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?
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?