geoff wrote:
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

The fan continues to work when the pilot light is not alight. Have a spare
PCB due to previus problem but same fault occurs with a different PCB. Have
had a look at the APS is there any way of testing this to see if it is
functioning correctly as I don`t fancy buying a part which is not required.

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.

I assume case is sealed as ignition occurs but then goes out after a period
of time, surely if the case was not sealed it would not go on for so long a
period can be up to 30 minutes.


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.

Have cleaned all relevant parts.

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.
My thoughts are moving towards the APS as I said is there a method of
testing this or do I just replace the part?