Potterton Suprima - Short Cycling?

[3guk]

Hello Everyone,

Was hoping for some advice in terms of a potterton boiler that as soon as it has warmed up (after first turning on and running for 12-20minutes) starts to short cycle and fire every 5 minutes or so (for around 1-2minutes)

The PCB was replaced a few years back and most recently the NTC sensor and the fan was replaced (fan bearings had gone bad) - it doesn't seem like the NTC sensor has done anything to improve or change the issue. A previous engineer had even left the NTC sensor floating around in the case rather than being in the correct location in the dry pocket.

We've also experimented with different pump speeds trying all 3 modes and the result is pretty much the same.

Are there any other things that it could be - I know the PCBs are notorious for causing problems, but given no error lights and it working well until it's reached it's temperature, I wondered if something else could be causing it ?

There's no issues with hot water nor the temperature of the radiators - just seems to cycle an awful lot compared to previous years of usage.

Thanks in advance

 

[Agile]

My initial reaction is that it is probably correct for your installation. You seem to have decided there is some problem! So what would you expect?

However if I was investigating it then I would be measuring the power input whilst firing first.

And then plotting the return temperatures.

You have not given any information on the property or the heatloss.