Vokera Boiler turning on and off

[rallyingden]

Hi I have a Vokera compact 28 boiler. It has developed a fult when heat is being called for the boiler ignites OK but after a few seconds .... longer sometimes it turns off again, NOT LOCKOUT. then fires up again runs, stops and this continues while heat is being called for. The fault happens on both CH & DHW demand.............


Any Ideas ??

RD

 

[Agile]

Nothing obvious comes to mind at the moment as most problems which affect both CH and DHW will cause a lockout.

In front of the boiler I would be measuring temperatures and timing the on/off cycles and seeing if there was any correlation with each other.

Tony

 

[rallyingden]

Cheers Tony

I too wondered what could be common to both.......

Secondary ( DHW ) thermistor .............. Tried a new one

PCB.............. Tried a new one.

Got me baffled this one

 

[Sloop]

How about ignition board or spark electrode, just a thought?

 

[Agile]

The DHW thermistor has no effect on CH.

The CH thermistor gives a red light if it goes open circuit.

The ignition electrode could fail to light it but would not normally cause it to go out once lit.

Apart from the latest boilers where its combined the PCB has a main and an ignition sub board.

Probably either could cause your problem!

Which did you change?

Tony

 

[Sloop]

Could also be venturi in fan,on some early models some can be cleaned without removing the fan.

 

[rallyingden]

Tony

I replaced the main PCB

I did not change the spark/sense board or the electrode as I would have thought a fault with either of these would cause a lockout.

To be honest I have just found out that Vokera are offering a repair service for £169 inclucing call out, parts & labour.

I will ring them Monday.......

I will post the results of their visit when I have them.

Cheers
Dennis

 

[Sloop]

Ignition board maybe but not s/electrode were abouts are you in lancashire?

 

[gasbanni]

sounds like aps is dropping out.
Have you checked it with some manometer tubing ?
Boiler fires up aps drops out - boilers goes out without locking out ,goes through ignition sequence fires up then drops out again - back to square one!

If you keep blowing/sucking and boilers stays lit sorted.

 

[Agile]

sounds like aps is dropping out.
Have you checked it with some manometer tubing ?
Boiler fires up aps drops out - boilers goes out without locking out ,goes through ignition sequence fires up then drops out again - back to square one!

If you keep blowing/sucking and boilers stays lit sorted.

This is a home owner!

Do you really think that he is going to have a manometer and tubing or even know what it is?

As far as opening the combustion chamber and playing with an APS ( he is unlikely to know what it is anyway ) is concerned, I would suggest that it is inappropriate advice for a non CORGI anyway.

 

[gasbanni]

oops my mistake.
I did not realise it was a homeowner,
had I picked up on that, I would have offered no solution at all.
It was rather late when i posted the reply.

When I read the other replies I thought they were replies to a fellow engineer. My mistake.

Many years ago I asked corgi if it was acceptable for an electrician to fix an electrical fault on a boiler, the reply I received was yes, providing it did not affect gas safety, break in to a gas carrying pathway or involve work in the combustion chamber (poc therefore gas carrying component).
This answer was unacceptable, gas regs define work, what class of person can carry out work, and regs state apps must be left safe. Lets say a sparky replaces a pcb how can he adjust potentiometers to give correct gas rate on gas valve without contravening gas regs ?

Corgi suggested that I contact the headquarters of hse for a definitive answer, initially when contacted they said pretty much what corgi had said. Yet again the answer was actually somewhat at variance with what the regs actually say. Which is that any "work" on a gas "fitting" ( for the purposes of the regs a boiler is a gas fitting) must be by persons belonging to a class of persons approved by the hse, there is no mention in the regs of gas carrying pathway.
When I explained that the answer was unacceptable and didnt actually answer the question, they put me in touch with someone who had a hand in writing the regs.
Same question posed, the answer was along the lines that they didn't want to burden installers any further with having to gain electrical quals
as I was about to speak he said " I know what you're going to say regulation 26 something or other " the one about having carried out work and then leaving the appliance safe for use, how can a sparky do that ?"
In a nutshell the regs are very clear what work is, what a gas fitting is and who can do it.
Final answer was that one day some poor sod of an eletrician will do a favour for somebody fix an electrical problem, a fatality will result and the courts will decide the sentance.

So your correct tony, I should not knowingly give any advice on "work" (fixing) to "gas fittings" (boilers) to any one that's not registered and neither should you !

 

[Agile]

The answer to that is that I do not give any advice in relation to work on gas parts or anything that involves disturbing the gas train.

In the last few years CORGI have relaxed their view and only take the stance that work on the gas train or anything that affects it like safety devices or PCBs with gas affecting adjustments needs a registered person.

Because CORGI only made up generalised advice that was not always aplicable to every situation and I am able to think about every situation individually.

Tony

 

[gasbanni]

Maybe I wasn't very clear, The point I was trying to make is that The gas regs do not specifically talk about gas trains or gas carrying parts.
You know as well as i do they talk about "work" and "fittings" and for the purpose of the regs changing a thermister on a boiler is carrying out "work " on a "gas fitting ".
That's the hse's definitions, and I will reiterate had I know it was a householder I would not have offered any advice on fault finding or repairing (work)on the gas fitting (boiler), who knows how practical they are they might get a electrical shock!

As for corgi good riddance, they may well relax their view, Mike Thompson stating in print " Maybe Illegal gas fitters unregistered work should be considered as work experiance for the purposes of becoming registered !"

With people giving advice as to the fault I wrongly assumed they were giving advice to an installer. I would have never made the suggestion I did if I'd have realised they were the householder. we agree on that.

 

[Homesafe]

. Lets say a sparky replaces a pcb how can he adjust potentiometers to give correct gas rate on gas valve without contravening gas regs ?


So your correct tony, I should not knowingly give any advice on "work" (fixing) to "gas fittings" (boilers) to any one that's not registered and neither should you !

tut,tut ,

down boy!!

 

[DP]

I would be looking at the CH thermistor.