Hi, I have a cointra gas water heater which is very tempromenta,l sometimes when the hot tap is turned on it lights the burners no problem but more often than not the pilot light dies as the tap is turned on,I have changed the thermocouple but to no effect can anybody help?

Cheers graham

What is happening is when you turn on a hot water faucet, the heater is calling for hot water. When that happens, the burner in the heater is supposed to light from the pilot. The pilot assembly could be bad,, the flame is either too low and the orifice is clogged. You did not mention the type of gas being used. LP burns very dirty and will eventually clog the orifice. I would change the pilot assembly, relight it and try it. If you don't want to attempt that yourself GAS IS DANGEROUS, call a service man to check the gas pressure and have them change the pilot. The last and probably the least likely is that the regulator is bad. Good Luck.

Hi Handyman,
Thanks for your quick response the pilot assembly is a sort of spout shape with the pilot light divided into three, 2 of the flames face up toward the burners and the last one runs runs down the side of the spout and finally ends up as a small all blue flame encompassing the thermocouple which has a shield over the top of it which I imagine is to make sure the flame is deflected onto the thermocouple, the 2 larger flames appear mainly blue with the top 1/3 yellow and the gas is butane (im in Spain) I have cleaned the jet with compressed air and the pilot assembly so I'm running out of ideas.

All help greatly received
Many thanks graham