Gas smell from boiler when it switches off.

[J_N30]

It might be worth looking at a service contract with the likes of British Gas or SSE. They have a one off repair cost and I'd imagine the annual subscription would be less than the £300 you've already spent.

Having said that if it's a design fault then they probably won't cover it.

 

[ianmcd]

It might be worth looking at a service contract with the likes of British Gas or SSE. They have a one off repair cost and I'd imagine the annual subscription would be less than the £300 you've already spent.

Having said that if it's a design fault then they probably won't cover it.

SSE surely you are having a laugh

 

[Restoration man]

One point I need to clear up re condensate pipe runs etc.

The boiler has been fitted for 5 years. This smell has only happen since it was serviced 5 weeks ago. It was a routine service but the sump was removed as it had dripped for a long time. Apparantly a design fault.

Since this when we go into the washroom after the boiler has been switched OFF by the clock it stinks.

 

[Restoration man]

The smell is only ever present when the boiler goes OFF. It never happens when the burner goes off because everything is at temp but the boiler is still at C. Call for heat.

What's different functionally in the boiler between OFF and C with the burner off?

Thanks

 

[Agile]

Are you unable to tell us where the condensate outlet goes to?

Tony

 

[J_N30]

SSE surely you are having a laugh

They do a service contract if I'm not mistaken.

 

[gas112]

there is no difference from boiler going off at clock to boiler going off at stat satisfied .
As an FCO although a lot of people think its just tofo .
Most guys i know once they have tested installation and found it to be sound with customer saying they can smell gas in these circumstances would be going over the boiler both whilst on and off with there leak detector which is far more accurate and sensitive than any a standard RGI would have as they are calibrated everyday and if its the old style at a maximum of 28 days and even if it was going 5 ppm (miniscule leak) which is well below what the human nose can detect it would show up on their machines and they would then inform turn off and give paperwork

 

[ianmcd]

They do a service contract if I'm not mistaken.

They certainly do but I would trust my dog to repair a boiler before I would trust them

 

[Restoration man]

Regarding the condensate pipe. I have sink and dishwasher which then runs along to washing machine and down into cement floor where it meets toilet waste and away it goes. The condensate is piped into the waste near washing machine. This is all in plastic and internal. 2 inch waste and toilet waste are original from 80 years ago.

We renovated washroom 5 years ago and it's only since recent service 5 weeks ago this has been an issue.

I agree things can change but the set up has worked and not given us this smell issue for nearly 5 years.

Thanks

 

[Restoration man]

there is no difference from boiler going off at clock to boiler going off at stat satisfied .

If above is the case (thankyou)

We never have the smell when the boiler stops due to water tank reaching temp or rads reaching temp or room stat switching off. It's only ever when the boiler has been switched off by the clock and we go into the washroom. Worked out with the wife that the smell is probably worse if we've gone in after 30 mins to an hour ish.

Basically it needs time after the clock has timed the boiler off to obviously leak into the room.

I'm now thinking the boiler cycling keeps the fan going and removes any smell.

 

[HERTS P&D]

Try cleaning the over flow on the sink.

Andy

 

[Restoration man]

Once we establish the smell is there again. I open the door and window for a couple of mins then it's gone. So it's as if there is a final pocket of gas left when the boiler switches off. It isn't removed by the fan and leaks into the boiler casing and then the room.

Sounds like there would have to be a few failures for this to happen which is maybe why everyone is stumped.

 

[GuessMan]

I think I may have the answer; is this a heat only boiler? and has been wired up with 3 wires only? i.e. when the clock switches off does the display go off as well? This would mean there is no post purge of the boiler.

If this is the case do not worry, it is not a preferred installation, but acceptable. Any trace of gas will be well within safe limits.

Well that's my guess anyway.

 

[Agile]

If this is the case do not worry, it is not a preferred installation, but acceptable. Any trace of gas will be well within safe limits.

A friend has a boiler installed under a scheme like that. She asked me to service it for her.

I asked Vaillant Tech about it. He said they do not advise it and would not cover it under the warranty!


In this case we think it is drain smells!

You suggestion would explain why its only smelt when going off at timeclock.


But the boiler should have a full trap fitted which prevents smells being sucked into the boiler.

I would be checking condensate connections near boiler and trap.

Suspicious the sump was replaced at last service!

Tony

 

[GuessMan]

Full of it as usual, the latest boilers from Vailant can be wired 3 wire and will be under warranty. They are the ones with the aluminium heat exchangers. Ideal say all Logics are ok and will be covered under warranty. Glowworm Energy can be 3 wire and will be under warranty. Baxi Eco Blue Advance were designed for it, so will definitely be covered under warranty.