Vaillant vcw 242 e no CH

[mouse2674]

Can some give me a little advice I have above boiler that is not giving me Ch when requested off controller But have 240v on pin 4 on PCB but fan does not come on.However if DHW is on and the request for CH is on the CH will come on OK Also when DHW is requested the system pressure on front gauge wavers a little as it fires up.Both Diverter valve and water valve where changed 9 months ago do these need adjusting,or could it be the restrictor on the banjo connector on diverter blocked so restricting the diverter valve position at home (so this is why system pressure moves a little??)Please help ?

 

[bengasman]

Could be sensor problem, pcb problem, or stuck diverter. Are you sure the system is clean?

 

[mouse2674]

Thanks for speedy reply had servo control valve off today and all control lines into it off and cleaned not much black s##t came out.Also found that if switch boiler off on red green switches then back on the CH would kick off if had 240v on pin 4 otherwise it would sit there doing nothing!

 

[mouse2674]

Was thinking of taking Diverter off tomorrow to clean ? Is this wise or is it complicated?

 

[mouse2674]

also put sunvic controller on as old Potterton ep 4000 lcd screen was broken could this make a prob?

 

[bengasman]

I doubt the sunvic would cause this problem, but it is a really crappy controller.
Taking the diverter apart is not hugely complicated, if you have experience with mechanical engineering in some form or the other. Do it wrong, and you make the problem worse.

 

[mouse2674]

I'll give it a go .How does the CH system work (basic) I can see how the DHW signal via water valve (nodding donkey) cam .But can't see where signal from the PCB gets to diverter valve to make micro switches ?Thanks for your help

 

[bengasman]

Is this the one that is also known as the minicombi? If you can see a load of small pipes connecting one bit to the other, they are prone to clogging up.
If it is the one I am thinking about, the mechanical parts can be adjusted to achieve the correct play. Moving parts can be sticky, microswitch can be wonky, or the diaphragm can be duff.

 

[mouse2674]

Does the servo control valve effect the CH system or just DHW ?

 

[mouse2674]

It is the one which can be adjusted mechanically The water valve pin can be adjusted that operates the servo control valve and also at the end of the Diverter vale the microswitch plungers are adjustable Although the movement on this looks nice and smooth!I checked water valve diaphragm yesterday this was fine and the pin moves up ok and hits servo control valve cam.I dont think it is the mini combi Its a VCW GB 242 E B

 

[bengasman]

Next step would be to check microswitch.

 

[mouse2674]

One of the two at the end of the diverter valve ?Sunvic only one left on the shelf at wholesalers!!!

 

[mouse2674]

In work have to go and do a bit thanks for your help you have give me something to go on for tomorrow this boiler won't beat me!!!!!!!!

 

[bengasman]

These boilers are tanks, bit of tlc and you may get another decade out of them.

 

[Ihavenojob]

Sounds like the anti cycling device is playing up,can be adjusted behind screw to the right of switches on control box +/- with arrow,but may need new pcb,cant remember which one.