Has my builder ruined my boiler?

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Has my builder ruined my boiler?

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windle poones

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My boiler is a Potterton Puma 80. Its old but very well maintained and was working perfectly before my builder modified my central heating system.

I contracted a builder to build a small extension to my home. During the extension work the builder’s plumbing guy fitted two motorised valves. His logic was to enable independent control of the central heating temperatures in the main house independently from the extension.

The work was done in the winter and seemed to work fine apart from a few occasions when the pilot light went out for no obvious reason known to me, however pushing the piezo igniter re-lit the pilot flame and then the boiler would continue as normal. Keeping in mind, because of the cold weather either zoned heating circuit or both would be on and DHW.

Now Easter is here and with it the warm weather there is no demand for heat from either heated zone. So the motorised valves are both turned off. I noticed a boiling sound, (Kettling sound) coming from my boiler. Then the boiler shut down with the pilot light extinguished and the pump now running all the time.

On checking the boiler the pressure in the system was very nearly down to zero. I tried to re-pressure the system via the filler loop, but this was not possible, because of the motorised valves being both off had effectively isolated all the radiators in the house and extension from the boiler.

I found by turning the motorised valves on, effectively demanding hot water. I could now re-pressurise the boiler to 1.25 bar via the filler loop. Everything then worked as normally. However when I turned off both the motorised valves, the boiler kettled and shut down again with a loss of system pressure.

Any suggestions/advice would be very much appreciated.
 
Riley said:
So I maintain there is literally no reason why it shouldn’t go up as well as down to the two motorised valves
Click to expand...

The filling loop is on the flow. On that boiler the diverter valve opens when the diverter valve gets up to a certain temperature causing it to open.

I will remain with what I said before get them back as if its firing when both valves are shut it will be a simple wiring fault. Also ask them to put a bypass on it as I said in my last post.
 
Thanks Riley, the only problem I now have is, the extension build is new and I have not signed off on the builder's snagging list. So a small final payment is due. I don't know whether I should trust him to put it right or to call in a known good plumber to rectify his work. o_O
 
Were it me I would insist on a proper plumber and tell him you’ll be knocking the difference off his bill. He may, fairly, insist on being given the chance to put it right. What has been done is 90% right in terms of building regs but it’s Your call really.
Two questions:
Who rebuilt such an old boiler?
Do you have a thermostat in each zone?
 
No I think it’s as Bogrodder said there’s a non return on the diverter
 
Last edited:
In answer to your two questions:
1. It was rebuilt by a tech specialist from the company that now owns Potterton. I had an expensive maintenance contract with British gas. During one of their service visits their engineer bodged and damaged the boiler. I refused to accept a new Worcester Boch as a replacement. The rebuild was paid for by British gas after a long running dispute where they finally admitted liability.

2. Each zone is controlled by separately wired "Floureon heating thermostats". They are highly accurate I have tested them with an infra red sensing meter.
 
Hi Millsy,

My reasoning was. The existing boiler was the most reliable I have ever owned. It had given me 25 years’ service at the point when it was bodged. It had always been maintained to a good standard. I have always been fan of the old saying “If it aint broke don’t fix or replace it”.

In another home I had a boiler new in 1964, by Valliant. It was still working fine when I sold the home in 2003. Both boilers were always properly maintained.

I had considered the Worcester Boch, but had heard they were only slightly more efficient and could be troublesome unless I was replacing the entire system, pipes and rads. My own research led me to believe I would be lucky to get seven years from one - WB.
 
I’d imagine efficiency wise you are far worse off but I do agree with your adage re if it ain’t broke. Plus I’d imagine parts will be scarce for the puma in the next few years. Did you not also say you’d had new pipework etc?
 
No not new pipe work. I had the whole system cleaned by a guy specialising in power flushing, that's all he did. He forward and reverse power flushed to remove the debris that had collected in the radiators and the pipe work. All rads where individually disconnected and power flushed. This was after the whole system had been flushed through. The process took five hours from start to finish.
 
In retrospect I probably should have gone for a new boiler, maybe a Valliant. I had checked spares availability for the Puma range before making my decision and was told the heat exchanger for the Puma 100 had been discontinued, but all parts were still available for the 80. However that was 2 years ago.
 
It’s amazing how quick things change but if your boiler is in good working order then I keep everything crossed for you that you don’t require any further repairs any time soon. Anyway keep us updated as to how you resolve the bypass issue
 
I am surprised "well maintained" and "British Gas" cropped up in the same sentence,TBH.

And, to be pedantic, the filling loop NRV should be on the Cold mains side.
 
Not doubting you but why??? It always made sense to me when there are two taps but in the instance where it’s tap hose nrv it makes sense because you’d never be able to remove the hose correctly
 
Riley said:
Not doubting you but why??? It always made sense to me when there are two taps but in the instance where it’s tap hose nrv it makes sense because you’d never be able to remove the hose correctly
Click to expand...

It was my understanding that you required two taps by regs anyway?

You can see why you have the NRV on the cold, as it's less of a dead leg.
 
But there’s no dead leg because the hose should be removed, alright maybe mm in it but seriously.
 
No but I’m arguing regs if you say there should be two taps then the hose should also be removed. Sorry I’m not being pedantic I’m genuinely querying. I cannot see what difference it makes what the reasoning is for the nrv on cold
 
Riley said:
No but I’m arguing regs if you say there should be two taps then the hose should also be removed. Sorry I’m not being pedantic I’m genuinely querying. I cannot see what difference it makes what the reasoning is for the nrv on cold
Click to expand...
I wasn't disputing the fact that the hose shouldn't be removed, I was just simply stating that hardly anyone actually removes the link.

I thought there was some reg about the NRV on the filling loop, but I can't find it to hand. Years ago, it was as you say NRV on the heating side. Then about 10 years ago I thought they changed it and required the NRV to be on the cold main. Incase someone left the filling loop open on the cold side and the dead leg within the loop.

Even if it isn't a reg about it, isn't it better practice for it to be on the Cold? You remove the dead leg (If one is created by the customer), plus you can drain the boiler easily when recharging the expansion vessel or maintenance :p.

Two taps - at least if one is passing you have a fail safe on your second tap.
 
Oh I totally agree with two taps don’t get me wrong but to me it’s logical to stop the heat at the return end so there is no inadvertent heating of the cold side. I cannot see where a dead leg occurs if there is no hose though.
 
Riley said:
Oh I totally agree with two taps don’t get me wrong but to me it’s logical to stop the heat at the return end so there is no inadvertent heating of the cold side. I cannot see where a dead leg occurs if there is no hose though.
Click to expand...
You're right, there isn't one when the hose has been removed. But my point kind of was, no one ever removes the hose.
 
windle poones said:
Thanks Riley, the only problem I now have is, the extension build is new and I have not signed off on the builder's snagging list. So a small final payment is due. I don't know whether I should trust him to put it right or to call in a known good plumber to rectify his work. o_O
Click to expand...

Legally the original contractor is entitled to be given reasonable opportunity to put the situation right. You’re well within your rights to insist the work is undertaken by a competent person. Sounds very like you have the experience to decide for yourself if the guy is flanneling you.
 
OffshoreGas said:
Legally the original contractor is entitled to be given reasonable opportunity to put the situation right. You’re well within your rights to insist the work is undertaken by a competent person. Sounds very like you have the experience to decide for yourself if the guy is flanneling you.
Click to expand...
As you say however you are well within your rights also to refuse access if you feel they have acted outside scope or unlawfully
 
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