Hot Water but no central heating on Vokera Combi boiler

[George01]

My boiler is a vokera compact he combi, and it has stopped giving me any heating but i still have hot water. There are no warning indicators on and the pressure is ok.

The boiler fires up ok, when calling for heat, for about 5 seconds and then stops. I have spoken to technical help at vokera and they say it could be a blockage in the system.

I can hear a clicking sound coming from the diverter valve motor which i don't think was there before. I have taken this part off and checked it but not sure what i am looking for or whether i am looking at the real problem. Should the internal cogs turn freely?
Any help appreciated.

 

[glasgowgas]

when you run the combi on central heating does the 2nd pipe in from the left( underneath the boiler, 22mm pipe get warm,hot,f**k me hot or what

how old is the combi?
anything changed recently?

 

[George01]

Nothing changed recently with system. Was working fine 2 days ago.

The pipe you mentioned does not get hot, stone cold infact.

The boiler is approx 3 years old.

 

[glasgowgas]

is your pump running ok, your manufacturers instructions will tell you how.

or the diverter valve is defective, but one thing at a time.

check if pump running first

 

[George01]

The pump seems to be running because the hot water still comes on. When the boiler is trying to activate the heating the pump does seem very hot but this is normal?

 

[glasgowgas]

the pump will get warm but not superheated.

sounds very much like diverter valve is not motoring to open for central htg( actually a back up system, if motor fails you still have hot water)[/quote]

 

[George01]

Thanks for the help glasgowgas always good to ask someone in the know.

Think i will order a new diverter valve motor, looks like they are fairly easy to fit and cost about £40-50.

Is there any way to change the position of the valve manually to make sure the system is ok? cant find any slide or knob to push.

 

[glasgowgas]

u have have already stated that u have had the divertor motor off, take it off again, place it so you can see the spindle and run central htg. does spindle turn, if so cartridge inside is knackered ( could be crud in system gunged it up ) if not turning divertor motor knackered. if not turning my next step would be to check their is power at divertor motor.

best of luck brother

 

[George01]

Update:

Have checked that i have 230V at motor. Ok.

Have taken the motorized valve off again but was unable to see if the spindle turns whilst system calling for heat.

Decided to strip out the 3 way valve cartridge, and discovered quite a bit of sludge and solid build up inside (did not get the cam out because it was stiff and i didn't want to break it). I cleaned it all up and put back together and restarted the system.

I now have central heating and only lukewarm water . Does this sound like the 3 way valve cartridge needs replacing or could it still be the motorized diverter valve?

 

[glasgowgas]

ideally, you would want to disprove something before moving to next logical step.
there is power at div. head but is it turning?
power at div head but no movement, faulty div head
power at div head and movement, faulty cartridge

best of luck

 

[George01]

Have checked div motor whilst system running,(thought was going to get drenched!) and it is working ok. So, like you say, it could be the cartridge.

It looks like the price is the same for this part as the motor. Will order one and give it a go. Are they fairly easy to install? The inner cam seems like it might take some getting out.

Thanks again for your help, any advise you need on electrics i will return the favour.

 

[glasgowgas]

the vokera insallation manual is pretty much step by step.
read it, then do it!!!!
or an old anacronym i was told K.I.S.S.
Keep
It
Simple
Stupid
!!!!!!
best of luck brother