Smell of gas on new Baxi Barcelona install

[Rick Hughes]

I have installed a new boiler - part of UFH for a new house build, it's a Baxi Barcelona.

I had a Corgi guy make the primary & the gas connections , plus gas soundness tests &commission & that way got the safety cert. There was a distinct 'whif' of gas/exhaust fumes, especially on start up.

The guy has come back and checked all connections, and carried out a second gas leakage teat - form the meter, so whole circuit is tested .......... all sound.

The problem is 'less' pronounced, but when you enter the house when it has been shut up for a time (not yet living there - heating is on low tickover) there is a definite odour of gas in the boiler room, low level but there. It still seems to be related to start up cycle of the boiler.

All flue & fan connections have been checked, there was originally one of the fan fixing wingnuts missing - which Baxi refused to supply FOC, I had to order form a spares company (not good after sales service !).

Anybody any experience of this with a Barcelona ? ...

Rick

[John Stumbles]

I'll leave others to pronounce on the quality to be expected from "Poxi-Batterton" condensing boilers (your cue, Ed :-)

You are sure it is gas you're smelling, not a rather smelly flue gas getting back into the room, aren't you?

If the pipework from meter to boiler is sound but you get a smell of gas while the boiler is running it suggests a leak from the gas valve or elsewhere in the boiler, after the part of the valve which only lets gas through when the boiler is running and is therefore not tested by a tightness test.

I suggest a call to Transco (0800 111 999 or is it 999 111?) and when/if they designate the beast Immediately Dangerous and cut it off you then call Poxi and share with them the good news.

-- John Stumbles

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[Andy Hall]

Didn't we have a couple of instances of this with these machines before Christmas due to the cap on the condensate drain being loose or split?

.andy

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[Ed Sirett]

I think these boilers are the 'saniflow' of heating.

If the gas is sound to the valve then the only place gas can escape would be within the 'room-seal' chamber. There is plenty of scope for gas to folow its _own_ route therein. It comes along a pipe which is a light push fit in the end of the fan intake venturi and secured by one small set-screw. Howeve gas escapes would need to get into the room and I can't see that happening in quantity.

I think it is likely that the drain plug on the trap is leaking (not so likely with brand new). Quite possible is that the trap is empty and the condensate drain pipe has come adrift?

As I've have posted before these boiler don't seem to make condensate except at start-up.

Or there's a big fault with the flue installation.

[Andy Hall]

I wondered when somebody would make the analogy.

Isn't one supposed to fill it with a jug of water during installation?

.andy

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[Ed Sirett]

For sure. However the trap is not always deep enough to retain the water against the fan. 8-;

[Rick Hughes]

The Flue is right, and there is a large amount of condensate on start up ... but nothing during main burn.

I've borrowed a can of spray on leak sealer so will have a go with that tomorrow ...

I had no prior dealings with Baxi ... previous boilers have been Stelrad, the baxi was recc by the UFH company (they didn't supply so no incentive form that side)

I'll take a close look at the condensate trap tomorrow.

The only othersymoptom is that occasionally it can be quite noisy when at the satrt of the main burn ... first minute or so almost a bubbling/rattling sound ... but not every cycle, maybe once or twice a day.

Rick

[Andrew Gabriel]

If the condensate pipework joins a sink or bath drain, then emptying the sink or basin might suck the trap empty. I have this situation, and used a trap with an air admitance valve on the sink. However, I didn't actually try it without this to see if it was strictly necessary, but when the basin finishes emptying, the air admitance valve certainly operates.

Actually, it surprises me that I've seen no warnings about this in any of the condensing boiler installation instructions I read.

[Andy Hall]

Does the condensate drain go directly to the outside or into some internal drain? If the trap is emptying for some reason, fumes will come out of it. This might be an explanation as to why the smell is occasional.

Some condensing boilers (I don't know about this particular one) vent a small amount of unburnt gas at the start of their ignition cycle under some circumstances. Is it possible that this is happening and coming into the house through a vent? The smell additive, methyl mercaptan, that is put into natural gas to facilitate its detection is detectable by the nose at extremely low concentrations. If the house is more or less shut up, perhaps this could be hanging around.....

Obviously this needs to be investigated and fixed, but the causes might be quite broad.

.andy

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[Andy Hall]

I suppose that if the connection is on the smelly side of the sink trap, the fumes would not come out of the sink, but there could be a case where there are two sinks and one sucks the other and the boiler trap.......

I got round this by making use of a washing machine trap with 40mm upstand. I cut in a 40mm tee to the upstand pipe which means that there is an air break because the washing machine hose drops into the top as normal. Into the tee went a 40x32 and a 32x22 solvent weld reducer. Into that went Osma solvent weld overflow pipe with a 135 degree bend and then another nearer the boiler to take the pipe vertical. The angle prevents washing machine water from entering the

22mm pipe. As belt and braces, under the condensate drain outlet of the boiler I fitted a tundish. This means that I can also see the reassuring trickle of condensate as the boiler runs.

.andy

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[Ed Sirett]

That might be that this is the only boiler they have experience with? I myself suffer from a certain amount of conservatism when recommending manufacturers since I prefer the devil I know to the ones I don't. I would have to admit that if the only condensing boiler I knew was the Barcelona I would have a dim view of condensing technology.

It could be some sort of flame instability. I would suspect that the combustion might not be correctly adjusted. It might be the condensate trap being blown through?

[Rick Hughes]

It goes directly outside ... I did check the trap inside the boiler ... all is well.

Success though, the leak detector spray showed up a minute leak on the 15mm compression side of the gas c*ck on the boiler. Called back my Corgi guy ... he did something I have not seen before but he advises is common practise. With olive in place he wound some PTFE tape over the olive and the first couple of threads of the fitting. His view is that the PTFE lubes the threads and allows it to tighten up, but is not providing the seal the olive is still doing that.

Anyway ... it did the trick and cleared the leak.

Interesting that 2 tests with his gauge failed to show this leak ... assume that it was not being left long enough for such a small leak ?

Rick

[Ed Sirett]

Alas, this guy is giving the rest of us a bad name...

This is not the way. Around the olive would have been better, a bit of boss white would have been better still. The gas pipework should have been tested for soundness with the boiler c*ck open to include as much as possible of the boiler in the test.

This would then have shown up the compression joint as leaking much earlier and saved at least 2 extra visits.