Suprima 50 cutting out - NOT locking out - buzzing relay?

[Darlodave]

I have a 4 1/2 year old Potterton Suprima 50 which does not lock out but sometimes will not fire on demand from the central heating (Hot water demand brings the boiler on though).

I've checked the room thermostat / tank thermostat and all appears fine at that end, however, I've noticed a loud buzzing coming from one of the relays on the pcb (yes, I've had the board out and resoldered all the poor solder joints). This buzzing happens even if there is only power on to the boiler and no demand from either the CH or HW (programmer set to off).

Any ideas or should I bite the bullet and replace the pcb??

 

[croydoncorgi]

If it's not the latest PCB, I know of NOTHING that will make it into a good, reliable one! Bite the bullet and Get Someone In to install the latest upgraded type (plus new wiring, etc.) (I assume you're non-CORGI.)

 

[gazthepottertonengineer]

problem lies elsewhere me thinks more than likely the auxilary switch on your 3 port valve

 

[Agile]

I have had a faulty one which buzzed.

The customer turned it off and I just replaced it!

That would happen on heating or hot water equally as the boiler does not know where its output is going!

Tony

 

[Darlodave]

Thanks for the info guys!

Just another thing to point out, when there is no call for heat but the boiler is powered, the buzzing of the relay on the pcb is accompanied by the 3 port valve operating!!!. Gaz, further to your suggestion, does this make sense? and am I barking up the wrong tree with suspecting the pcb to be at fault?

Cheers

 

[gazthepottertonengineer]

if the boiler isnt getting power when you have just the heating on then yes you are barking up wrong tree
and i would personally look very closely at the 3 port valve

 

[geoff@cetltd]

problem lies elsewhere me thinks more than likely the auxilary switch on your 3 port valve

If a relay on the pcb is buzzing, then there is a fault with the pcb, simple as that

 

[gazthepottertonengineer]

I have a 4 1/2 year old Potterton Suprima 50 which does not lock out but sometimes will not fire on demand from the central heating (Hot water demand brings the boiler on though).

??

If you read his original post his main problem is that boiler only comes on for hot water and not central heating which is why i said that it would be auxilary switch on 3 port

 

[geoff@cetltd]

I did read his original post

and, as I said, if he has a relay buzzing on the pcb, then the pcb is faulty

I didn't say it was the only problem and I didn't reply to the other fault as I know that there are people with more direct experience who are better set to help on that

 

[Agile]

Part of his posting was:- """This buzzing happens even if there is only power on to the boiler and no demand from either the CH or HW (programmer set to off). """

As I said, I have encountered a similar pcb fault of a buzzing relay and it was cured by fitting a new PCB.

Intermittent hot water OR heating would be either a faulty thermostat or motor valve not operating the call for heat microswitch.

Tony

 

[geoff@cetltd]

Nah und ?