My hot water smell of gas - Vaillant ecoTECH Pro

[cattie24]

Hi,
I'm worried about a new Vaillant ecoTEC pro 28 installed about a month ago. Everything is working fine except I can sometimes smell gas from the hot water taps when I start to run them. I thought perhaps I was just me, but this morning my builder turned the hot water on and said he could smell gas.

I've called the installer and he came quickly when I explained that the hot water smells of gas, but he couldn't smell anything (an neither could I) when I turned the tap on to demonstrate. He said that he's never heard of gas getting into the water.

Then the builder went to get materials and bumped into a plumber friend. He thought he had heard of a fault with Vaillant boilers, where a hole in the combustion tank can suck gas into the hot water but once the tank warms up it seals itself. Could this explain why the water didn't smell gassy when the installer came round?

Has anyone else heard of a problem like this with Vaillant boilers? I'd be really grateful for advice.

 

[gasmarc]

if the installer has checked it out and it is still there call vaillant out as it is a warranty issue

 

[cattie24]

Thanks Gasmarc. I have rung Vaillant (60p per minute) and they told me to call the National Grid to test the gas suppy, which I've done but they found nothing. Should I mention the theory about the hole in the combustion tank next time I ring?

 

[SafeGasInstall]

turn power supply to boiler,run cold tap and take a reading on the gas meter .......and take it from there !
😛

 

[Blackcatgas]

I cant see how gas at 20 mbar can permiate the hot water @ 2.5 +bar I dont belive it, more likely somthing in the supply like a rubber tap washer reacting to scalding water.

 

[gasmarc]

water can get into the gas which i have had before but never the other way around

 

[cattie24]

Hi SafeGasInstall, not sure I understand. Should I turn boiler off, read gas meter then turn on cold tap and re-read meter? I only smell gas with the hot tap.

 

[Billy Bob Bob]

this is what's probably happening,the condensates been taken into the sink waste,run the hot,trap/seal being sucked out of the boiler,p.o.c.s being smelt through the sink waste

 

[gasmarc]

I like that lol

 

[Blackcatgas]

I like that lol

Mee too, never thought of that.

 

[cattie24]

Wish I understood. No change in the gas reading. Think I'll try again tomorrow when it's cooled down. If it is a hole that seals itself when the boiler heats up I'm not going see or smell anything now that heating's been on all day.

 

[Blackcatgas]

Is it just smelling at 1 tap? is it the tap thats in the same room as the boiler?, I like Dans Explanation the best, I dont agree with the builders prognossis about a hole thats seals itself up.

 

[Billy Bob Bob]

basicly a small 21mm pipe goes in to the waste system connected to your sink,run the water though it on the hot and it siphons the water from your boilers condensate trap, creating the smell,put this to your installer or direct him/her to here

 

[gasmarc]

is it only from the one hot tap ? ,for what its worth i think it would be impossible for the gas to get into the water because if there was a hole the pressure of the water would get into the gas valve and stop the boiler working altogether

 

[Reg Man]

Like the reasoning, but there is probalbly a trap on the condensate waste and POC's are not normally pushed into the waste system if operating properly. Has a redundant gas pipe been used during the install to convey the hot water? Have seen this done before.

 

[gasmarc]

yes that could be possible knowing the way a piece of old gas barrel can smell

 

[cattie24]

All the hot water taps are affected, bath, basin and kitchen sink. The builder noticed it after plumbing in the new sink in the kitchen, as I hadn't mentioned it to him I got worried at this point as he said it's not normal for the hot water to smell of gas. It's just a wiff that then goes away as you run the water. I don't notice any smell after the heatings been on for a while, hence the problem demonstrating to the gas engineer who thought I was smelling chlorine.

Thanks for all you sugestions, I'll keep testing. Wonder whether it would help if I can capture some of the smelly water?

 

[plumbster3456]

gas coming out your taps lol never heard of it before have you got water coming out your cooker ? if not then there aint gas coming out your taps

 

[cattie24]

Hi Gas Man,

Do you mean the small grey pipe for the condensed water that comes out of the bottom of the boiler? I think I understand what you mean, that some gas is emitted with the condensate and this enters the drain and then travels back up through the sink over flow?

However the condensate goes into a brand new separate drain to the waste from the sinks. This branch drain joins the main drain downstream in the garden about 20 feet down from where the kitchen and bathroom waste enters.

Do you think the gas could travel all that way back up?

 

[gasmarc]

as i said before water can get into the gas but I have never heard of the other way around, when i said call vaillant I ment to get them out to confirm the problem is not boiler related

 

[shorticus]

Long shot; does your kettle smell when warming up?

 

[Billy Bob Bob]

Hi Gas Man,

Do you mean the small grey pipe for the condensed water that comes out of the bottom of the boiler? I think I understand what you mean, that some gas is emitted with the condensate and this enters the drain and then travels back up through the sink over flow?

However the condensate goes into a brand new separate drain to the waste from the sinks. This branch drain joins the main drain downstream in the garden about 20 feet down from where the kitchen and bathroom waste enters.

Do you think the gas could travel all that way back up?

no sounds like thats not the problem

 

[cattie24]

Hi shorticus,

No there's no smell from the kettle.

 

[shorticus]

Hi shorticus,

No there's no smell from the kettle.

Just thought there might be some kind of water contamination with the smell released when heated. I for one am a bit baffled to be honest

 

[shorticus]

Cattie24, have you sorted your problem? I for one am dying to know!

 

[SafeGasInstall]

same here !!!!please give a up date A S A P !

 

[cattie24]

Hi, no sadly haven't solved it yet. I've had a think about it and talked to the builder again. He's adamant that he can smell gas, but the condensate drains into a separate branch of the sewer from the waste for the kitchen and bathroom. He also thinks it unlikely that an old bit of gas pipe was used for hot water.

My boyfriend thinks that it may be normal for hot water from combi boilers to smell.

I've been observing it for the last week and it seems to be noticeable only if I haven't had the heating on, so when the boiler is warm there no noticeable smell.

I'm not sure what I can do next because when I rang Vaillant or British Gas Homecare, they wanted to call out National Grid as soon as I mentioned I could smell gas in the water. But the National Grid guy couldn't find any evidence of a leak or offer an explaination. My installer told me that gas in the water was a physical impossibility because of the pressure differences, and suggested I call out the water company, but I'm not going to do this as my cold water doesn't smell and the hot water has only been smelling since the new boiler was installed.

The builder remains convinced by the idea that there is a fault with the boiler and it has a tiny hole in the combustion tank.

So I'm stumped but hoping I can find an answer while it is within warranty!

 

[gasmarc]

no that is highly unlikely ,i wonder if you could get a water testing kit which would eliminate things

 

[mikegas]

would a gas sniffer at the side of the running water detect the gas if there was any present?

 

[hary_j]

Just a quick one, the pipe work leading to the tap hasn't previously been used for any sort of gas usage before has it?..

previous smells can come through it with warm water, it some time can be the case but not always..

If the builder is really adament that it is the boiler itself at fault and nothing to do with the Installation side, then i would make sure the combustion tank he is talking about is changed or infact the whole boiler,

personally i think you've got real unlucky with the boiler itself out of the 100,000s sold it had to be yours.

Talk to vaillant again and tell them to come and check again if not you will be reporting to Trading standards.

 

[gasmarc]

or a lighter or piezo perhaps,

 

[hary_j]

would a gas sniffer at the side of the running water detect the gas if there was any present?

Sniffer, lol! You mean leak Detector..

 

[gasmarc]

turn the power off to the boiler and run the hot water and see if there is any movement on the gas meter

 

[Billy Bob Bob]

sniffers what my leak detectors called as well not that i use it much ldf dont lie but a sniffer gets excited over all sorts

 

[mikegas]

lol true, but mine found a leak on an old cooker point last week that had been covered by a kitchen unit, wouldnt of found that with my ldf so they have there uses