Combi boiler cycling

[Dan_PF]

If the target flow temperature is 65C then no it shouldn't be tripping even if it overpowered until the flow temperature reaches 65+5, 70C it will also trip/ recycle if the flow/return temp differential (dT) is greater than 30C, if its cycling at 50C then the return temp must be a unlikely 20C or you have a circulation problem, if the DHW side is OK then unlikely to be the circ pump, could possibly be the diverter valve. Try setting the target flow temp to 75C.

I think it must be thermostat that is causing it to click off so quickly then. When I increase the temperature on the thermostat from the current room temp, it has no issue with the flow going up to 70 and working as expected.

I’ll try the minimum on time today and see what that changes.

 

[Mister Banks]

Bear in mind that your thermostat will be trying to avoid over heating the room so if you set the room temp to 19c the thermostat may turn off at 18.5c and allow the residual heat in the radiator to continue to heat the room. It the room has not reached the set temperature the thermostat will fire the boiler again for a short period until the temperature is reached. This saves overshooting the set room temperature and saves energy.

Another thing to know is that a radiator may feel lukewarm to the touch but could still be emitting 20c+ into the room.

 

[Dan_PF]

Bear in mind that your thermostat will be trying to avoid over heating the room so if you set the room temp to 19c the thermostat may turn off at 18.5c and allow the residual heat in the radiator to continue to heat the room. It the room has not reached the set temperature the thermostat will fire the boiler again for a short period until the temperature is reached. This saves overshooting the set room temperature and saves energy.

Another thing to know is that a radiator may feel lukewarm to the touch but could still be emitting 20c+ into the room.

Yeah that makes sense. Ultimately it is doing its job, I’m purely worried about the wear on the boiler for it cycling on and off in short times.

I’m wondering if the TPI is messed up. It did all of the “learning” when we only had two radiators connected. And I'm not joking, we may as well have had all the windows and doors open. Maybe it thinks it’s going to get cooler quicker than it will do now, hence the heating trying to kick in.

I might give them a call and see if that is worth resetting.

 

[Johntheo5]

If you set a minimum on time of 2 minutes and if the boiler is not reaching the target temp + 5C and if the roomstat isnt satisfied then the boiler should run for 2 minutes, period.