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Gas Work

New boiler and new gas pipe

Boiler (heat only) is broken. Getting new one and plumber has advised that he may need to redo gas pipes from gas meter. Says he will only know once boiler is fitted. Reason given was that he needs to run max test with new boiler and it might give a low pressure reading which could lead to a gas safety hazard in future. He did say it was unlikely and also said a real problem was unlikely, but regulations mean that boiler might fail a safety check in future if there is low pressure and he doesn’t change pipes. Current boiler pressure was fine (I assume), so don’t really understand why this might be a problem or why he can’t tell before starting the job whether we are likely to have a problem. Says he will only be able to tell on testing after installation. Does this sound legit?

6 Answers from MyBuilder Gas Engineers

Should be able to work out pipe size needed now just need to know what kw new boiler going to be and kw of any other appliances that are part of the installation. Bit of maths and he can work out what the pressure drop across the installation would be .


Answered 13th Nov 2020

Agree with Wayne, You can work pipe sizing prior to boiler install so you can price the job ahead of work. Most new boilers will require min 22mm pipe. There is pipe length and all the fittings to be calculated as well. If you got 15mm pipe now it is no brainer, you need new larger pipe.


Answered 13th Nov 2020

If the installers are using a boiler of a higher kw or the exsisting boiler was non condensing this would make a difference as condensing boilers tend to need higher gas working pressure. There is always the possibility that the gas run was undersized originally but I would have thought the installer checked this with a gas rate


Answered 13th Nov 2020

Hi in my opinion it depends on how many gas appliances you have,the gas pipe coming frome the gas meter should be able to allow all appliances to run at the same time without any complications eg, not causing an appliance to cut out, the replacement boiler you are having should say what the kw is engineer fitting it should know weather the existing gas pipe is acceptable by doing the calculations needed.


Answered 13th Nov 2020

Utter horseshit. Could calculate the correct size before undertaking the install


Answered 13th Nov 2020

If he knows what his doing he should know just by looking at it and make his judgement as things stands.
Just do pipe sizing then you will get the results.


Answered 15th Nov 2020

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