Problems with Apollo Fanfare Gas Boiler

[ARJHighland]

Hi, could someone in the know please advise on the following problem:

My Apollo Fanfare 50 gas boiler is controlled by a recently fitted Sunvic HW/CH programmer (to replace a faulty unit which had a broken display) along with HW and CH motorised valves and HW tank stat. On programmer demand it starts up ok but during running it continually switches on and off by an on/off electronic switching contact inside the boiler unit, generally it still runs ok but am concerned that this fault may get worse or burn out a switch or other controling device. I have checked the wiring connections to be ok. I believe that before the programmer was replaced the boiler ran ok.

Thank you

 

[D_Hailsham]

On programmer demand it starts up ok but during running it continually switches on and off by an on/off electronic switching contact inside the boiler unit,

The only things in the boiler which could turn it on and off are the Low/High thermostats and the pump overrun thermostat.

Does the problem occur with the switch in Low and High Positions?

If it occurs in one position, but not the other, you have a faulty low or high thermostat.

Does the boiler go off and then come back on a few minutes later?
Does the pump stop running when the boiler goes off?

If so the pump overrun thermostat is faulty.

 

[ARJHighland]

Thanks D-H for your response; since I posted the fault, the system appears to be working ok so I'll keep my fingers crossed for now. When the on/off problem did occur, it happened when on high or low setting. When the burner went off it was just for a about a minute.

Thanks again, I'll keep your contact in case it happens again.