Vaillant combi

[Brutal]

Right I've got a Vaillant combi boiler serial VCW-GB 242EH/WCW-GB 282EH. I've been in the house 3 years now and not a problem until last week. We have B.G homecare the the last annual service was done in November. Engineer said all was ok etc. The boiler itself is over 10 years old but have been told its worth keeping. The problem is the HW is working fine but the CH is itermittent. It started last Thursday. CH would come on and after 10 minutes or so it would go cold tho the system was still on. I spoke to a m8 and he suggested a few things. All the rads were cold. So i bled them but there was hardly any air in the system. I turned off the system completely and turned it back on. The CH worked again for 30 mins and went cold again. Turned it off again and it worked fine for the rest of the night. But on Thursday it went again. So called out B.G and the guy was not happy bunny, said out boiler was old and that we should replace it. But anyway he (claimed) fixed it, said it was a airblock in the boiler itself. But today its packed in again. HW fine, no CH. But after having a good look myself when the HW is turned on the boiler lights straight away but when i turned on the CH nothing. I here a click but no ignition. So we are now waiting on B.G to turn up today to fix it again.

Any ideas on the problem????

 

[ChrisR]

Have a butchers here:
//www.diynot.com/forums/viewtopic.php?t=67059

 

[ltheb]

You say you bled the rads, did you re-pressurise the system?

 

[ltheb]

Sorry, just re-read your post, I can't believe the engineer would not have repressurised the system.

 

[Brutal]

Sorry, just re-read your post, I can't believe the engineer would not have repressurised the system.

Well when i bled the rads i did recheck the pressure. I guess by your term repressurising the system you mean topping up the water???

As for the link ChrisR i didn't see that one when i searched but thats far too advanced for me to try and sort out for myself. Computers yes, boilers no...lol.

I'll await a call from MR B GAS! Do you think its time for a new boiler? If it was then i guess the engineer that did the annual service was talking bull cos he said there would be no problem getting parts etc.

 

[weareleeds]

I would be looking at changing diaphragm in divertervalve along with the switches also checking servo valve & tubes for blockages Has plate heat ex being renewed as plastic ones leak quite a lot

 

[ChrisR]

I expect there will be plenty of those around in 10 years time. No problem with parts. Built like the proverbial.
If you get to know how it works you could save yourself getting a new boiler before you need. A lot of boiler blokes will tell you it's too old.

A new boiler would be more efficient, but the payback would be a long time. If you need to move it, or have more performance in terms of hot water, it shifts the equation.

 

[Agile]

I now wonder if BG really came this afternoon?

 

[wiggystardust]

i have the same boiler and had the same fault until about 2 days ago..

i discovered that the microswitch on the diverter wasnt being triggered correctly.... i already posted it here //www.diynot.com/forums/viewtopic.php?t=73165

fingies crossed!

 

[Brutal]

I now wonder if BG really came this afternoon?

Well guess what BG didn't turn up. Really ****ed off with them. But anyway i managed to get it going again but i cant understand it..lol.

I bled the rads again when the CH wouldn't heat up and suprise it worked. As soon as i did it i could feel the water warming up. Happend again this morning after coming on at the normal time but went cold after say 2 hours. But this time i turned the system completely off, turned it back on and hey presto it worked.

I expect my misses will tell BG to go and jump off a cliff when she next phones them. We've already been fobbed off by BG by offering us a months free gas if we came back, pity they didn't tell us we had to be with them 3 months b4 we could get it.

 

[Brutal]

Well after waiting for BG i gave up and decided to look at the boiler myself. Looked at Wiggystardust's post and did what he did and guess what it appears to have fixed the problem. Boiler lights up fine when the CH kicks in. So hopefully that will be the end of it! Just annoyed that BG engineer didn't think of that.

Anybody using Npower's boiler service???

 

[DP]

Maladjustment only gives temperory relief.

How do you know lack of travel is not due to some other problem?

Not the first time I have seen a thermocouple bent over to reach smaller pilot flame instead of looking at the cause and effecting repair.

 

[wiggystardust]

hi, i'm glad it seems to have helped

mine wasn't always adjusted wrongly i think it had just worn loose over time as the boiler is about 15 years old and looks like it's never had anything done before, i just used a tiny bit of built in adjustment and the diverter is moving freely

having being quoted £450 to have the fan replaced which i was assured was the cause of the fault i decided to have a look myself and that's what i discovered

i fully appreciate what u are saying... fix the cause not the symptoms... in my own case i'm sure the cause was general wear/tear and vibration just meant it need to be re-adjusted as the diverter is actually moving freely and properly

 

[wiggystardust]

dp, namsag and kevplumb... thank you for your input and advice and when i do change the servo i'll definitely be wanting more advice

 

[Brutal]

Maladjustment only gives temperory relief.

How do you know lack of travel is not due to some other problem?

Not the first time I have seen a thermocouple bent over to reach smaller pilot flame instead of looking at the cause and effecting repair.

Well since I did do a very slight adjustment all has been fine. To be honest it is even mentioned about doing this in the Vaillant manual (under servicing) so if they say that then they must allow for wear and tear. I know one day the boiler will die due to its age but till it blows up or completely gives up the ghost why change it?