New gas pipe fitted, but gas won't ignite?

Question

I’ve had a plumber fit in a new gas pipe into my house. The whole run from meter to kitchen in copper, as my prevouis pipe was illegal.

The plumber said he had difficulty re-lighting the boiler after fitting the pipe. I know that my boiler can be temperamental sometimes.

Anyway I tested my gas hob in the kitchen and I get the problem below.

I turn on the hob. I can hear the hiss of gas, but I can’t ignite the gas. Could this be oxgtyen in the line. The gass has been turned off for 6 weeks.

I have spoken to the plumber and he coming around Monday to investigate, but he said he had pressure flow tested the new pipe so should ignite ok.

What can this be? Just for my info really. I am hoping to assume the plumber will know what the problem is.

Answer 1

The problem here is after the repair was completed he should have done a purge to do his initial test light to check for operation. Guessing here he made the repair turned the gas back on, so air was still in the line, and now you the home owner cant get it to light.



Turn gas valve to pilot bleed air for 30 secs try to light. If no ignition wait 5 mins so excessive gas can dissipate, try pilot again and relight.



If it wont light after two or 3 attempts, you stated it can be temperamental, so if you have a thermal couple in the gas valve the thermocouple maybe faulty and its not seeing the flame so it wont stay light. Then sometimes it may. Check and replace thermocouple.

Answer 2

I would say that David C is on the money, but this is school yard stuff for a gas safe registered plumber, I would be concerned about the work you've had done if the plumber doesn't even know how to purge a new gas pipe.

Answer 3

You need to purge the air out of the line.



Keep the kitchen well ventilated.



Open main gas burner on full for 15 seconds. Close the burner and allow the gas to disperse.

Try and light the burner.

Repeat above until burner lights then allow burner to run for a minute or so until

there is a steady good flame.



You may find that your boiler will now light correctly.

Answer 4

Is this the same guy who said your gas pipework was illegal ?

Are you sure he's GasSafe registered ?

Something not quite right about this guy not doing an air purge to get the appliances up and running.

Answer 5

Check to see if the gas lever is open fully by your gas meter. If its try bleeding it through your hobs for 5 - 10 secs. If that fails i expect there is a valve shut some where or you may have a leak.

Answer 6

Purge air! Not you gas fitter but it is a basic error if that had not been done.

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