VAILLANT VCW GB242 EH hot water ok, heating dodgy....fixed?

i wanted to thank all the corgi people and competent diyers who posted responses to similar problems to mine.

sifting thru them pointed me to a solution which i hope may help anyone experiencing the same with their VAILLANT VCW GB242 EH

after checking the function of the servo and the diverter.... the servo cam was turning and activating the microswitch... the diverter was correctly moving between the heating and hot water positions.....

edit: please be aware this may only be a temporary solution and as is mentioned further in the thread the underlying problem is probably something like the servo valve

the solution
i noticed that one of the microswitches on the diverter wasn't being triggered properly... i made a slight adjustment of about 1mm and hey presto!

step by step if it helps
to get to the diverter, i took off the cover on the right side of the boiler. at the bottom is a semi transparent plastic cover thru which u can see 2 microswitches and the diverter

when i took off the cover i could see the diverter properly and watch it moving as i selected either hot water or heating... at this point i noticed the metal prong at the top (for want of a better word) was only just making contact with the top microswitch... presumably any vibration was letting the switch pop out again... there are 2 bolts to allow adjustment of the prong

thanks again for everyone who contributes to the forum, you saved me from a freezing cold christmas

How did you conclude the microswitch was out of adjustment?

Why not the diverter valve malfunction, servovalve travel incorrect, pump lazy, tubes partially blocked to name a few.

as the hot water worked perfectly and the heating worked but intermittently i ruled out the pump and the fan (i checked the pump tho)

i did suspect one of the control lines on the servo to be blocked at first as it has a very sharp bend in it which looks like it could easily get blocked... but i didnt fancy taking it apart

when i watched the diverter pushing in and out correctly (i assumed the servo must be working properly) and engaging the microswitches i disconnected them one at a time to see what did what

once i worked out which was the ch i then watched to see it was actually switching each time... it wasn't, i then just adjusted it in 1mm or so and it worked

i'm not advocating people adjust it loads if the diverter isn't moving properly... that would need to be sorted out properly

i think it is just due to vibration over the last 15 years that it needed slight readjustment

You will find you have to adjust it again in next month or so. There is minimal to no vibration on 242`s . YoUR actual fault is the servo valve worn and not delivering correct pressure to move divertor spindle fully.

cheers namsag

i'll come back and post again if/when that happens

i'm by no means saying i've found a miracle cure for everyone, perhaps just a temporary fix... and even then i wouldn't have been able to do that without all the expert advice i've found on the forum

the point namsag is making wiggy is

your treating the symptom not the disease

no i do appreciate that kev i've now edited my original post to reflect that.... when the problem reoccurs i'll change the servo as advised

sorry, i thought it would be useful for some people to get their heating running again even if temporarily... i should have worded my thread better

i think in my own case i thought was caused by vibration as the there was some movement in the parts that can be adjusted... and the boiler does vibrate when my washing machine goes into spin but obviously you guys are the experts and this is how we learn, many thanks for all your input

i shouldn't jinx it... but it's still working ok 10 weeks on

wiggystardust said:

i shouldn't jinx it... but it's still working ok 10 weeks on

Click to expand...

nearly 3 years on still working!!