In message .uk, Ed
Sirett writes
On Sat, 01 Nov 2003 17:21:50 +0000, a_mcbride wrote:

My ideal elan 2 50FF was failing to ignite automatically having checked it
over for loose connections I switched the electrics back on and it still
failed to light. Whereupon I decided to put the bottom plate which is just
really to prevent anything from getting into the electrics it wouldn`t quite
fit so I had to be rough with it and accidentally knocked the side of the
boiler, whereupon the boiler started clicking and fired up. Now the boiler
lights but after a short time anything from 10 to 30 minutes it fails to
ignite but the fan still runs if I give it a thump on the side casing then
the injector fires up.

I have also noticed that the downstairs radiators are not getting as warm as
the upstairs which seems to me to suggest that my pump (13 years old) is
failing. Could this also be related to the problem with the ignition? Maybe
the flow rate is not sufficient and the boiler is refusing to light for
safety reasons. Or is it some other problem perhaps with the Honeywell gas
control?

Love to solve this with a technical solution rather than a thump on the side
of the boiler.

Responding to other posts:
If the flame sensor sees no flame the boiler will lock out or at least
repeatedly try to reignite.

The Elan has a Stelrad 7B pcb inside. It is a fairly primitive
electronic ignition and has no lockout capability, it just keeps on
sparking. It is very prone to the fan control relay going high
resistance (before it melts and sets fire to the pcb). The soldering on
the connectors on the pcb usually tends to be OK, but there could be a
problem with a look wire making intermittent connection with the
connector pin due to breaking.

The OP didn't say whether the fan was working or not. So there could be
a problem with the APS or pcb or both


If the casing is not sealing 100% as it should it can be that a draught is
set up which hinders or enables ignition to take place. Ignition should
take place when the casing is proerply sealed.

With ignition problems it is important to divide the problem into smaller
ones.
Where are the sparks?
No sparks = Electric or Electronic Problem/ Failure with something else
like the air
flow or its switch/ dead short of HT leads.
Sparks in the worng place: poor insulation on the high tension leads,
electrodes worn in the wrong place.
Sparks in the right place: no gas!, dirt and crud stopping ignition.

The OP may just as easily find that the knock to the boiler disturbed the
air-flow switch as that there is a real problem with the ignition.

The key test is when the knock happened was there initally a big click
from the gas
valve (problem is not with the ignition) or did only the ignition sparker
start to be heard.

HTH


--
geoff