Vaillant boiler issues F28 on ecotec 430 not the normal culprit

[Navi Bhander]

Hi there,

I’m hoping someone can help the last 9 months of intermittent issues we’re having.

We live in a large house which is heated by 2 Vaillant ecotec plus 430 system boilers. They’re wired up together so will work at the same time.

They are used to supply underfloor heating downstairs, 300l megaflo and radiators upstairs.

There are valves controlling the flow to each one and one large pump that circulates the water.

The house is controlled by Honeywell’s evohome system, 2 controllers to be precise.

The issue we’re having is sometimes the boilers don’t fire up. F28 fault code. The gas company over a period of months came and checked, they were adamant there wasn’t a gas issue but the pressure was on the low side of normal, 16-19mb and fluctuated.

After months they upgraded the gas pipe from the main road to the house to a 63mm pipe and the gas pressure is now 20mb.

The issue has always been intermittent from Day 1. Sometimes daily sometimes once a week. There is a G6 gas meter and a 28mm pipe from there to the boiler which splits in s t junction and goes to each boiler right under them, in 15mm.

I’ve still got the problem!! Can anyone else help.

One thing I have noticed is when the boiler switch on the the flame symbol comes up with the boiler output gauge display for a few seconds, switches off and then comes back. I presume this is a failed ignition attempt? It seems to do this regularly.

As I have 2 boilers that fire up at the same time and they’re both under 2 years of age I’ve presumed they both can’t be faulty.

Can someone please help as getting up in the morning to run downstairs to reset these things is annoying beyond words now!

 

[king of pipes]

Gas pipework is possibly undersized to the boilers and you are borderline on what's allowed to be fitted to that meter, if you have any other gas appliances then your in trouble and will need a upgrade you need a GSI to attend and measure the gas rate on full load I suggest you turn off one boiler off reset and try running on one if that operates ok do the same with the next boiler with only one on at a time. Kop

 

[Harvest Fields]

Yes mate. You need a gas safe registered engineer to look at the boilers for you.

 

[Navi Bhander]

Yes mate. You need a gas safe registered engineer to look at the boilers for you.

We have one 4 hob in the house and that’s it.

We had a gd1 or gp1 survey or whatever they do to calculate the load of the meter by Cadent gas and they said we’re on the upper capacity of it but they wouldn’t change it to an U16 as they said it wasn’t required.

One boiler switched off and still have the same issue.

 

[Harvest Fields]

We have one 4 job in the house and that’s it.

We had a gd1 or gp1 survey or whatever they do to calculate the load of the meter by Cadent gas and they said we’re on the upper capacity of it but they wouldn’t change it to an U16 as they said it wasn’t required.

One boiler switched off and still have the same issue.

So it sounds like a boiler issue and as I said you need a gas safe registered engineer to look at it for you.

 

[Aire]

If they're under two years old I'd contact valliant as they'll be under warranty. Just out if curiosity how big is your system, how many rads do you have and how much area is heated by the underfloor?

 

[Navi Bhander]

Gas pipework is possibly undersized to the boilers and you are borderline on what's allowed to be fitted to that meter, if you have any other gas appliances then your in trouble and will need a upgrade you need a GSI to attend and measure the gas rate on full load I suggest you turn off one boiler off reset and try running on one if that operates ok do the same with the next boiler with only one on at a time. Kop

We did initially think this but the problem is the boilers won’t fire up on full load before they switch off.

They ignite on a low flame level and then switch off straight away, reignite with a grumbling noise and then fire up. Ive been told they must do this 3 times before the F28 kicks in.

On max load I’m getting 21 mb into the meter and 19-20 on the exit pipe.

 

[Navi Bhander]

If they're under two years old I'd contact valliant as they'll be under warranty. Just out if curiosity how big is your system, how many rads do you have and how much area is heated by the underfloor?

150sqm downstairs, upstairs is 13 rads and 4 towel rads.

I will give Vaillant a call but then every plumber says it’s practically impossible that both boilers stop at the same time to be faulty.

 

[Navi Bhander]

So it sounds like a boiler issue and as I said you need a gas safe registered engineer to look at it for you.

I’m based in Northwood Middlesex. Is there any recommendations that someone can make?

The boilers have been checked and serviced a few months back by a gas safe engineer who said they were fine. I did mention the issue to him but said nothing obvious there.

He mentioned something about checking the earthing and electrics next.

 

[Aire]

I would say your boilers are oversized and your gas is undersized.

 

[Harvest Fields]

I would say your boilers are oversized and your gas is undersized.

So they need a Gas safe engineer to go back do they not?

 

[Riley]

Also I hope op is not testing the mbar

 

[Last Plumber]

As @Craig Watson says. If they are under two years of age then they are definitely within warranty. I would suggest you get the installer to come back and deal with this or book a visit from Vaillant.
If you choose the latter, there is a charge if the fault is not Vaillant product related.

 

[Harvest Fields]

As @Craig Watson says. If they are under two years of age then they are definitely within warranty. I would suggest you get the installer to come back and deal with this or book a visit from Vaillant.
If you choose the latter, there is a charge if the fault is not Vaillant product related.

This is of course assuming they have been fitted by a registered engineer and have had the warranty set up.

 

[Aire]

So they need a Gas safe engineer to go back do they not?

Definitely and thats the last advice I'm giving op on the subject

 

[chris watkins]

Not withstanding the F28, it would appear you have a you have 2 oversized boilers on a poorly designed system, I take it from the single large pump that there is no low loss header installed? (60kW through 28mm what were they thinking !!!)

Why haven't you gone back to the installer / manufacturer before now?

When you go down to reset, is it both that show the F28 ??

 

[Riley]

I still reckon it’s a pipework isue

 

[chris watkins]

I still reckon it’s a pipework isue

Why if it still does it with just the one switched on ?

 

[Aire]

Why if it still does it with just the one switched on ?

Where does he say this still happens when only one is switched on?

 

[chris watkins]

Where does he say this still happens when only one is switched on?

Bottom of post 4

 

[Riley]

Fair point I hadn’t seen that if that’s the case

 

[Aire]

Bottom of post 4

I see, missed that one 😳

 

[Aire]

Potentially blockage in the pipe?

Could be, if excessive flux was used it could be causing a restriction. Both boilers having the same fault are unlikely to be manufacturer related so either there's an issue with the gas supply or the boilers aren't earthed correctly.

 

[Harvest Fields]

Naughty boy @Riley 😛😛

 

[chris watkins]

What else throws up F28 in the depths of winter !!!
Could be if it is both or either, worth a check wouldn't you say?

 

[Riley]

Well quite. I guess it could be that too

 

[Aire]

What else throws up F28 in the depths of winter !!!
Could be if it is both or either, worth a check wouldn't you say?

Doubtful, he said he's been having intermittent issues for the last 9 months. Although there could be other reasons for that to be causing issues that don't relate to the cold weather.

 

[chris watkins]

Doubtful, he said he's been having intermittent issues for the last 9 months. Although there could be other reasons for that to be causing issues that don't relate to the cold weather.

I know it is not cold all year round but still produces, where does that pipe end up? Just a thought but would need to be on site.

One thing for sure 60kW's through 28mm ain't to clever & on U/F, rad mix, with no separation, another great design.

 

[Navi Bhander]

Also I hope op is not testing the mbar

Nope, plumber or cadent gas has been out approx 20-30 times now.....

 

[Navi Bhander]

Not withstanding the F28, it would appear you have a you have 2 oversized boilers on a poorly designed system, I take it from the single large pump that there is no low loss header installed? (60kW through 28mm what were they thinking !!!)

Why haven't you gone back to the installer / manufacturer before now?

When you go down to reset, is it both that show the F28 ??

The issue was the installer had said it was due to the low main gas pressure. cadent gas tookmonths of coming out and checking before they agreed we had spikes in pressure hence the reason the F28 was coming up.

They rectified the issue by installing a 63mm pipe to the house.

I’m not in the trade and hence had presumed that it was a pressure issue and left it at that.

Now the issue isn’t the gas pressure as they fixed this in December and in all honesty for a month it worked faultlessly.

As the weather has got better the issue has become more apparent again and is daily.

I’ve switched off one boiler and and currently searching for a recommendation for someone to come rectify this for us.

 

[Riley]

Nope, plumber or cadent gas has been out approx 20-30 times now...

Have to ask as you wouldn’t believe the amount of people that think they know what they’re doing

 

[gmartine]

I’m based in Northwood Middlesex. Is there any recommendations that someone can make?

There's a superb engineer and troubleshooter in your area called Andrew Millward of https://www.homecomfortassured.co.uk/ive

Just do what he recommends, as said already sounds like the boilers are well oversized so could possibly be a poorly designed system with no LLH.

 

[Navi Bhander]

There's a superb engineer and troubleshooter in your area called Andrew Millward of https://www.homecomfortassured.co.uk/ive

Just do what he recommends, as said already sounds like the boilers are well oversized so could possibly be a poorly designed system with no LLH.

I will give him a call and keep you updated. Thanks

 

[chris watkins]

I will second the post re Andrew, if anyone can Mr Millward can.

 

[Old Account]

Why do you need two boilers for such a system with 30 kw each running in the same time? As mentioned above to all the others well oversized and get a reliable engineer or perhaps donit via warranty

 

[Navi Bhander]

Why do you need two boilers for such a system with 30 kw each running in the same time? As mentioned above to all the others well oversized and get a reliable engineer or perhaps donit via warranty

I honestly don’t know, I have asked the subcontractors that built the property and they said they are variable output so will work load dependant or something along those lines.

Apparently the heat calculation for the house was 57kw and the space worked out best for 2x 30kw.

I’m not sure tbh but it’s been one nightmare.

I’ve had a various gas safe plumbers out, they all looked at the system and said it’s fine and it’s a gas supply to the property issue. I’m sure apart from cadent I’ve paid 3 local firms to come check it.

The last guy checked it and gave me a certificate to say it’s gas safe tested as well and said it’s a supply issue to the meter.

As you can see I’ve been trying to resolve this and was obviously fobbed off by everyone that it’s a supply issue to the house.

 

[Navi Bhander]

I will second the post re Andrew, if anyone can Mr Millward can.

I’ve spoken with him and he’s coming out tomorrow 🙂

 

[gmartine]

If you use Millward do keep us posted, thanks.

 

[Navi Bhander]

If you use Millward do keep us posted, thanks.

Will keep you updated tomorrow.

Just to clarify with one boiler disconnected the issue is still there on the remaining boiler.

When the controller demands heat, the radiator symbol comes up on the boiler, the pump switches on and after 5-10 secs the flame light comes on with the triangle variable display comes on on the minimum setting. It then switches off within 2 secs and then starts up again after 5-10 then continues to run.

It does this most times I look at it, I presume this is an ignition failure?

I understand the boilers may be missing headers etc and I will have this rectified. But I don’t think this or a bigger meter will fix my issue as even with 1 boiler I have the issue.

I’m really hoping Andrew comes in and works his magic, having spent 15 mins on the phone he clearly knows his stuff.

 

[Navi Bhander]

Just a quick update.

Had Andrew over today. Firstly I agree with the other recommendations, he is such a lovely guy and clearly knows his stuff.

To cut a very long story short he identified the lack of low loss header and isn’t convinced pairing the boilers together is the best way. As I have 2 Honeywell evohome systems to cover all the zones and 2 tanks he needs to double check how to integrate everything together.

However none of this is the cause of the F28.

He checked the pressure at each boiler, 24mb standing that drops to 18 on full load of both boilers when in chimney sweep.

He said that’s on the low side but not enough to give the problem I have.

The f28 is ignition failure and luckily it played up once while he was there. The boiler while having 24mb pressure fails to ignite on its first attempt, something it does on every other start up.

He checked the flue pipe, did various tests on the boilers, co2 checks etc and nothing at all.

He’s going to speak with a few Vaillant contacts of his to check as nothing is untoward but yet both boilers display identical issues even when each one is isolated.

As it stands in the past few days the F28 hasn’t come back with 1 boiler running, albeit it may not start on the 1st attempt.

Andrew has also advised to increase the pipe diameter to the boiler to 22mm instead of using a 15mm pipe from the 28mm pipe.

Any other suggestions to what my f28 fault could be?

 

[gmartine]

We sympathise with your frustration but do give him a chance to get back to you and make the necessary changes as occasionally a combination of events especially where electronics and sensors are concerned can lead to anomolies that aren't easily explained by a fault code. With an untracable intermittent fault it may eventually be a case of replacing parts in a systematic semi-educated way which is expensive but still no guarantee. Do continue to keep us updated as we're also on a learning curve albeit at your inconvenience, and goodluck hopefully you won't need it now Andrew is on the case.

 

[Navi Bhander]

We sympathise with your frustration but do give him a chance to get back to you and make the necessary changes as occasionally a combination of events especially where electronics and sensors are concerned can lead to anomolies that aren't easily explained by a fault code. With an untracable intermittent fault it may eventually be a case of replacing parts in a systematic semi-educated way which is expensive but still no guarantee. Do continue to keep us updated as we're also on a learning curve albeit at your inconvenience, and goodluck hopefully you won't need it now Andrew is on the case.

I fully understand intermittent issues and I respect Andrew’s honesty with all the advice. He’s not given up either, so he’s going to contact his Vailliant chap to do some further fault finding and send someone else over too.

The system installation design will be getting fixed regardless, he’s just doing some research into the evohome system to make sure it will all integrate and function better.

 

[gmartine]

I'm reluctant to tread on anybody toes mid-investigation, let it run it's course but this would be my next areas of concern...

Igniter, gas valve and electronics. You never know both boilers could've been installed with faulty igniters, highly unlikely but a cheapish swap out.

 

[Navi Bhander]

I'm reluctant to tread on anybody toes mid-investigation, let it run it's course but this this would be my next areas of concern...

– There’s a problem with the gas supply to the boiler.

– [/s]There’s air in the pipes.

– The pressure of the gas flow is too low.

– Igniter is defective.

– There is a fault in the gas valve.

– Electronics are defective.

The good thing with Andrew was he’s sonopen to ideas he even asked if the forum had suggested anything else!

How would air enter the gas system?

Once the boiler has ignited it’s fine, it doesn’t switch on which brings up the F28.

 

[gmartine]

See above post again Navi, my strike throughs are like your boilers... unpredictable. It sounds like everything has been done with regards to your gas supply, F28 error includes gas + ignition so that side of things require further investigation imo hence recommending the igniter swap out. It may at this point ask be worth asking Vaillant to participate again IF parts are required.

 

[Gasmk1]

See above post again Navi, my strike throughs are like your boilers... unpredictable. It sounds like everything has been done with regards to your gas supply, F28 error includes gas + ignition so that side of things require further investigation imo hence recommending the igniter swap out. It may at this point ask Vaillant to participate again IF parts are required.

can this fault also so be due to ignition lead

 

[gmartine]

Probably about as unlikely as a faulty igniter, no point assuming anything at this stage.

The simultaneous fault occuring in both boilers is the kicker here which is why everybody has concentrated on the gas side of things to date. Could've been a late Friday afternoon at the Vaillant factory when these boilers rolled out, who knows.

 

[Navi Bhander]

See above post again Navi, my strike throughs are like your boilers... unpredictable. It sounds like everything has been done with regards to your gas supply, F28 error includes gas + ignition so that side of things require further investigation imo hence recommending the igniter swap out. It may at this point ask be worth asking Vaillant to participate again IF parts are required.

Yes, Andrew has the same thoughts. He’s asked to get Vailliant back over again to check them.

The only baffling thing was one boiler will never switch off by itself, always both of them together at the exact same time.

But when you’re clutching at straws and have tried everything then sometimes the most unlikely cause can be the cause.

I’m stuck at work today so will call them in the morning and get an engineer out.

 

[gmartine]

The only baffling thing was one boiler will never switch off by itself, always both of them together at the exact same time.

I don't think your boilers have been paired properly so that may cause some issues. It sounds like whoever designed your semi-commercial system has had a go with trying to design/install it by scaling up their domestic knowledge. I'm sure Andrew will get to the bottom of it...eventually.

 

[Jerry]

I look forward to finding out what the fault is.

 

[Aire]

Did Andrew check the termination of the condensates? Both go to the same pipe so if there is a blockage or partial blockage it may cause an intermittent f28 fault code.

 

[Navi Bhander]

Did Andrew check the termination of the condensates? Both go to the same pipe so if there is a blockage or partial blockage it may cause an intermittent f28 fault code.

This was checked by another gas safe engineer before as well. I remember him pouring water down there and stating there definitely was no issue on that side.

Well the one boiler still hasn’t kicked out yet, but when it ignites it will switch off within 2 secs and then fire back up after 5 seconds.

So the confusing bit is the boiler will actually ignite then extinguish instead immediately, then reignite and work. It does this most times.

Which would mean the flow rate wouldn’t matter, has pressure is fine, the electrics should be fine as it ignites. Andrew even thought it could be a dodgy flue but there are 2 different flues and yet both have the same fault at the same time!

Will be on the phone with Vaillant in the morning and see.

Andrew will pop back as he wants to check the HT lead or something or another as well.

The system layout that he suggests is using the boilers independently, one to do the underfloor and one for the radiators and hot water tank. He wants me to get the accuweather or something on the boilers fitted but it makes the evohome system half redundant so will need to have a think.

 

[chris watkins]

Did Andrew check the termination of the condensates? Both go to the same pipe so if there is a blockage or partial blockage it may cause an intermittent f28 fault code.

Spoke to him today, I think he was going back to check a few things including disconnecting the wastes's.
It makes sense, it could be double trapped or part obstructed.
It has been happening from the start. Would effect both boilers or just the one. Mainly happens around start up just when more condense is produced.
worth a check.
Has anybody pulled the burners to check HeatX and electrodes I wonder ?

 

[Navi Bhander]

Spoke to him today, I think he was going back to check a few things including disconnecting the wastes's.
It makes sense, it could be double trapped or part obstructed.
It has been happening from the start. Would effect both boilers or just the one. Mainly happens around start up just when more condense is produced.
worth a check.
Has anybody pulled the burners to check HeatX and electrodes I wonder ?

It happened a few times June last year and progressively got worse. As we were convinced it was a gas pressure issue and in fairness it did only play up once in a month after the gas pipe was upgraded.

As with all intermittent issues you think it’s cures till it’s not!

Nope the burners have not been touched.

 

[chris watkins]

his was checked by another gas safe engineer before as well. I remember him pouring water down there and stating there definitely was no issue on that side.

Oh well that blows me out of the water. 😕

 

[Navi Bhander]

Oh well that blows me out of the water. 😕

It’s the pipe that comes out of the bottom of each boiler that drips out water?

If that the case I remember the pipes being removed and water being put down the drain pipe that dissappears into the ground and out somewhere to make sure there was no blockage.

 

[Steve weightman]

Seems gas related...maybe dodgy meter governor..just a thought

 

[gmartine]

The system layout that he suggests is using the boilers independently, one to do the underfloor and one for the radiators and hot water tank. He wants me to get the accuweather or something on the boilers fitted but it makes the evohome system half redundant so will need to have a think.

Up to you, I expect his angle is that Evohome doesn't support true weather compensation which'll give the greatest efficiency savings which maybe fairly sizable for a large building. Yes Evohome has plenty of bells and whistles giving you the impression of control but it's really a fairly crude pseudo smart system. Go with the recommendations, if you really dislike the results or lack of controls it can be disconnected and your full Evo reinstated fairly easily I think (Check that with AM).

 

[ShaunCorbs]

tbh i would get the boilers running constant without problems first before you start messing with stats etc

even go down the road of simple controls for now

 

[Navi Bhander]

tbh i would get the boilers running constant without problems first before you start messing with stats etc

even go down the road of simple controls for now

I have been thinking this today.

What I don’t want for do is spend the money on separating the boilers, adding the low loss header, re plumbing everything and then still be left with the fault on the boilers.

I will get the work done asap but want the boilers up and running. What I don’t want is to do this and then find out there’s issues with the boilers, in that respect I’m better off biting the bullet and swapping to one correct spec boiler and save the expense of fitting and redoing the pipework again.

 

[ShaunCorbs]

i would get a llh fitted and the added items to get the system working right then if all else fails this can be still used for a new boiler etc

you sure the new gas main is 63mm seems big

 

[Navi Bhander]

i would get a llh fitted and the added items to get the system working right then if all else fails this can be still used for a new boiler etc

you sure the new gas main is 63mm seems big

63 mm to just under the meter where it reduces to whatever goes into the meter.

 

[Navi Bhander]

Also just a thought here, with my limited knowledge.

If we separated the 2 boilers, one for the underfloor heating so the temperature could be set lower and the other one doing hot water and radiators. As the boilers have CH and HW function on then I wouldn’t really need the LLH? I would just need another boiler wiring centre, and 2 pumps, one for Hw and CH.

 

[ShaunCorbs]

The underfloor heating one wouldn’t like it tbh would cycle like a mother when one or two zones are open

TBH I would keep it as is and sort the pipeing out etc

 

[Navi Bhander]

The underfloor heating one wouldn’t like it tbh would cycle like a mother when one or two zones are open

TBH I would keep it as is and sort the pipeing out etc

At The moment I get 2 boilers firing up for it!

The issue Andrew has by leaving the boilers paired is the hot water cylinder will take longer to heat up as the boilers will only be running at 65’c. Increasing it will make them condense or something or another. I’m an osteopath so a fair bit goes straight over my head!

 

[ShaunCorbs]

I think he means when he separates the boilers as you won’t have 60 kw going to the cylinder only 30kw

Potential with no other load etc

Cylinder will be happy with a flow of 65

 

[Navi Bhander]

Just an update.

With one boiler switched off the other boiler still triggered a F28 code yesterday.

Interestingly I have noted one thing.

It seems to trigger the F28 on the central heating demand for the radiators. As it was a very mild day yesterday the only zone active in the house was our bedroom as it’s set to 20’c as there is a new born in the house.

The evohome system switches the boiler on for 1 min every 10 mins or so to regulate the temp. In reality what happens is the bdr91 relay switches on, the pump switches on but by the time the boiler ignites it only runs for a few seconds before it switches back off as the relay switches off.

Could this scenario some how cause the boiler has supply issue as it’s just ignites and then switches off due to the demand not being required anymore?

I’m mechanically competent and used to restore classic cars. If you start a car but switch it off without it fully turning over it sometimes results in it flooding and difficult to start the next time. In very layman terms could this happen with gas?

 

[ShaunCorbs]

It’s a possibility I would turn that off and make it run for a min of 5 mins before it switches off

 

[Alex Price]

Hi, has anyone tried disconnecting all outside controll interface to the boilers, put the jump cable back in to call for heat and run each one Independently?

I have known a split controll interface spike between the two sides, if the draw on the switch is great enough it can cause some weird resistance values and that can cascade through the pcb, Biasi and morco air pressure switches are good for that. gas supply sounds iffy for the pair but the only constant seems to be the call for heat, Worth a try ?

 

[ShaunCorbs]

Hi, has anyone tried disconnecting all outside controll interface to the boilers, put the jump cable back in to call for heat and run each one Independently?

I have known a split controll interface spike between the two sides, if the draw on the switch is great enough it can cause some weird resistance values and that can cascade through the pcb, Biasi and morco air pressure switches are good for that. gas supply sounds iffy for the pair but the only constant seems to be the call for heat, Worth a try ?

Yep simple controls

 

[Antonio Dinis]

Hi there
See if this helps

 

[Antonio Dinis]

By the way I’m a gas engineer

 

[Antonio Dinis]

Pure or plus are the same on this case

 

[gmartine]

It seems to trigger the F28 on the central heating demand for the radiators. As it was a very mild day yesterday the only zone active in the house was our bedroom as it’s set to 20’c as there is a new born in the house.

As tempting as it is (because you can) trim down demand to the odd radiator. Unless you have a boiler that can modulate 20:1 or so your boiler is not going to like it one bit so open up a few zones/rads even though it seems counter intuitive.

 

[Riley]

By the way I’m a gas engineer

Then please pm your details to @Riley @ShaunCorbs or @Harvest Fields and we can arrange for you to gain your gsr tag and access to gas safe only area. Until you have it then please be wary on commenting on gas issues as our members need to know that we talk gas safety very seriously. Keep posting, introduce yourself hang around. Very nice to have you

 

[Abuali]

Not withstanding the F28, it would appear you have a you have 2 oversized boilers on a poorly designed system, I take it from the single large pump that there is no low loss header installed? (60kW through 28mm what were they thinking !!!)

Why haven't you gone back to the installer / manufacturer before now?

When you go down to reset, is it both that show the F28 ??

I agree with you on the Low Loss header installation but regarding the single large pump and the 28 mm pipes what could they have done if the pipe installation was there and it was not possible to amend the pipe work as for example its all within the house without them being able to rip the flooring up and and install smaller pumps for each area/floor.
What would you have done differently?
Thanks in advance

 

[Riley]

I agree with you on the Low Loss header installation but regarding the single large pump and the 28 mm pipes what could they have done if the pipe installation was there and it was not possible to amend the pipe work as for example its all within the house without them being able to rip the flooring up and and install smaller pumps for each area/floor.
What would you have done differently?
Thanks in advance

There’s pretty much always ways. It just needs careful planning and design

 

[Abuali]

There’s pretty much always ways. It just needs careful planning and design

Would very much appreciate your ideas.
I will be very thankful if you can elaborate more on that.

 

[Riley]

Depends on space, where pipes become accessible, is there a basement, can zones be set up differently. Too many variables to give a one size fits all response

 

[Abuali]

Depends on space, where pipes become accessible, is there a basement, can zones be set up differently. Too many variables to give a one size fits all response

I agree its hard to generalise.
But if you are colled to change a two old boilers installed in series to new boilers and all what you see is that the old boilers installed without low loss header.
The new pipe work installation includes you installing a UF heating in the basement floor and with the client dont want to re-pipe the pipe work installation.
Now you left with a boiler room and only u can see two old boilers with two zones valves that you cannot be sure wt areas they control, the pipe work from the boilers room under the street to the house is 35mm run then to 22mm all over the house. (No plans for the old pipework run, most floors are marble tiles!)
A house with 5 floors(incl lower ground flr where the underfloor heating installed on three circuits) each floor area is around 120 sq m with around 25 radiators allover the house and 210l HW cylinder.
What options would you do apart from installting a low loss header and a single large pump .
Any ideas would be highly appreciated

 

[Riley]

Mate it’s too vague. You go there you plan you discuss with the client the benefits of the install you propose and you work together towards a sensible solution. Are you looking for help with an install??

 

[Abuali]

Mate it’s too vague. You go there you plan you discuss with the client the benefits of the install you propose and you work together towards a sensible solution. Are you looking for help with an install??

Not really help but seen something like that in a job by a quite experienced GSR engineer and and as i am new gas safe ☺️ was trying to see what options could be done as honestly I thoroughly searched for ideas couldn’t find a way other than wt the other gas safe engineer done.
But i always think you guys with all that collective experience from other engineers and brain storming would always find away around almost everything.
Much appreciated

 

[Riley]

Need to see the job mate. Do you have a mentor??? College tutor or something?? Did you do a short course

 

[Abuali]

Need to see the job mate. Do you have a mentor??? College tutor or something?? Did you do a short course

It was a year course, I qualified almost 18 months ago but the job i was talking about was new to me. And unfortunately it was few months ago and didn’t took pictures at that time.
For tutors, i know few engineers as i am currently also work with one ( not best wage but am very satisfied am building up my experience) and personally and without offense i do hardly take wg college tutors would say as alot are either “lecture” on theory and books based rules or without all the very fast moving sector.
Experience and examples i see here on this website would need many long years in colleges.

 

[Riley]

That’s kind of the point though mate you do a full apprenticeship so you learn how to size systems and design systems and understand the different ways to make one work. College tutors may not be pushing the most up to date technology but what they will push is solid ground work so that you can sit down with a pencil and paper and correctly size and specify a system. If you have the spec of a larger property then some companies will design it for you. The lectures and books as you call it are the groundwork’s knowledge wise to how to do our job properly. Do you ever make reference to your gas regs when out on the job. You should no one knows it all. It’s the same principle. If you are in anyway not confident with this larger job then turn it down as it will come back and bite you this I guarantee. Also your comment about working round things. Sometimes the customer just needs to be told the correct way to do it and they have to accept it or you need to walk

 

[Abuali]

That’s kind of the point though mate you do a full apprenticeship so you learn how to size systems and design systems and understand the different ways to make one work. College tutors may not be pushing the most up to date technology but what they will push is solid ground work so that you can sit down with a pencil and paper and correctly size and specify a system. If you have the spec of a larger property then some companies will design it for you. The lectures and books as you call it are the groundwork’s knowledge wise to how to do our job properly. Do you ever make reference to your gas regs when out on the job. You should no one knows it all. It’s the same principle. If you are in anyway not confident with this larger job then turn it down as it will come back and bite you this I guarantee. Also your comment about working round things. Sometimes the customer just needs to be told the correct way to do it and they have to accept it or you need to walk

I do totally agree Riley.
I never meant to underestimate the importance of tutors and honestly it did benefit me alot and i still do almost on daily basis after work try read a book or online articles. And strongly believe in the importance of the therotical and scientific aspects of heating systems, just as any other domin.
Regarding this large house as I mentioned before (my mistake if I didn’t clarified it) I didn’t do any work on it, its just i came across it with the engineer i work with and just was trying to “explore” what options could been done more than what he could have done and recommended.

The dilemma I personally find is most of the jobs esp bigger houses most of the times i see engineers have to take over from what had been done, work on old pipe installations so not as easy as new system where you can completely design it from the scratch depending on the therotical and “pen and paper” way. The knowledge and to great extend the experience will definitely decisively help.
Thanks for all your replies and time Riley, very much appreciated.

 

[Chalked]

Edited

 

[gmartine]

@Abuali

Theoretical questions regarding low loss headers (or close-coupled tees)

 

[chris watkins]

College tutors may not be pushing the most up to date technology

Some do, or at least we try.

The dilemma I personally find is most of the jobs esp bigger houses most of the times i see engineers have to take over from what had been done, work on old pipe installations so not as easy as new system where you can completely design it from the scratch depending on the therotical and “pen and paper” way.

It is not so much a dilemma Abuali, it is simple a challenge after all you can only do what you can do with what is in front of you. The knack I guess is to do your best & then set out the limitations as you see them but backing it up with just as much “pen and paper” work as you might on a new project.
For instants take the system & photos posted on this thread.
With only a small amount of research it would be clear that these Vaillant boilers can't work correctly without a minimum flow rate at all times so some form of hydraulic separation should have been created when they were installed. If the existing system only had one 28mm F&R then you would have to set out the limitations of this you could do a flow calculation or in my case check the pipe carrying capacities set out in my "Domestic Heating Design Guide" which shows that a 28mm copper pipe can only provide 40kW at 20deg C drop (at 7C it is only 14 which is what the U/F runs at) so it begs the question why a total boiler load of 60 has been provided?

150sqm downstairs, upstairs is 13 rads and 4 towel rads

Now I am not on site, if I were I could go measure all of the above & work out the heating load (or even do full heat calc's) but as I not I could apply some experience - such as rads tend to average out at around 1.5kW in older houses so around 25.5 for the rads + U/F tend to require around 100 W/M2 so around 15kW's giving a total max heating load of 40.5kW (at -1 or -3 out side temp) so why install 60kW boiler power ??
Do you see how you should be approaching the problems ?

 

[Riley]

Brilliant explanation Chris. No offence meant by the college tutors thing. Mine were brilliant and were very much up to speed, sorry the op seemed to imply his weren’t quite so

 

[chris watkins]

Brilliant explanation Chris. No offence meant by the college tutors thing. Mine were brilliant and were very much up to speed, sorry the op seemed to imply his weren’t quite so

Absolutely no offence taken Riley!! 😎
I know all about the poor levels of knowledge & experience out there in FE land. When you have seen store man or newly qualified Plumbers stuck in front of a class & asked to deliver this very technical subject it is no wonder there are so many poor people out there.
It was just to point out (& as you found) there are still a few of us who try very hard to stay on the cutting edge, mind you what is all this malarkey about controlling a boiler via your hand held telephone....? 😛

 

[Riley]

Well it’s just a gimmick. The whole boiker plus thing is too

 

[pepsidog]

Just done quick pipesize calc and for 8 metres gas pipe, 8 bends and 1 tee on 60kw nett boilers smallest gas pipesize is 35mm. On your picture you show 28mm but then 15mm + couple of bends to boiler . Pressure drop through this would be huge. For these size boilers should be 35mm to as close to gas inlet as possible then 35mm to 22mm reducer then 22mm to 1/2 conex to boiler.
You need gas safe engineer to work out properly. You mention original gas pressure were 16mb. Not sure whether this is at meter or appliance but too low and no gas safe engineer would commission at these pressures as appliance would be classed as “at risk”.
Looking at picture it looks like a diy install, cables all over place.
Best to get Vaillant out to do properly.

 

[Aire]

16mb is not too low and i would commission a boiler at this pressure. All boilers sold in the UK have to work properly at pressures down to 14mb. The only thing you have to maintain is the 1mb drop accross the installation pipe work. And yes his gas pipes are probably undersized but we dont know where his metre is in relation to the boilers so we can't know for sure. he's also getting the same issue when only one boiler is working, in which case the 28mm supply would be adequate.

 

[Abuali]

The only thing you have to maintain is the 1mb drop accross the installation pipe work..

How would you achieve or confirm that 1 mbar drop?

Would you add a test point at the end of pipework just before the boiler isolation valve?

Sorry as i had not seen any engineer install a test point in there, apart from commercial (for tightness testing mainly)

As most of posts in many forums will say the P1 at the gas valve is the test point although gas safe Register Technical Bulletins (tec bulletin 129 published 16 February 2016) acknowledges a possible drop of 0.5-2.5 mbar at the inlet side of the appliance gas control valve.

The Gas supplier must provide a minimum of 19 mbar at the outlet of EcV at peak flow conditions. The pressure drop across primary meter can be up to 4 mbar, leave us with 15 mbar take drop of 1 mbar for pipework then its 14 mbar, and average of 1.5 mbar drop through the appliance pipework and then you end up with a reading of 12.5 mbar at Inlet to boiler gas valve.

I think, and please do correct me if am wrong on this: the key issue in this whether the pressure drop affects the safe operation of the appliance or contibutes to a fault condition then GIUSP should be followed and a Gas rate will confirm a satisfactory operation (GSIUR 26.9(c)) Esp with the zero govenor or Air/gas ratio valves where burner pressure measurement is not appropriate

 

[Riley]

The maths will tell you if your pipework to appliance is below 1mbar drop. What the appliance will work at is inconsequential as this prerequisite must be met in the first instance.

 

[Harvest Fields]

Why are we still talking about this in an open forum? I thought the OP had an engineer that was sorting him out?

 

[Riley]

Yes it has strayed rather

 

[gmartine]

Could this scenario some how cause the boiler has supply issue as it’s just ignites and then switches off due to the demand not being required anymore?

I’m mechanically competent and used to restore classic cars. If you start a car but switch it off without it fully turning over it sometimes results in it flooding and difficult to start the next time. In very layman terms could this happen with gas?

How are you getting on, anything to update?