Has my builder ruined my boiler?

[windle poones]

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.

 

[OffshoreGas]

Didn’t say to fit a zone valve did I. OP alluded to the rebuild of the boiler which I was questionning

Sorry, I didn’t read it as the boiler had been rebuilt some time before the builder had worked on the system.

 

[OffshoreGas]

As you say however you are well within your rights also to refuse access if you feel they have acted outside scope or unlawfully

It’s generally not looked on favourably by the small claims court if you’ve refused to give a contractor fair chance to put right what may be an honest mistake.

Neither the pipework nor electrical work is notifiable under building regulations so not sure how you’d prove the guy wasn’t competent.

 

[Riley]

Again I was referring to whether or not the builder had acted unlawfully in terms of working on the boiler. They don’t get a second chance there

 

[OffshoreGas]

A 30s google search turned up the manual for your boiler, in section 1.6 it clearly stares the diverter valve must be open to fill the boiler. See attached image.

Doesn’t sound like your builders sub contractor has done anything wrong here.

 

[Welder]

Don't blame you for keeping it. I'm keeping my Glow Worm Ultimate going for as long as I can.

We've taken condensing boilers out which have been 6/7 years old which were beyond repairing. Admittedly these were probably ones that haven't been well maintained or fitted well.

My Ideal Mexico is of 1997 vintage

On a sep note, efficiency ratings as specified by all manufacturers are ONLY seen by a VERY small number of UK home owners.
Why?
The efficiencies are calculated at a flow temp of 50 degrees C and a return of 30 degs C. However, most UK home owners would claim the system is faulty at such low flow temps so new (efficient boilers) are commissioned to run at a flow of 70 & (at best) a return of 50. This delivers just a few % of potential and rarely (if ever) pays back the investment.

 

[OffshoreGas]

My Ideal Mexico is of 1997 vintage

On a sep note, efficiency ratings as specified by all manufacturers are ONLY seen by a VERY small number of UK home owners.
Why?
The efficiencies are calculated at a flow temp of 50 degrees C and a return of 30 degs C. However, most UK home owners would claim the system is faulty at such low flow temps so new (efficient boilers) are commissioned to run at a flow of 70 & (at best) a return of 50. This delivers just a few % of potential and rarely (if ever) pays back the investment.

How do you achieve that then?

Increase the resonance time/reduce flow rate through radiators?

Surprising in this day and age of smart TRVs there not measuring flow/return temp.

 

[Welder]

How do you achieve that then?

Increase the resonance time/reduce flow rate through radiators?

Surprising in this day and age of smart TRVs there not measuring flow/return temp.

Achieve what?

 

[OffshoreGas]

Achieve what?

The temperature differential across the radiator.

 

[Welder]

The temperature differential across the radiator.

Flow rate. Slower the flow rate higher the temp drop.

 

[Michael1960]

If I accept what you are saying and I bow to your superior knowledge. I don't need to call the builder back. I just need a competent Gas Safe plumber to investigate and fix the problem? Know any good and qualified trustworthy central heating engineers in the North West London area?

The emphasis being "plumber" or heating engineer !

 

[OffshoreGas]

The emphasis being "plumber" or heating engineer !

If you read the manual it says the diverter valve needs to be be open to fill. There doesn't appear to be anything wrong with the work tats been done.

 

[Chrisjones.7976]

If the cold water feed to the filler loop is boiler side of the new valves you should be able to pressurise the system. It's unclear what's where from the pictures. It needs a sketch of the pipework with valve positions. If you turn a tap into you get hot water? Too much guesswork without a diagram.

 

[OffshoreGas]

If the cold water feed to the filler loop is boiler side of the new valves you should be able to pressurise the system. It's unclear what's where from the pictures. It needs a sketch of the pipework with valve positions. If you turn a tap into you get hot water? Too much guesswork without a diagram.

The manual for the boiler clearly says the the diverter valve needs to be open to fill.

 

[Karl Murray]

Get someone out to check it?

No point any of us guessing as by the sounds of it you shouldn’t be touching it anyway.

Regardless looking at your pictures you don’t have a bypass for when both zones are closed. Who knows if you’ve got a non return anywhere on the system.

You’ve also got a combi so hot water demand isn’t with the zone valve.

You’ll need a professional to diagnose on site it in my opinion.