Vaillant TurboMax - No Hot Water but Central Heating OK...

[Milton]

My Vaillant TurboMax boiler has stopped supplying hot water to the taps but Central Heating is fine (hot water tap light rarely comes on when running hot tap - will for a bit sometimes then stops and water go's cold again). Now from reading around the forum people are saying it's either the Diverter Valve, Microswitch, Diaphram or plastic needle that hits the microswitch. Not knowing anything about boilers (I'm a Network engineer by trade) I was hoping someone could give me some pointers as to how I can isolate this problem so I can have an idea of cost to repair before calling an Engineer out.

Any ideas greatly appreciated...

Cheers,


P.S. I was up in the attic when it stopped working laying some rockwool and it's in my head that I could have done something to affect this ? Not possible right ?????

 

[markymark1234567]

It will be the diverter valve. If you take the front off the boiler then unscrew the 1 screw in the middle so the main front falls down. Look at the large brass section behind the pump you will see a small black plastic microswitch. Get someone to open a hot tap and you look at the boiler it should move down if not it's the diverter valve.

 

[ianniann]

Doesn't this boiler have what you might call two diverter valves? Other Vaillants I'm familiar with have what they call a water section which senses the water flow and turns on the boiler, and a separate valve that actually diverts the flow through the heat exchanger.

In this case the symptoms suggest that the water section is not operating, or only operating perhaps if you get a very high flow rate. They are adjustable and also sometimes may just need cleaning, but usually when they start playing up they need to be replaced.

 

[Milton]

It will be the diverter valve. If you take the front off the boiler then unscrew the 1 screw in the middle so the main front falls down. Look at the large brass section behind the pump you will see a small black plastic microswitch. Get someone to open a hot tap and you look at the boiler it should move down if not it's the diverter valve.

OK- will give this a go.... If it is moving down then is it the microswitch at fault ?

 

[Agile]

I thought that all ( or most ? ) of the Turbomaxes had a turbine DHW sensor?

Tony

 

[Milton]

okay so I'm getting there with this...I think

I checked out the diverter valve while running a tap and noticed that the White arm/needle wasn't pushing the microsensor arm down enough to make contact - I've adjusted this with a bit of card to test a theory and Voila it's now working.... Now for a long time fix.... Would it still need an engineer to replace the whole valve or this a cheaper job now ?

Many Thanks for your help so far guys.....

 

[Gasguru]

Providing the white arm isn't broken and there are no visible water leaks around that area you can just get a diaphragm kit. Not a particular easy diy job though. If it's still on its first diverter I'd get the whole valve changed. Don't forget to check the vessel pressure and replace the auto air vent.

 

[Milton]

Providing the white arm isn't broken and there are no visible water leaks around that area you can just get a diaphragm kit. Not a particular easy diy job though. If it's still on its first diverter I'd get the whole valve changed. Don't forget to check the vessel pressure and replace the auto air vent.

Yeah..cheers..Don't think i'll be attempting anything further on this though...I've gone as far as I can...probably a bit too far...

Anyway, I believe it's still on it's first diverter.

So my options are :

1) Britsh Gas Fixed price Fix £168 (no guarantees they'll change the whole valve though I suppose ?????)

2) Private Engineer to fit diaphragm kit - Any ideas on a ball park going rate figure for this job ?

 

[45yearsagasman]

The fix on this is quite simple.Diaphragm change should suffice.Diverters are pretty reliable.You just need a degree in Meccano and be methodical.

 

[Milton]

The fix on this is quite simple.Diaphragm change should suffice.Diverters are pretty reliable.You just need a degree in Meccano and be methodical.

Don't tempt me...Thing is I wouldn't know where to start to even drain the thing let alone get to the diverter valve and then take it apart (assume i'd have to take the pump off first?) and fit the diaphragm....

Thanks for the advice though and it is tempting me to just give it a go...Famous last words.

Any idea on a part code for this diaphragm kit so I can get an idea on price ?

Don't suppose theres any fitting instructions around as well ?

 

[olly_k]

I think about £15 from plumb centre about 3 years ago. That was for the upper and lower diaphram kits!

 

[Bunnyman]

010365 diaphram kit bit awkward to fit I usually leave valve in prob best to call an engineer

Untitled

• Bunnyman
• 26 Mar 2010
• 499

 

[Milton]

010365 diaphram kit bit awkward to fit I usually leave valve in prob best to call an engineer

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• Bunnyman
• 26 Mar 2010
• 499

Great thanks - part seems cheap as chips really... what about engineer labour would I say be looking to pay no more than ££££(?) for this sort of job ?

 

[Bunnyman]

We supply an fit £105+vat

 

[Agile]

On a 242 style diverter valve model we always fit a complete new valve as that eliminates any callbacks as a result of other valve failures.

Tony