Potterton Suprima

[belrac]

I have just had my Potterton Suprima upgraded to the new PCB (Part number 5111603) and find that when the system is calling for heat (HW or CH) the pump switches on, then the boiler fires up. When the boiler get to temperature it switches of the gas, overuns with the pump and then switches the pump off. After about 1 second the pump switches back on again and the gas re-ignites. Alternatively, the when the boiler gets to temperature it switches of the pump for 1 second and then restarts it.
The old board used to switch the pump on, ignite the boiler, when it reached boiler temperature it then turned the gas off but ran the pump until the boiler cooled and then re-ignited the gas (without turning the pump off). My understanding of how it should operate is that the pump starts, the boiler ignites, when the boiler gets to temperature, the gas turns off, the pumps keeps running until the boiler cools and then the gas re-ignites without any break in the pump cycle. Is the behaviour of the new board correct, it does not seem so to me, having a 1 sec stoppage and then restarting?

 

[Rob]

um....im not sure but does it matter?

 

[belrac]

It matters because the old style board used to switch the pump on and only turn the gas on and off when the boiler stat demanded it or until the there was no call for hot water or heating. i.e the pump ran constantly which when trying to sleep was ok as you got used to the drone.

Now it switches the pump off for about a second and then switches it back on. So it is still doing its job but the constant stopping and starting of the pump is irritating as the drone stops and starts which makes it difficult to settle down as you end up listening to it. BGas tell me that Potterton says this is correct but it seems like a design fault to me.

 

[Vic Spanner]

Yes it is the correct operation..