Worcester Boiler issue.

[Ultimate]

Hi, I'm trying to solve a problem with a boiler for a customer, which I can't even establish the model number of.
There is no model number stamped on the boiler, and the customer has lost all documentation, so here is what I do know about the boiler. It is a condensing combi boiler which I estimate to be around 3 years old. It has the mechanical type timer, but from all pictures I can find, lots of models look identical...
I'm hoping that this may be enough info for the problem to be identified as I'm guessing most of this range will have the same arrangement of inlets/outlets.

The customer has already called out the installers of the boiler, who have said the boiler is fine but there are two mains water feeds going to the unit causing an imbalance of pressures.
The taps in the bathroom/kitchen are fine, but when a higher demand of heated water is needed (shower/bath) the higher temperature cannot be achieved/maintained and the boiler can be heard turning itself on and off which would explain the water fluctuating between hot and cold.

Any help would be appreciated, especially if someone has a pipe work connection diagram!

Thanks in advance

 

[Puddle]

Well maybe you should be looking at the shower,could be the cartridge faulty, not the boiler, if their technicians have had a look, and could not find anything wrong with it, it will maybe take someone with a bit more experience than yourself to pick fault up,if indeed on boiler

IMHO

 

[Ultimate]

I'm curious as to why you assume I'm not experienced? No, I don't know every model of boiler out there, but then I don't need to, I'm sorting the plumbing connected to one. The boiler has a clean bill of health, so no need to dig deeper there right now.

You may also note that the cartridge can be ruled out as the bath is equally as bad...

I joined this forum as I thought it would be friendly and helpful, was I wrong?

 

[Puddle]

No you are not wrong,I hope,we try to be friendly and helpful but also honest, am sorry if I made you think otherwise,
The cartridge has not been ruled out also maybe the problem is at the shower as regard the cold mains over powering the hot supply, it may require regulating down slightly, also maybe the non return valve on shower hot stuck open or maybe does not have one and cold is also going down to bath hot, being a close outlet ,as well
If you do not have, maybe put an isolation valve on shower cold, close it and run bath tap see if operation improves but also could have a flow rate problem with bath tap also, also if valve closed slightly shower may work correctly,if so add regulator
Would think the boiler engineers would be talking about shower not boiler when mentioning two different water pressure feeds
imho

 

[GreenArmy]

I would assume you are not experienced, because everyone knows to look at the boiler data badge for model number of boiler.

 

[newbie1]

have to agree seems to be a lot of questions asked that hint at inexperience
all boilers will have some kind of data badge or gc no

 

[Ultimate]

I'm totally overwhelmed by the help - thanks.
If no-one has anything useful to add, then please say nothing. There's plenty of other things other than the boiler (which has been checked) to be able to help with.

Isn't the point of a help forum to erm, try and help if you think someone is inexperienced, rather than point and sneer?

I'm twenty miles from the customer, I'm trying to obtain info before I go back, reading plates etc from this distance isn't easy!

 

[newbie1]

sorry before moving on to trying to work on the boiler are you infact gas safe registered...you have been to the boiler but dont understand the pipework??cant find a data badge??and cant tell what boiler it is
sorry but it would seem you shouldnt infact be touching the boiler as the checks needed will require gas safe registration as there can be numerous reasons for this problem
no one is against advising on plumbing issues but i for one and i am sure many others may agree dont like telling non registered people how to work on boilers
as its a combi the only place that can cause a temp problem with water is the boiler

 

[Ultimate]

I'm not after info for touching the boiler. I've explained, no need to! I'm not Corgi, have no intention of removing the casing or touching any gas fitting what-so-ever. Can we please move on from that part of things as I'm not asking for info about it.

As a plumber, I'm allowed to plumb the water side of things, chances are that I won't need to alter much, but I do need to verify connections. The boiler company have diagnosed the fault in my OP. They have now said to call in a plumber as there seem to be two feeds in for the water (which I've already explained). This is the only area I'm looking for help in.

I'd better re-iterate again, I'm not going to touch the boiler, I'm not going to work on the boiler, I've looked at the casing to find a model number, there isn't one without removing the casing - I haven't done this as I'm not supposed to, and yet I'm getting slated for it???

 

[newbie1]

ok well heres is my opinion only
people who fitted it maybe suspect,has benchmark been filled out with gas engineers no etc
as this hints at a flow problem if sink and basin taps get hot water then the bath taps are the clue as extra volume of water flow is causing boiler to lockout so i am incline to think problem is still at boiler end

 

[Ultimate]

No you are not wrong,I hope,we try to be friendly and helpful but also honest, am sorry if I made you think otherwise,
The cartridge has not been ruled out also maybe the problem is at the shower as regard the cold mains over powering the hot supply, it may require regulating down slightly, also maybe the non return valve on shower hot stuck open or maybe does not have one and cold is also going down to bath hot, being a close outlet ,as well
If you do not have, maybe put an isolation valve on shower cold, close it and run bath tap see if operation improves but also could have a flow rate problem with bath tap also, also if valve closed slightly shower may work correctly,if so add regulator
Would think the boiler engineers would be talking about shower not boiler when mentioning two different water pressure feeds
imho

I've tried reducing the pressure for the cold to the bath/shower as fortunately, there is a tap for both the hot and cold feeds but this failed to help.
The reason I'm inclined to agree about the two feeds is that when I turned the stopvalve off, the boiler seemed to still be getting water fed to it, but all other taps etc were off as expected.
The stopvalve comes in very near to the boiler and can easily be seen to be connected to the boiler. The second feed is the mystery.

 

[newbie1]

the boiler has a cold feed and then a sep filling loop is my guess

 

[oldplumber]

cant fathom why any boiler would have 2 mains feeds into it, are you sure youve checked all the pipes and identified them ok, ie central heating flow/return, cw in , hw out, gas, prv outflow, condensate drain. Not being sarci but 2 mains feeds doesnt ring true.

More likelely that the property has 2 cw feeds, one directly to the attic for cw tanks that may now be supplying the cold taps etc and one cw main direct to the kitchen for the cold tap and on from there. Hence why you may have turned off one stopcock to find another is supplying water elsewhere in the property. Trial and error needed here ie kill the water company valve in the road and check all is turned off. In older victorian houses this set up is quite common, with an old lead pipe supplying the roof feeds still and a nice new plastic pipe running to the kitchen. this leaves with an old slow feed to the tanks in the attic and any feeds off there and a nice supply to the kitchen. Took me a while to cotton onto this in my own house when i was trying to isolate the tanks in the roof and i had killed the supply to the kitchen yet i still got wet when i broke into the "dead" supply in the roof!

 

[Tafftaz]

Had a temp problem like this with a new worcester 28i junior. Called worcester as it was under warranty and engineer came out and diagnosed a faulty heat exchanger.

 

[Ultimate]

the boiler has a cold feed and then a sep filling loop is my guess

A seperate filling loop that isn't turned off with the mains water?

cant fathom why any boiler would have 2 mains feeds into it, are you sure youve checked all the pipes and identified them ok, ie central heating flow/return, cw in , hw out, gas, prv outflow, condensate drain. Not being sarci but 2 mains feeds doesnt ring true.

More likelely that the property has 2 cw feeds, one directly to the attic for cw tanks that may now be supplying the cold taps etc and one cw main direct to the kitchen for the cold tap and on from there. Hence why you may have turned off one stopcock to find another is supplying water elsewhere in the property. Trial and error needed here ie kill the water company valve in the road and check all is turned off. In older victorian houses this set up is quite common, with an old lead pipe supplying the roof feeds still and a nice new plastic pipe running to the kitchen. this leaves with an old slow feed to the tanks in the attic and any feeds off there and a nice supply to the kitchen. Took me a while to cotton onto this in my own house when i was trying to isolate the tanks in the roof and i had killed the supply to the kitchen yet i still got wet when i broke into the "dead" supply in the roof!

It's a one bed flat, no water tank storage at all...

I'm aware of the old system set-up. I can't see any earthly reason why there are two that end up in same location.
I've diagnosed there are two feeds. Another company has also diagnosed this too. Of course I can work out the majority of pipe feeds, but without knowing 100% which is supposed to be which, it's difficult to determine where the wrong feed is.
I guess I'll have to try capping off the 2nd feed to see if this helps. I think there was an issue with the street stopvalve which hindered progress.