Hi,

I'm having a problem with my central heating boiler, the safety cutoff
keeps 'popping' out when ever the room thermostat is *not* calling for
heat. Looking at my system I can see the flow feed from the boiler
passing through the pump (high speed setting), through two 'T'
piece's, and then the motorised valve (and onto the rads). The two
'T' pieces are for (I think) a) a loop circuit and b) to feed the hot
water storage tank. There are also two gate valves on these two
pipes.

Can anyone give me ideas on why my system keeps cutting out like this?

How open should the two valves be? Should the loop valve be more
closed than the others?

Thanks in advance

Danny

PS: I've just flushed the system completely, used cleanser for a
week, flushed twice, re-filled and treated with inhibiter.
Boiler does not cut out when the room thermostat is calling for heat