Hi,

I'm having problems with my venerable but previously reliable Netaheat
MkII 16/22 boiler. Looking through the previous very useful postings it
seems as if the Spark Generator is failing, but I thought I'd ask here for
confirmation.

The boiler starts up okay from cold, and runs through a few on/off cycles,
either via the room stat or it's internal stat, but eventually it won't
relight.

When it ends up in this state, the air fan is running, the pressure switch
has detected this and the spark unit has 240v across it, but there is no
spark clicking away. However, the unit must have produced a spark minutes
ago to have lit the boiler previously.

Other than fit a new SG (approx £30 online, so not too bad) is there
anything else to check ?

I've tried starting from cold with the gas switched off (to check that the
thing will produce multiple sparks), and I've opened up the SG case but
there's no obvious signs of component failure. Maybe the capacitors have
dried out or something and it fails after being powered for a few minutes ?

Any comments approciated,

Cheers,

Phil Young

On Wed, 26 Oct 2005 17:18:32 GMT, Phil Young
wrote:

Hi,

I'm having problems with my venerable but previously reliable Netaheat
MkII 16/22 boiler. Looking through the previous very useful postings it
seems as if the Spark Generator is failing, but I thought I'd ask here for
confirmation.

The boiler starts up okay from cold, and runs through a few on/off cycles,
either via the room stat or it's internal stat, but eventually it won't
relight.

When it ends up in this state, the air fan is running, the pressure switch
has detected this and the spark unit has 240v across it, but there is no
spark clicking away. However, the unit must have produced a spark minutes
ago to have lit the boiler previously.

You need to check visually whether a spark is occuring at all. This
may not be completely visible through the viewing window.


As a seasoned gas man I would use a multimeter connected to the gas
valve pilot solenoid. I'd then remove the gas,initiate the start up
sequence,when the spark gen starts I'd observe the pilot block
directly for signs of spark and also check for 240Vac at the pilot
solenoid. If there is 240Vac and no ignition,id manually light the
pilot with a match to check for gas flow. If it does light,then you
need to investigate the spark gen its lead and probe. If it doesnt
light,the gas vavle could be duff or there could be a blockage between
pilot gas outlet on valve and the pilot burner.

I'm not suggesting you do this yourself as there are dangers for the
uninitiated !




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On Thu, 27 Oct 2005 12:45:40 +0100, tarquinlinbin wrote:



You need to check visually whether a spark is occuring at all. This
may not be completely visible through the viewing window.


As a seasoned gas man I would use a multimeter connected to the gas
valve pilot solenoid. I'd then remove the gas,initiate the start up
sequence,when the spark gen starts I'd observe the pilot block
directly for signs of spark and also check for 240Vac at the pilot
solenoid. If there is 240Vac and no ignition,id manually light the
pilot with a match to check for gas flow. If it does light,then you
need to investigate the spark gen its lead and probe. If it doesnt
light,the gas vavle could be duff or there could be a blockage between
pilot gas outlet on valve and the pilot burner.

I'm not suggesting you do this yourself as there are dangers for the
uninitiated !




Remove antispam and add 670 after bra to email

http://www.no2id.org/

Thanks for all that, I've done something similar whilst investigating.
Removing, opening and replacing the spark unit seems to have sorted the
problem, so maybe it was just a dirty connection somewhere. I can't
understand why everything worked okay for a few cycles and then failed
though. C'est la vie.

--
Cheers,

Phil Young