Vaillant VCW GB 242 EH - No Hot Water

[garethr83]

Original problem 2mths ago was that the ch would heat up then cut out after 10-20secs whilst HW was fine.

A new diaphragm and £130 for the 'privilege' and all was sorted.

The reverse has now happened 2mths later with the hot water heating up then knocking back off after 10-15secs yet the CH is fine.

I have done several searches but cannot find a solution.

Firstly does anyone have a service manual I can have?

Secondly I understand it could be any of the following:

Blocked pipework, sticky needle, incorrect adjustment etc.

What should I check first? I would like to remove the diverter valve and give it a good clean but not sure how it is attached to the microswitch? I can see 4 nuts that simply undo but I need to know how to turn the water off first. Must I bleed the boiler etc?

Advice appreciated as I don't want to pay another £130 for probably the same thing and I cannot justify £700 on a new boiler

 

[kevplumb]

Firstly does anyone have a service manual I can have?

yes

 

[garethr83]

so can I have it please? lol

 

[kevplumb]

help yourself it's on my "j" drive under vaillant

 

[garethr83]

removed

 

[glasgowgas]

stick email in yer profile

your bank account will probably be empty now!!

 

[kevplumb]

sent

 

[garethr83]

many thanks

any ideas on teh second part now then lol?

 

[garethr83]

oddly heating has now come back on

however there appears to quite a substantial leak coming from the 'differential valve????'

does that mean that it is possibly the diaphragm that is shot?

I'm guessing the above part is the 'differential valve' from what I can make out from the manual (diagram is darkened)

Would that have caused the symptoms?

 

[kevplumb]

 

[garethr83]

what does that mean?

I need to know if that is indeed the 'differential valve'

because before I remove it to solve the leak I would like to know what parts I would need....

151017 for the said valve? Would this include the diaphragm etc.
http://www.mjtcontrols.co.uk/Appliance_Type3.aspx?Manufacture_ID=52&Appliance_Type=GAS+BOILER
?

 

[kevplumb]

means i boobed and deleted the post

 

[garethr83]

so would the leaking valve been an indication of a blockage and would this have been the root of my problem?

is teh part number I list correct as there is a part number on the housing itself of 207908 R

 

[DP]

Sent a reply to your Hotmail accound but you have not answered

Wrote "Is the diverter (under the pump) moving to the right for hot water and left for CH (look at the microswitches under the plastic cover)?

Leave the water section alone. If when boiler is not supplying heating, running a hot tap starts the boiler, then water section is fine."

What is the answer?

Dan

 

[garethr83]

yes both of those are working fine

so would this pressure valve have been a likely cause and do I have the right part number?