Vaillant VCW GB 242 - No ignition now fixed! Now leaking???

[garethr83]

I have an old Vaillant VCW GB 242

I developed no hot water unless I activated the servo switch manually, as a result I took it apart and have now fitted a new diaphragm as the old one was shot and also a new servo valve.

Fine I thought, put it back together but the thing would not ignite.

Been reading all over the net and have found two things that have been of help:

He phoned Vaillant again and they then said take off a tube at the back going into the combustion chamber and blow down it, softly first then hard, if flame profile increases when blown hard it’s definitely the ‘gas section operator servo’ on the main gas valve.

I did this and the thing fired up with ridiculously high flames. In the manual it also suggests fitting a tube to the test point (to the left of the tube mentioned above) and sucking. The same thing happens.

So I guess that the problem is indeed the 'air pressure switch'.

Any ideas on part numbers or anything else to look at before I order the part and get one of the guys in work to fit it?[/quote]

 

[Agile]

We dont give advice on gas or safety aspects on this forum.

If your guys at work are qualified to work on boilers then let them diagnose the fault and correct it as required.

Tony

 

[garethr83]

Any ideas on part numbers or anything else to look at?

 

[Deansat]

'air pressure switch' In the manual it's 050518
All the best Dean.

 

[garethr83]

would both of the tests I did indicate this or could it be something else?

I never touched the gas section so not sure why this has happened since I only plumbed in the water section after removal?

How long would it take to fit the pressure switch? My plumber mate charges £20 an hour

 

[Deansat]

I’m not a plumber or anything like that and I did it in less than ten minutes. It’s only one screw two plastic pipes and a couple of wires to push on after you have taken the side and front off the boiler I got a new one off eBay for about £9
All the best Dean.

 

[garethr83]

If by blowing through the pipe that is connected to the flue collar gets it to work or sucking on the 'test point' gets it to work then surely the switch is working?

Something must be preventing the tube from being 'blown through'? Would this be down to the fan or something?

Thanks

 

[garethr83]

all fixed!

never fitted the front cover lol, no wonder there was no pressure for the switch to work! doh

I also have a big leak from the black plastic box/unit lower left hand side with 4 pipes going to it. Secondary heat exchanger. Although the part number I have in the pdf manual is 064947.

When googling, this part number is a metal box and has the 4 outlets on the front of the unit whereas the existing has on eoutlet on the top, two on the side and one on the front.

Any thoughts?

 

[Bunnyman]

Jesus u didn't fit the front ffs! Stay awAy from gas

Untitled

• Bunnyman
• 26 Mar 2010
• 499

 

[petit_pablo]

Jesus u didn't fit the front ffs! Stay awAy from gas

Untitled

• Bunnyman
• 26 Mar 2010
• 499

Scary isnt it! At least he is in wales, way to far from me to cause me trouble