Hi, new member and in need of help with y plan system.

[ckgreenall]

Hello one and all, I have often looked at this place for hints and tips but am really struggling now. We recently had a new boiler and radiators fitted to our y-plan open vent system. The new boiler is an Ideal logic plus heat 30. Our system has a sunvic time clock, Honeywell stats and a 3 port mid position valve.

In a nut shell, the boiler is reporting a no flow error which is driving us mad. The boiler initially fires up, runs for a couple of minutes and then shuts down with the error. It does the same on both CH an HW setting. We have had both the CH and HW red hot on the odd occasion but once the system comes to rest, the next time we get the issue.

At the moment we cant get any HW and minimal CH. the one thing I will say is that the return pipe only ever gets warm at best which would suggest we do have a flow issue, but we can't work out why.

During the course of investigation we have put in a new pump, auto air vents, air separator and even had the pump wired direct to a plug to keep it running but still get the no flow error.

My plumber is totally out of ideas, any suggestions?

Many thanks,

Chris

 

[AWheating]

has the wiring been checked against the boiler manufactures instructions? has the flow and return pipework been checked for blockages? are the isolators full open/not blocked at the boiler? are the flow and returns crossed?

 

[stratplus]

Has the pump been fitted upside down? I had this problem once with boiler cutting out (open vent thermal store) and pump was upside down.

 

[stratplus]

Also check the pump valves are open.

 

[chris watkins]

That is a very big boiler how big is your house & when the boiler was installed was a filter / magnetic clean installed before the boiler ?

 

[ckgreenall]

All, thanks for your replies. In answer, the flow and return are the right way round. When the boiler fires we get very hot on the flow right up to the airing cupboard, through the pump and the 3 position valve, into the cylinder and through the flow to the rads. At very best we only get luke warm on the return from the rads and the return out the bottom of the cylinder. The pump whilst upside down is installed that way as it is on a downward flow pipe (if that makes sense?).

Re size of house, we are a 4 bed detached with double integral garage. 14 rads including towel rails and a hot water cylinder. Pipe run from boiler which is in the garage to the airing cupboard which is upstairs in mid of house is around 10 meters.

Re the wiring, pump is wired direct to boiler as Ideal state it should be.

All valves checked and double checked, in fact if we are getting a call for heat on the boiler if I half close one of the valves just above the boiler you can hear the water rushing past, so I know we are getting flow of some sort.

Finally, we do have a TF1 filter just above the boiler on the return and this has been removed and put back in to ensure it wasn't the cause of the poor flow.

Thanks again for all your replies.

Chris

 

[ckgreenall]

Just something else to add having just been upstairs monitoring the pump etc in the airing cupboard, when the pump stops we get a gurgling type sound along with water being spat out of the vent into the header tank. Should it be doing this or could this be linked to the problem?

Cheers,

Chris

 

[chris watkins]

No, water should not be coming out of the open vent, as this adds oxygen to the water & increases corrosion, it is most likely due to the pump / pipework not being positioned correctly, although the modern boilers have such small water ways & therefore very high resistant's that this lead to this as well, especially when the system stops & starts. It sounds as though it is a circulation problem with such a big boiler it will need a high water flow rate to carry the heat way otherwise boiler reads the rise in temp & shuts down (21.5L/M). As long as you are sure that no muck has got into the new boiler I would be looking at the pipework around the pump / C/F & open vent position. What size pump & pipe work have you got between the boiler & pump position?

 

[ckgreenall]

Hi Chris, thanks for the reply. We have 22mm pipe from the boiler to the pump and then onwards into the system/s. It is also 22mm on the returns. We then have 15mm to all the rads.

I am beginning to wonder if there is a blockage on the return between where the CH/HW returns join together and the boiler as we seem to have a common flow problem. I think the next course of action is to replace that run of pipe and see if it gets any better.

Chris

 

[TBServices]

I've had this error on the last heat only logic I did, caused by an airlock in the old pipework. Had to put some well positioned air vents in the system to shift it.

Have you considered converting to a sealed system?


Sent from my iPad using Tapatalk HD

 

[chris watkins]

Hi Chris
Instruction suggest 28mm pipe work for the 30 & on a system of that size I would thing your need at least a 15/60 (6Metre head) pump to over come the friction & shift the required water. This is why with these big boys (boilers) it is better to install a low loss header.
CW

 

[ckgreenall]

I've had this error on the last heat only logic I did, caused by an airlock in the old pipework. Had to put some well positioned air vents in the system to shift it.

Have you considered converting to a sealed system?


Sent from my iPad using Tapatalk HD

Hi that has been suggested and I guess is a consideration if we continue to have issues.

 

[ckgreenall]

Hi Chris
Instruction suggest 28mm pipe work for the 30 & on a system of that size I would thing your need at least a 15/60 (6Metre head) pump to over come the friction & shift the required water. This is why with these big boys (boilers) it is better to install a low loss header.
CW

Hi Chris,

We have installed a new Grudfoss Super selectric 15/60 pump as part of our investigations.

What do you mean by a low loss header?

Cheers,

Chris

 

[chris watkins]

Hi Chris
have a look at this post &/or search V.A Heating Ltd they have details.
http://www.ukplumbersforums.co.uk/central-heating-forum/36366-low-loss-header.html

 

[RGII79]

Is your pump on the flow or return pipe is the boiler a heat only or system 30

 

[DirksPlumbing]

Just something else to add having just been upstairs monitoring the pump etc in the airing cupboard, when the pump stops we get a gurgling type sound along with water being spat out of the vent into the header tank. Should it be doing this or could this be linked to the problem?

Sounds incredibly like a high amount of air getting compressed by the pump and releases on stop. Forgot to bleed some radiators? Other than that it sounds first class like an air lock entrapped in a non suitable laid out pipe section.Why did I not read about an ABV by now? Any bypass at all fitted?

 

[RGII79]

Sounds like a problem with the position of pump if your pitching into the expansion tank .might be better to seal the system.

 

[ckgreenall]

Is your pump on the flow or return pipe is the boiler a heat only or system 30

Hi, The pump is on the flow. Pipe leaves the boiler, up to the airing cupboard, into an air seperator (just fitted to see if this would resolve issue), into the pump and then the 3 position valve.

The boiler is a heat only.

Cheers,

Chris

 

[ckgreenall]

Sounds like a problem with the position of pump if your pitching into the expansion tank .might be better to seal the system.

Hi, the pump is after an air seperator and before a 3 position valve.

 

[ckgreenall]

Sounds incredibly like a high amount of air getting compressed by the pump and releases on stop. Forgot to bleed some radiators? Other than that it sounds first class like an air lock entrapped in a non suitable laid out pipe section.Why did I not read about an ABV by now? Any bypass at all fitted?

Hi Dirk, when you say bypass what do you mean?

Thanks,

Chris

 

[DirksPlumbing]

This is why with these big boys (boilers) it is better to install a low loss header.
CW

Seen the LLH installation, looks marvelous. But I am not a big friend of them as they decrease the system efficiency by artificially lifting the return temperature and therefore decreasing the condensation effect.

Better is controlled zoning. Honewell does some nice valves to ensure that the zones are getting what they are due. You can then ABV each zone individually to use the pipework as buffer for the boiler output.
(Add: saves adding pumps using electric power)

The 15/60 would struggle on heavy use of microbore already with less than 20kW.

 

[ckgreenall]

Hi Chris
have a look at this post &/or search V.A Heating Ltd they have details.
http://www.ukplumbersforums.co.uk/central-heating-forum/36366-low-loss-header.html

Thanks Chris, that's a good plain English explanation on the low loss header.

We are going for a swap out of the return pipe work tomorrow to see if that is the issue. One other symptom that points towards poor flow is that when ever I go to bleed the tf1, I always get at least 5 secs of air... Which suggests to me that we are not getting enough water return to the boiler.

Cheers,

Chris

 

[RGII79]

Sound like your pumping up vent pipe and loosing flow through return what type of boiler had you got before or is this new install
i always fit pump on the return on a open vent system easier to balance and less problems pitching

 

[RGII79]

Your circulating through one pipe your vent and feed is becoming a circuit

 

[DirksPlumbing]

Hi Dirk, when you say bypass what do you mean?

A bypass is a link from between the pump and the control valve towards the return to have circulation even if the midposition valve is on CH demand only and all TRVs are (mostly) shut.

Nowadays an Automatic Bypass Valve should be fitted. That contravenes the use of class A pumps as the manufacturers state not to use ABVs with them.
But it still works in constant pressure profiles.

 

[DirksPlumbing]

I think if the installer did not know about a bypass he most likely did not know about air pockets and water sacks either rather than proximity fill/expansion.

 

[ckgreenall]

All,

Thanks again for all your replies, its good to get some other opinions as this fuels the thought process. Re the original boiler, it was a Myson Apollo 50/65 which had been in since the house was built around 22 years ago. The only issue we had previously was getting the downstairs rads to come on after the summer and the rads only getting hot at the top which we were told was down to sludge in the bottom. This was the driver to replace the rads and while we were at it put a nice new efficient boiler in...... which to this point hasn't worked properly since installation 4 weeks ago.

Actually, that probably isn't a fair statement... its the system at fault here. The boiler creates heat and it gets to the airing cupboard.. just not much further beyond.

We are swapping out the return pipe later today from the point where the CH & HW returns join back to the TF1 which is just above the boiler and we will go from there. I'll report back later.

Cheers,

Chris

 

[peteheat]

Pipe size appears to be one issue.

 

[ckgreenall]

Hi All, quick update. Replaced the last 5 meters of return pipe and no joy. Also put a secondary pump in place of the tf1 (so pumping direct into the boiler on the return) and exactly the same result. The boiler still reporting no flow, stopping the pump in the airing cupboard and spitting water into the header tank.

I have had a suggestion of power flushing the system. Would this be a good step?

Thanks,

Chris

 

[chris watkins]

Was it not cleaned before the new boiler what in, then ?
It might be a partly blocked heat exchanger ? When boiler does fire how quickly does the flow get hot & to what sort of temp ?

 

[ckgreenall]

Was it not cleaned before the new boiler what in, then ?
It might be a partly blocked heat exchanger ? When boiler does fire how quickly does the flow get hot & to what sort of temp ?

Hi Chris,

The system was cleaned prior to the new boiler being out in but to what standard I don't know. I had thought about a blockage within the boiler so maybe a system flush would cure that. When the boiler fires it gets hot on the flow very quickly right up to the airing cupboard such that you can't keep your hand on the pipes. For the CH the boiler will fire for a good 3-4 mins before it switches off and reports the flow error, however for the HW it will only go for around 2 mins. In both instances we get hardly any heat on the returns anywhere within 8-10 meters.

Cheers,

Chris

 

[RGII79]

blank off f&e pipes and try pressurising system to 1.5 bar and vent all over if ther is no blockage and your flow and returns arent mixed up its a blockage somewhere

 

[ckgreenall]

Hi All,

Ok quick update on this. Yesterday I cleaned out the header tank (which hadn't been done!) and the put 2ltrs of Sentinel x800 into the system and whacked the pump up to 3. Nothing changed over night but came home this evening to the system up and running. Return pipe nice and hot and boiler running away nicely. Just cleaned out the TF1 again and will monitor for next few days.

I am hoping that this has been down to dirt remaining in the system from the install.... Fingers crossed.

Thanks all so far for your input and suggestions.

Regards,

Chris