Potterton Suprima 60 - starts up but then turns off.

[JimboT]

Hi All

Newcomer to this board, although I've read plenty of threads re the dreaded Potterton Suprima lock-out problems.

My Potterton Suprima 60 goes through its ignition sequence fine, the boiler starts up, with the flame igniting (while the green LED is flashing fast). Then it shuts off - repeats this sequence 3 times then goes into lock-out. I know the boiler is designed to turn off under certain circumstances, so have replaced both the temperature sensor and the overheat thermostat, still the same behaviour.

More in hope than expectation, I also changed the PCB, with a recon from CET Ltd. (good service by the way). And still get the same.

Not sure where to look next - any suggestions gratefully received.

Cheers
Jimbo

 

[Llan1observer]

flame rectification probe? not detecting flame

check electrode gap is 3-4 mm and not damaged, check for loose connections on electrode and earth wires.

 

[JimboT]

Thanks for the response - I'm no professional, I'm guessing that flame rectification is where the fact that the boiler is now lit is reported back to the PCB? So the PCB knows to NOT switch off the gas flow ...

Does this have anything to do with the HT ignition lead i.e. is that lead used to report the "boiler lit" signal back to the PCB?

 

[gas4you]

Yes, also make sure the earth connections are good.

 

[JimboT]

Thanks for the response Dave - I'll try replacing the HT ignition lead, and will also check that the earth connection is sound.

 

[ddk]

Make sure the electrode lead is pushed fully home on both the electrode itself, and the spade connection at the rear of the PCB. This boiler has only one electrode, which is used both for sparking and rectification (flame sensing). A poor connection on either the electrode or spade would allow the boiler to spark and ignite, but not to rectify and maintian the flame. Let us know how you get on

 

[JimboT]

Eureka! Replaced the ignition lead, and the boiler now ignites (as before), but then actually stays lit. Ignition lead is a standard part for Potterton Suprima boilers, part number 407753 (for Suprima models 30 to 80), and costs about £3.50. You can find a local supplier from the Potterton web-site.

gas4you and ddk, thanks for confirming that the lead handles both ignition and rectification, that was a great help.

Seems to me that it's definitely worth having a small stock of replacement parts for the bits that an amateur can quickly install (temp sensors and so on). For a few quid, you can then try a few basic things before calling in the professionals.

Of course, it's absolutely baking outside, who wants hot water at the moment ...

 

[gavinda]

as this requires opening the dreaded combustion chamber, perhaps amatuers should stay out or be well aware of what they may be undertaking.

 

[JimboT]

Yeah, point taken. I'm actually an IT bod, so am used to fiddling around with replaceable components - of course there aren't too many parts of a PC that might explode and destroy your kitchen (or worse ).

So, for any other amateurs reading this thread, if you have any doubts, call in a properly trained guy.

 

[SisterAbdullahX]

Yeah, point taken. I'm actually an IT bod, so am used to fiddling around with replaceable components - of course there aren't too many parts of a PC that might explode and destroy your kitchen (or worse ).

So, for any other amateurs reading this thread, if you have any doubts, call in a properly trained guy.

Not sure that being an IT bod would cut any mustard with Gas Safe Register, dude! If you ain't qualified, you're an amateur!

 

[Nevada92]

Make sure the electrode lead is pushed fully home on both the electrode itself, and the spade connection at the rear of the PCB. This boiler has only one electrode, which is used both for sparking and rectification (flame sensing). A poor connection on either the electrode or spade would allow the boiler to spark and ignite, but not to rectify and maintian the flame. Let us know how you get on

Brilliant advice - when you're replacing the board, it is very easy to not fully reconnect the HT lead - you have to look into it and make sure the spade connector is properly in - if not, it can make a lot of clicking, fire up three times and then cut out

 

[Fred Meaney]

Brilliant advice for me too. Once I made connection firm, boiler fired up properly. Thank you