Potterton Performa 28i keeps cycling on and off

[tukky142]

Hi my potterton works fine on HW. But when i put the CH thermostat up high and the system is cold the boiler pilot lights for a few seconds and then goes off for a couple and then back on for a few seconds and so on. Surely the boiler should go on full until it reaches the thermostat temperature and then start cycling.

Anyone got an idea what it is?

Thanks in advance

 

[hungryhippo]

Does it only cycle when its cold?

 

[Agile]

Thats often caused by a lack of flame detection as a result of wrong gas settings.

However these need to be checked by a competent person who would normally be CORGI registered!

Tony

 

[tukky142]

no it doesnt only do it when its cold it keeps doing it even when rads get warm.

I think I will have to get someone out then to check the gas settings

 

[tukky142]

I have asked my boiler repair man to come out but he cant make it for a week. After explaining the problem he said it could be the air pressure switch - what do you think?

Just to re-confirm problem - When on CH the boiler fires up, flame light comes on for 6 seconds and then goes off for 6 seconds then back on and so on ( rads take a long time to heat up as boiler never gets on full power. The ignitor for the ignition electrode at the front is clicking continuously whilst flame is coming on and off. (It doesn't click when on HW)

When on HW the boiler fires up correctly light stays on and the water is nice an hot until tap is turned off.

Does the air pressure switch monitor on both ch and hw?
How can I check if this is the problem - can you do a continuity check.

 

[tukky142]

reading some other threads on another site it appears that because the ignitor keeps clicking my boiler has a flame recognition problem - where is the flame recognition device? - is it part of ignitor?