not clear, I have taken again for you to see if the cylinder stat is above coil return from the cylinder?
Thanks again!

 

[John.g]

Everything looks good to me

 

[Jurgenjay]

Everything looks good to me

Everything---You mean both "stat on cylinder" and "if the cylinder stat is above coil return from the cylinder" are good?

Do you know "only nit pick is combo / inlet valve not above cylinder but that’s only a real issue when servicing cylinder just needs to be drained"---if this is an issue?

Thanks!

 

[Jurgenjay]

Yes leave at those settings you mentioned above. Note if the rads struggle to get to temperature during extreme weather you may need to increase the flow temperature knob a bit but all these things should be considered during design stage. I’m not a fan of Worcester boilers personally but your system is installed now.
Most of us engineers on here are happy to help if possible. Myself and John here are passionate about what we do and if we can help and educate a little we will.

Many thanks!
Really appreciate your input and John's!
As said, I know more from you guys online then the so called gas engineer I paid thousands of pounds!

 

[SJB060685]

Many thanks!
Really appreciate your input and John's!
As said, I know more from you guys online then the so called gas engineer I paid thousands of pounds!

Just promise us you won’t have him/them return. It’s alarming someone who advertises this line of work doesn’t even know the basics. I would seek advice from another G3 installed engineer as well as it would appear the frost stat is by passing the cylinder stat and controlling the HW zone valve. I’m not convinced that’s legal, logic would say not but I’m not currently G3 certified.

 

[John.g]

Everything---You mean both "stat on cylinder" and "if the cylinder stat is above coil return from the cylinder" are good?

Do you know "only nit pick is combo / inlet valve not above cylinder but that’s only a real issue when servicing cylinder just needs to be drained"---if this is an issue?

Thanks!

Everything---You mean both "stat on cylinder" and "if the cylinder stat is above coil return from the cylinder" are good?

Do you know "only nit pick is combo / inlet valve not above cylinder but that’s only a real issue when servicing cylinder just needs to be drained"---if this is an issue?

Thanks!

Yes, the stat position and stat operation are fine. The combination valve is often/normally mounted low down, you don't need a step ladder then to service it?

 

[Jurgenjay]

Yes, the stat position and stat operation are fine. The combination valve is often/normally mounted low down, you don't need a step ladder then to service it?

Thanks John!

 

[Jurgenjay]

Just promise us you won’t have him/them return. It’s alarming someone who advertises this line of work doesn’t even know the basics. I would seek advice from another G3 installed engineer as well as it would appear the frost stat is by passing the cylinder stat and controlling the HW zone valve. I’m not convinced that’s legal, logic would say not but I’m not currently G3 certified.

Yes, you are right that something for sure is wrong with my HW control, i.e. zone valve for HW never closed & burner light is off/on every couple of minutes, blue light is always on, even if the programmer is on for a long time---as long as programmer is on.

And you help me more make decision that not to call him for the warranty---my new boiler only a few months installed, it is well in the warranty period, but what is the point calling him if he does NOT know how the boiler is working?!
How could he be Woecster Bosch registered engineer then??
And he has not given me unvented cylinder system installation certificate as he is not G3 qualified I just found out...

 

[SJB060685]

Providing the boiler has been installed to manufacturers instructions then Worcester themselves would send an engineer should there be a warranty call. It’s just disheartening when a customer puts their faith in a guy/firm and pays thousands in your case for a system less than ideal. The old saying “a good engineer is an engineer for life” holds true. Hopefully you can find someone more qualified in the future.

 

[Jurgenjay]

Providing the boiler has been installed to manufacturers instructions then Worcester themselves would send an engineer should there be a warranty call. It’s just disheartening when a customer puts their faith in a guy/firm and pays thousands in your case for a system less than ideal. The old saying “a good engineer is an engineer for life” holds true. Hopefully you can find someone more qualified in the future.

Wocester Bosch did send an engineer came to check and confirmed to me: There's nothing wrong with boiler itself, it is the control or wiring issue, you should call your installer....
Not only boiler, but also newly installed radiators not all hot (half hot, half warm or cold); underground pipes bursted; bathroom pipe bursted, radiator leaked etc. all problems were done by this same guy!

 

[SJB060685]

Jesus. He sounds more like a handyman than a certified heating engineer.

 

[Jurgenjay]

Jesus. He sounds more like a handyman than a certified heating engineer.

He is registered on Worcester Bosch website, and he is on Checktrade but no review since last year August (just by time finished my boiler system installation).
For the questions I raised here (you may search this site I raised a lot of questions) he could not answer or sort out, thus I had to try to find answers myself.
He had a team member who did the boiler installation but left him now, I am not sure whether this is the reason he does not know the boiler because all boiler installation works were done by someone else?

During the boiler installation and after it, the boiler leaked water in garage!
Then upstairs all new radiators leaked water which flooded the house;
then one individual radiator leaked again which could not stop the water which resulted in downstairs celling with water dropped;
then underground pipes bursted which resulted in newly fitted marble floor was hammered and dug a hole;
then bathroom pipe bursted which made newly decorated house celling been flooded;

I have to stop otherwise it could be a further long list to go.....

 

[SJB060685]

I hope you claimed off his insurance!?

 

[Jurgenjay]

I hope you claimed off his insurance!?

Thank you for this reminder!
I didn't know I could claim off his insurance?
I had photos of those leaks and damage, but I need to prove it was his fault? Or simply because he did all the installation he just should be responsible for those damage? And I need to prove the damage figures?
I may just be too naive or kind, he didn't take me serious, for example, the HW zone valve never closed issue, I texted him and called him many times, he was not answering...

 

[SJB060685]

I’m not too clued up on the legal side of things. I think @king of pipes may be able to advise there. If you have sufficient evidence and invoices for the repairs then I would definitely look further into it. No business wants to have a claim made against their insurance but it’s there for reasons just like this. We only ever had one claim made against us, which turned out to be a manufacturers fault and subsequently dropped against us. My concern is though does this person even have insurance? I’d imagine if he’s gas certified then he must do.

 

[Jurgenjay]

I’m not too clued up on the legal side of things. I think @king of pipes may be able to advise there. If you have sufficient evidence and invoices for the repairs then I would definitely look further into it. No business wants to have a claim made against their insurance but it’s there for reasons just like this. We only ever had one claim made against us, which turned out to be a manufacturers fault and subsequently dropped against us. My concern is though does this person even have insurance? I’d imagine if he’s gas certified then he must do.

I checked his Checktrade about his insurance: "Current: Verified 20/03/2020." So he has but verified 2 year ago?
If @king of pipes could provide some advice that would be great!

Many thanks for your advice & reminder and all! Very helpful!

 

[SJB060685]

I would never use a place like Checktrade etc to generate income, nor would I look in places like that for an installer. Generally speaking a good trades person doesn’t need to advertise, if their work is top quality word of mouth is all they need, apart from van sign writing. Give King a chance to respond. He’s a frequent contributor but you may not get a response until tomorrow. I believe his wife works in legal sector so any advice he gives is sound advise.

 

[Jurgenjay]

I would never use a place like Checktrade etc to generate income, nor would I look in places like that for an installer. Generally speaking a good trades person doesn’t need to advertise, if their work is top quality word of mouth is all they need, apart from van sign writing. Give King a chance to respond. He’s a frequent contributor but you may not get a response until tomorrow. I believe his wife works in legal sector so any advice he gives is sound advise.

I agree with you in terms of really good engineers do not need advertisement as they are very busy with recommended works already!
This so called engineer caused me so much trouble e.g. he cut downstairs hot water pipe and not come back to re-pipe it, leave downstairs toilet and utility no hot water for the whole winter! My 4 year little girl every time before meal refuses to wash hand as it is too cold so we have to take her upstairs....

I will look forward to @king of pipes help! As I can list 10 big issue like above mentioned one that caused by this engineer, but no clue how/what to do in what ways...

Thanks again mate! You are actually helping real engineers to get more jobs rather than this kind of cowboy do advertisement and take jobs that they are not competent to do!

 

[king of pipes]

Good morning Jurgenjay I have studied your posts and it's obvious that you have been treated terribly, unfortunately this seems to happen quite frequently with the shortage of good tradesmen and the ease that someone can set up as a so called installer , the sign of a good tradesmen is what he does when something does go wrong in this case it seems very little.
Now what are your options ? You could go down the small claims court route but it will be a lengthy drawn out process which alot of people don't have the stomache for and end up giving up.
You could complain to trading standards no reputable company want to be investigated by them as it will blacken their name,
The company you employed has a duty of care to carry out the work as agreed the job was either carried out by a subcontractor or now ex employee but the responsibility lies with the owner of that company.
Was a detailed estimate or quote provided stating what work was to be carried out ?
What is the relationship like between yourself and the company ? has it broken down and you are being ignored ?
The bottom line is do want this company in your property? you've had a bad experience and at best the work will be patched up and cause issues for you at a later date , legally you need to give him the opportunity to correct the work but it very rarely ends well as you have no confidence in him and he probably sees you as a irritation.
The best outcome would probably be to employ a reputable company to correct the poor installation and try to recover a percentage of the cost from the original company, it really comes down to whether you have the time and are willing to perdue this individual relentlessly it will take a long time with no guarantee of a good outcome. Regards kop 👍

 

[Jurgenjay]

Good morning Jurgenjay I have studied your posts and it's obvious that you have been treated terribly, unfortunately this seems to happen quite frequently with the shortage of good tradesmen and the ease that someone can set up as a so called installer , the sign of a good tradesmen is what he does when something does go wrong in this case it seems very little.
Now what are your options ? You could go down the small claims court route but it will be a lengthy drawn out process which alot of people don't have the stomache for and end up giving up.
You could complain to trading standards no reputable company want to be investigated by them as it will blacken their name,
The company you employed has a duty of care to carry out the work as agreed the job was either carried out by a subcontractor or now ex employee but the responsibility lies with the owner of that company.
Was a detailed estimate or quote provided stating what work was to be carried out ?
What is the relationship like between yourself and the company ? has it broken down and you are being ignored ?
The bottom line is do want this company in your property? you've had a bad experience and at best the work will be patched up and cause issues for you at a later date , legally you need to give him the opportunity to correct the work but it very rarely ends well as you have no confidence in him and he probably sees you as a irritation.
The best outcome would probably be to employ a reputable company to correct the poor installation and try to recover a percentage of the cost from the original company, it really comes down to whether you have the time and are willing to perdue this individual relentlessly it will take a long time with no guarantee of a good outcome. Regards kop 👍

Thank you very much King of Pipes for your reply!
I agree with you that this kind of situation happens quite frequently is because "shortage of good tradesmen and the ease that someone can set up as a so called installer".
This results in homeowners suffer and real good tradesmen have less jobs...
But worst of all is, no such an authority or institution in place to check the works done and judge how bad it is, you will have to, as you said, to sue the bad tradesman to court which will take time and end up giving up---this is the reason the bad job done happens frequently and bad tradesman are so common to be encountered.

I do have a detailed estimate or quote, now the thing is, all the works done have issues, radiators not all hot, radiators leaked, pipes bursted, boiler issues etc.

The relationship is tricky to say, as this tradesman is tricky, he never said "NO, I don't want to come or don't want to be responsible", but he just not pick the phone or rely messages, if you call him twice every day 5 days a week, he or his wife might call back once asked: what's going on?, then he said he has priority as old women no heating and no hot water, he has to take care of them first.---every time same excuse: old people no HW no CH.

He has been dragging the issues without trying to sort out, he is either : not willing to waste time on rectifying the issues (as I paid him all the money on the quote) or, he really does not know how to do the boiler.
Either way, it is really bad!