Hi, got a Vaillant 242e and its not igniting for either hot water or heating. It makes all the right clicking sounds, pump starts and flue fan starts (only when running hot water tho?).

I've replaced the Flame Ignition PCB and Fan Module PCB tonight, and the mainboard was replaced 2 years ago. However its still not igniting.
My brother in law is a plumber and we've gone thru the fault diagnosis in the Vaillant manual, all of which lead to it being one of the PCB's.

Could it be the Thermostat PCB that is at fault or might it be something else?

Also worth mentioning, I can't see a pilot light in it, however the reset switch hasnt popped out??

Full Model No. :- VCW GB 242E

On Thu, 16 Dec 2004 19:12:49 +0000, rdean wrote:


Hi, got a Vaillant 242e and its not igniting for either hot water or
heating. It makes all the right clicking sounds, pump starts and flue
fan starts (only when running hot water tho?).

I've replaced the Flame Ignition PCB and Fan Module PCB tonight, and
the mainboard was replaced 2 years ago. However its still not igniting.

My brother in law is a plumber and we've gone thru the fault diagnosis
in the Vaillant manual, all of which lead to it being one of the
PCB's.

Could it be the Thermostat PCB that is at fault or might it be
something else?



Full Model No. :- VCW GB 242E

The fact that the flue does not start for the CH does seem wrong.
For the water heating is the sparker clicking?

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Ed,
Yes it does seems strange doesnt it, as for the water heating , there are a few clicks, it sounds as if its getting all the way there, but no ignition.

Is it strange that I can't see the pilot light too

On Thu, 16 Dec 2004 23:22:12 +0000, rdean wrote:


Ed Sirett Wrote:


The fact that the flue does not start for the CH does seem wrong.
For the water heating is the sparker clicking?

--


Ed,
Yes it does seems strange doesnt it, as for the water heating ,
there are a few clicks, it sounds as if its getting all the way there,
but no ignition.

Is it strange that I can't see the pilot light too

There are no pilot lights on the 'E' model for electronic ignition.
Some boilers with electronic ignition do have two stage ignition using a
temporary pilot light - but this model is not one of them.

Leaving aside the CH problem there is a weird fault on this model which
looks like a PCB failure but is in fact just a water flow sensor problem.

When the water flows it move a small piston which operates a small valve
(sort of triangular with 4x 4mm pipes on it)
and a microswitch. The latter starts the pump which on account of the
former causes the diverter valve to shift to HW. More switches are closed
this starts the ignition sequence.
It turns out that if the microswitch does not maintain contact the
ignition sequence is put on hold at the gas valve stage.

So the boiler appears to have a broken gas valve.

The cure is to overhaul the water flow diapragm - easy enough
but there are a lot of little pipes and quite a few big ones too,
and the boiler has to be drained. The book states how to do it.

You can test that this is the case by operating a tap and manually
encouraging the microswitch (taking care over its 230V contacts).

This seems to be a stock fault on 242s after about 10 years.

Maybe the piston is not retracting properly and thus the CH won't go
either?

HTH

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Hi Sorry to jump on this, especially so long after it was originally posted, but it sounds a bit similar to the problem I'm having and wondered if the cause be the same.

I have a 242e or a 282e (according to the manual, can't find the model on the unit).

When the heating is turned on, the pump runs, but the burner never fires. If, whilst the heating is on (pump running), I turn a hot water tap on, the burner will fire, and the radiators will start to heat up.

However, as soon as the HW is turned off the burner shuts off, and the radiators go cold again.

Initially it only did this intermittently, but turning it back on after summer, it now does this all the time.

Any thoughts greatly appreciated!

Thanks,

Ben.

On Wed, 16 Nov 2005 14:43:45 +0000, Edev wrote:


Ed Sirett Wrote:
On Thu, 16 Dec 2004 23:22:12 +0000, rdean wrote:

You can test that this is the case by operating a tap and manually
encouraging the microswitch (taking care over its 230V contacts).

This seems to be a stock fault on 242s after about 10 years.

Maybe the piston is not retracting properly and thus the CH won't go
either?



Hi Sorry to jump on this, especially so long after it was originally
posted, but it sounds a bit similar to the problem I'm having and
wondered if the cause be the same.

I have a 242e or a 282e (according to the manual, can't find the model
on the unit).

This is either a VCW 242 E which has a pair of switches and a black knob
marked 1-9. Or it's a 'Turbomax' VUW 242e/282e This has a column of leds
with various 'euroglyphics' next to each one, The control panel is
black(?) plastic with turquoise(?) knobs.

When the heating is turned on, the pump runs, but the burner never
fires. If, whilst the heating is on (pump running), I turn a hot water
tap on, the burner will fire, and the radiators will start to heat up.


However, as soon as the HW is turned off the burner shuts off, and the
radiators go cold again.

Initially it only did this intermittently, but turning it back on after
summer, it now does this all the time.

Any thoughts greatly appreciated!


This would be the symptoms of a VCW 242 with a diverter valve that can't
quite make it to the CH position and so begin the ignition sequence.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Sorry - it's the VCW.

Many thanks.

Ben.

On Thu, 17 Nov 2005 10:29:10 +0000, Edev wrote:



I have a 242e or a 282e (according to the manual, can't find the
model
on the unit).

This is either a VCW 242 E which has a pair of switches and a black
knob
marked 1-9. Or it's a 'Turbomax' VUW 242e/282e This has a column of
leds
with various 'euroglyphics' next to each one, The control panel is
black(?) plastic with turquoise(?) knobs.

Sorry - it's the VCW.


This would be the symptoms of a VCW 242 with a diverter valve that
can't
quite make it to the CH position and so begin the ignition sequence.

Many thanks.
[/color]
The valves are not too bad at around £60 or so. The work involved is
complex and should not be tackled unless you have the manual to hand even
if you have done a few before.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html