On Sun, 04 Apr 2004 15:30:21 +0100, John Stumbles wrote:

"riverthames" wrote in message
om...
The permananet pilot light on my Puma 80 lights ok when holding in the
gas valve and sparking the piezo but it goes out when slowly releasing
even after a few minutes. Water pressure is above 1 bar.

Changed the thermocouple but the effects are the same.

Is the pilot flame actually enveloping the thermocouple when it's
alight?

This boiler is a fanned flue unit with permanent pilot light, a number of
manufacturers had this designs (SD, Vokera, Pott. Puma...).
It is essential to check the fan still operates at low revs when the
boiler is idle. It is possible to get fans which stick (but are otherwise
fine at full power) eventually the oxygen gets consumed in the combustion
chamber and the pilot goes out. I used to think there ought to be enough
incidental draughts to keep the pilot going but that is not the case.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html