Ed Sirett wrote:
On Mon, 08 Jan 2007 16:50:02 +0000, Richard Walker wrote:

Hi

Few years ago I bought a 2kW petrol generator to keep the home running
when the mains power failed. Used several times, no probs except that
the CH boiler locked out when the generator was switched in. A reset and
all worked fine.

Last week had another power cut but this time the CH boiler locked out
after about 30 secs even after re-setting (several times). Everything
else in the house works OK, including gas fired Rayburn cooker, which is
just the same sort of technology as the boiler.

Any thoughts on what is upsetting the boiler? -it's a normal wall
mounted balanced flue unit from Vaillant.

Thanks

What arrangements are used to switch over the suppies.
What arrangements are used to earth the installation?
A polarity problem is centre stage here, especially if the gas lights but
then goes out after a few seconds.

Thanks, Ed

The gennie is switched in with a dp change over switch which isolates
house from grid supply then switches gennie power into house. Normally
switch boiler off at its isolating switch before switching in gennie,
then switch boiler on when gennie has settled down. House is earthed as
normal, gennie chassis is connected to house earth but not separately
earthed.

Supply from generator is clearly lumpier than mains - a discernible
flicker to lights. Might this be the problem? And if so, I wonder why it
used to work but doesn't now?

Cheers
--
Richard