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Plumberpro
Plumberpro, Home Appliance Technician
Category: Appliance
Satisfied Customers: 634
Experience:  Heating and hot water heating appliances experienced
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Vaillant Combi Compact VCW GB 240H Originally hot water stopped

Customer Question

Vaillant Combi Compact VCW GB 240H
Originally hot water stopped working, gas would fire up for water but did not heat the water. advised that 'Diverter valve' was more likely the problem. Bought and changed diverter valve. No success, diverter valve is humming, sounds OK, gas does not fire up for hot water. Please tell me the fault? thank you
Submitted: 2 years ago.
Category: Appliance
Expert:  Plumberpro replied 2 years ago.
Customer:

Hi ,sounds like the hot water flow switch is faulty

JACUSTOMER-oh4mwymr- :

Toby, Do you have a part number. cheers peter

Customer:

Ok , sure give me a couple of mins , thanks

JACUSTOMER-oh4mwymr- :

Will the hot water flow switch also turn on the gas burner?

Customer:

Hi . not sure about that last now . this is the old hydraulic valiant system , there is no flow switch .just going to download manual

Customer:

Need to check with valiant

Customer:

Hi , sorry for the delay . there is a hot water micro switch ( m1) that should fire the boiler on hot water demand . this is under the grey servo unit . open the hot tap and check the switch is making . you can also try to operate it manually with a screw driver . this should make the boiler fire

JACUSTOMER-oh4mwymr- :

Could you please send me a print of the grey servo unit & micro switch? cheers peter

JACUSTOMER-oh4mwymr- :

*****@******.***

Customer:

Emails won't come up . they are blocked by the site unfortunately.

JACUSTOMER-oh4mwymr- :

Is the micro switch at side of 'diverter valve'?

Customer:

Vaillant - CombiCompact VCW GB 240 - Lets Fix It.

Customer:

This will allow you to download the manual. Just getting the part number of the micro switch

Customer:

The diverter is separate from the servo section . the water is diverted through the servo unit . this operates the hot water micro switch. If the pump is failing and too weak then the flow won't be strong enough to operate the switch . so it could be either the hot water micro switch. Which can be checked by manually operating it( boiler should fire ) or could be the servo unit. The other possibility is the pump needs replacing. You can check the pump by opening the bleed screw and pushing a screwdriver in and seeing if you can stop the pump spinning . if you can replace the pump.

Customer:

Sorry , have to pop out for an hour

Customer:

Hi . was that info ok?

Customer:

Hi . the micro switches are under plastic covers unless they have been lost

Customer:

Full Size Image

Customer:

Hi . how did you get on ? Was that info ok for you? If so would you mind rating me , thanks

Plumberpro and other Appliance Specialists are ready to help you
Customer: replied 2 years ago.

I am in the process of calling in boiler engineer for direct advice,

cheers

Expert:  Plumberpro replied 2 years ago.
These boilers are amongst the most difficult. When I was with British gas onlyba few engineers could work on them .