New Vokera Boiler is constantly heating and wont stop

[amrd02]

Hello All

I have a 3 year old Vokera Mynute HE35 boiler, whos warranty has just run out. It is controlled via an external Digital Programmer.

It was working fine last week but now, I can't stop it from constantly heating up the hot water. The radiators dont seem to be affected. The digital programmer doesnt seem to be able to switch off the boiler anymore, and the only way I can do it is by turning it off on the wall, which obviously means I have no hot water. The boiler display shows no fault lights or errors, just a green 'heating' light.

Ive read up some previous threads, and have found that faulty connections or the Microswitch is usually the problem, But I have looked at the programmer wiring and it doesnt seem to be loose and Ive also looked in the manual for diagrams of my HE35 and I dont think it actually has a microswitch!

Does anyone know what the equivalent of a microswitch could be in my boiler or what could be causing the problem?

Aaron

 

[Agile]

Is this a heat only boiler with a motor valve with a jammed microswitch?

I dont consider a three year old boiler "new".

What does the installer have to say?

Tony

 

[amrd02]

Thanks for your reply.

All I know is that's its incorporates electronic ignition, circ pump, expansion vessel, safety valve, pressure gauge and a flue system. When there is a request for hot water from the programmer, the pump and fan start, and the pcb ignites a burner which heats water.

The manual is of no use and I haven't asked anyone professional about it yet, although if I can't fix it myself I will probably take out insurance cover for it, although I won't be able to claim for 2-4 weeks from taking out cover.

Any ideas?

Aaron

 

[flameport]

Ive read up some previous threads, and have found that faulty connections or the Microswitch is usually the problem, But I have looked at the programmer wiring and it doesnt seem to be loose and Ive also looked in the manual for diagrams of my HE35 and I dont think it actually has a microswitch!

The microswitch is located in the hot water zone valve.
It is not part of the boiler or programmer.

 

[45yearsagasman]

Look for something like this View media item 30391

 

[amrd02]

Thanks.

Interestingly, a few hours later, the boiler started working normally again. But now, it wont heat up at all, and doesnt seem to be responding at all to the programmer. Again, no error code visible.

Has the thermostat gone?

 

[Agile]

Which thermostat?

Is one missing?

 

[amrd02]

Just to update

I gave up trying to fix it myselgf, because of a lack of time and having to go to work, so called a plumber.

Up in the attic, he replaced the zone/divertor valve, as 45yearsagasman had shown a picture of.

I paid £157 for the privilege of having it replaced (although I took the plumbers word for it that it was the whole valve and not just the microswitch inside it that was a problem - The whole valve cost £70, the microswitch around £4 so I have my doubts!).

Next time, Ill know what to do at least.

 

[mfarrow]

Generally, it's the valve sticking rather than the microswitches, so your plumber has done good.

 

[Agile]

No plumber would ever replace the microswitch although DIYers sometimes do.

Its normal to replace the head assembly as thats quick.

The shaft can become tight and is best replaced although they can often be freed up with WD40 ( for a while! ).

The whole body is usually replaced although the shaft and ball can be replaced on their own. I dont know why but few people actually do that! The system still has to be drained which is most of the work!

Tony

 

[DP]

Tony, are you saying the ball itself or the saft alone can be replaced?

WD40 is not a lubricant, so I would not use this to lubricate the shaft. WD40 stands for Water Displacement compound 40

My preference is silicon spray

 

[picasso]

Replacement ball and shaft

http://www.heatingcontrolsonline.co.uk/honeywell-40003918006-conversion-kit-p-288.html

also used to update old zone valves.