3 millibar leak from Worcester 35CDI Combi Boiler, sounds expensive

[swebb99]

I had a plumber around yesterday who fitted a new radiator and also blanked off an old gas cooker gas pipe. He did a pressure test on the gas system and found the pipe system was leaking 0.5millibar which he said was not an issue but the carcass of the boiler was leaking 3 millibar gas. He could not work on the boiler at all so I need to get a registered company to investigate.

Would I be correct in thinking that 3 millibar is not a massive amount in the boiler but needs sorting and if so is it likely that it would be the value. I dread to think how much it may cost to repair

Cheers

 

[Madrab]

Erm, get a GSR in immediately to test it properly. Any gas leak is immediately dangerous and potentially fatal.

If what you write is what he has said then it needs isolated and looked at yesterday. A little confused about him being able to blank off the pipework but can't look at the boiler or at least ask permission to isolate it till someone can look at it, unless he shouldn't have been touching it to start with.

 

[swebb99]

Yes I turned the gas off. He didn't have the certificate or whatever it is to open and do work on the boiler but is allowed to check the pressure. Not sure of the rules. In short he didn't open the boiler but could detect it was leaking. He also had some kind of gas sniffer which he used all over the house and the only time it went off was when he placed it near the vent/flue of the boiler.

 

[Madrab]

Unless he has a Gas Safe Registered licence then he's not allowed to work on gas at all. If he has one, then ask him for his number and then you can check at the GSR website, either that or on the back it will state what he is allowed to work on. Always worth checking credentials before any gas work is done.

Re your original post, any ideas on here would be pure conjecture and could constitute gas advice and as such not allowed, a GSR should be able to tell what the issue is.

 

[swebb99]

Ah ok thanks. I didn't realise that no advice could be given on Gas. My main concern was just looking at pics of the boiler on web it all looks incredibly complicated and was worried I could be looking at thousands to sort out, however if there was a common issue maybe that wouldn't be the case.

 

[ianmcd]

I think you might be confused as to what he actually told you I think you have a 0.5 millibar gas leak on your system but a 3.0 millibar pressure drop between the gas meter and the boiler this is not a gas leak it means the pipe to your boiler is too small, if you are in any doubt call 0800 111 999 and they will test it for free but be aware they will probably just turn every thing off and tell you to get a registered gas engineer to sort it why dont you call your plumber back and ask him to clarify what he told you

 

[swebb99]

Yep good idea, I've obviously not understood something.

 

[ianmcd]

To let you understand , the regulations say that you should not have more than a 1 Mb difference between the supply from the meter and any appliance, the gas meets a resistance through the pipe and fittings etc so the working pressure at the meter and at the appliance always differ, your boiler at 35KW is a large appliance and if it was fitted to replace an older boiler which would almost certainly not have been such a high output boiler and they used the existing gas pipe then that is where the problem came from, if it is just a 3 Mb pressure differential and you are happy with your hot water then just forget that he told you anything its nothing to worry about with that boiler

 

[swebb99]

Ah OK thanks for the reply, I must have miss understood because I thought he was saying that there was a gas loss in the system and his sniffer went off when he placed it around the vent on the outside wall. I'll have another chat with him now I'm armed with a bit more info

 

[Agile]

It is quite likely that he had a limited scope registration.

For example for just gas meters.

But did not have the module required for boilers.

Or possibly was not registered at all ( any more ) and was just working slightly out of scope by blanking off the cooker supply. But he obviously knew what he was doing and was correct not to investigate the boiler.

It may be a loose gas connection in your boiler or the gas valve is leaking.

The boilers only cost £1000 and not "thousands" and last Worcester gas valve I replaced came to a total of about £240. In any case the makers will do fixed price repairs for about £300.

But as said you need a gas safe registered engineer to investigate for you.

Tony

 

[ianmcd]

Ah OK thanks for the reply, I must have miss understood because I thought he was saying that there was a gas loss in the system and his sniffer went off when he placed it around the vent on the outside wall. I'll have another chat with him now I'm armed with a bit more info

You are drip feeding us information by the vent do you mean the flue terminal ? if this is the case it is possible that the multifunction gas valve inside you boiler is letting by and will need replaced immediately, if this is the case do not use it untill it is replaced

 

[swebb99]

Sorry not meaning to drip feed, just that I know as much about boilers as I do about the Apollo Lander And thanks for the info Tony that has put my mind at rest somewhat.

 

[simond]

The gas transporter won't be particularly interested in a 3mB drop across the carcass at full modulation. Neither will they be interested in a 0.5mB pressure drop - unless you can smell gas.

If it worries you and you can't smell gas, you will need to get in an RGI and expect to pay, of course.

 

[swebb99]

I'm not even sure what 3mB on the carcass equates to, are we talking enough gas to keep something like a pilot light going or is it less or more than that?

 

[Dan Robinson]

3mbar on a boiler carcass is next to nothing. Still needs sorting.

All these things are relative to the volume being tested.