Central Heating on for 45 secs and off for 75 secs

[Peter19Scott]

Hello,
Wonder if anybody can help me, I have a Ferroli F30B combi and the heating system is playing up, the room stat calls for heat and the boiler ignites the boiler remains on and heats the water, the rads become hot but then the boiler is cutting in and out. It ignites for 45 secs and goes off for 75 secs. I have bled all the rads and there is no air in the system and the main pressure gauge is displaying 1.5 Bar. Has anyone got any ideas what could be causing this?

 

[ollski]

Probably a sensor fault, but quite a few things can cause modulation faults.

 

[Agile]

The boiler should ignite and then keep the flame on but reduce the size of the flame as the return gets hotter.

If its not reducing the size of the flame then the most likely problem is that the gas valve needs setting up properly but this is a CORGI job.

It could also be that you have too few radiators and the boiler is set on maximum power output. This is a common commissioning error.

Tony

 

[Razor900]

Or do you have thermostatic valves on all the radiators?

 

[Peter19Scott]

Or do you have thermostatic valves on all the radiators?

No there is a radiator in the hallway that has standard valves on and two towl radiators that do not have TRV's on the rest all have TRV's on

 

[Agile]

The boiler should ignite and then keep the flame on but reduce the size of the flame as the return gets hotter.

If its not reducing the size of the flame then the most likely problem is that the gas valve needs setting up properly but this is a CORGI job.

It could also be that you have too few radiators and the boiler is set on maximum power output. This is a common commissioning error.

Tony