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Posted to uk.d-i-y
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Potterton Netaheat Electronic won't fire up?
In article ,
says...
Hi all,
A while ago some might remember me mentioning here that an elderly
neighbour we keep an eye on was finding heating on when she only
wanted hot water. I believe the diagnosis was the rubber ball in the
motorised valve was allowing water past into the CH cct when in the HW
position and I bought a new valve ready.
She was happy to just use immersion for HW so I thought we'd wait till
it was a little bit cooler in the loft and in general before doing the
job.
She mentioned to the Mrs earlier that it was starting to get a bit
cooler and so I just popped over to swap her back to the gas boiler
and re-set the timer to get things flowing again and whilst it looks
and sounds like it's trying to spark up, it's not managing to?
We have the water pump running (checked via the spindle cover), the
boiler fan, the igniter bit it looks like it might fire up a pilot
flame failure detector main burner but isn't getting the pilot, if
that's actually what happens. If it should light the main burner
directly from the igniter it's not doing that either. [1]
I can't smell any gas on the outside but I can feel reasonable
airflow.
Turn the main boiler knob to off, leave it a few seconds, turn it back
on again, and you hear the fan come on, then after a few seconds
delay, a fairly loud 'clunk' (gas valve?) and then the igniter starts
going but that's it? She has gas on the hob nearby.
Anyone had / got one and can remember the fire up sequence or can
offer any other thoughts please?
I've swapped her back to the immersion heater for tonight and can have
a closer look in the morning.
Cheers, T i m
[1] If you peer into the boiler though the spy hole and watch
carefully, every 3 or 4 sparks it looks like it is surrounded by a
tiny flame but as if it's blown out before it can build up?
Mine has exhibited these symptoms. Here's what I do to mine.
Isolate from electricity.
Pull off the thermostat knob. Remove a 'rubber' bung to reveal a screw
which holds on the control gear front cover. Remove the screw (mine is
captive)and the cover.
There is a clear plastic tube which passes through the steel backplate
close to the spark generator black box. It goes into a pressure switch
(a disk about 75mm dia). Where it passes through the backplate, the
plastic tube is jointed by what looks like a bit of brass tubing. But
this is a restrictor, with a very tiny hole in it. Pull the clear
plastic tubes off it and blow it out, or carefully probe with a fine
needle. Job done, I do it routinely about every 5 years.
You can test if the boiler starts by turning on the electricity, there
will be live terminals exposed, and sucking on the tube that goes to the
pressure switch. Re-assemble.
Hope this fixes it.
--
Take the dog out to email me
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