Optima 700

[Mbear]

Anyone had this fault before....

Ch comes on with no demand intermittently, the cust got up at 2am to use the toilet and noticed the rads where hot, the timer is set for 7am-11am and then 5pm-11pm. The integral timer was replaced 2month ago I presume bcos the cust complained about the same issue.

My thoughts are it's got to be the frost stat making
or the board relay sticking on after the 11pm off time. Also the pilot went out for some reason overnight.

I've ordered the internal frost stat and the interrupter stat for Monday.

Penny for ur thoughts folks? What else if anything could cause this?

 

[Billy Bob Bob]

a knackered ch thermistor, especially if its been leaking take it you have strapped the clock just to prove

 

[Mbear]

Strapped?

I can't see the ntc doing this(no leaks anywhere on the appliance either)

I've got a spare clock in the van, I suppose I could stick It in along with the stats on Monday.
My initial thots where this, clock then frost stat then board, as I say the clocks been changed not long ago. Would a faulty ntc keep the pump and fan running and gas valve lifted?

 

[Billy Bob Bob]

Strapped?

I can't see the ntc doing this(no leaks anywhere on the appliance either)

I've got a spare clock in the van, I suppose I could stick It in along with the stats on Monday.
My initial thots where this, clock then frost stat then board, as I say the clocks been changed not long ago. Would a faulty ntc keep the pump and fan running and gas valve lifted?

dont know if they would on a ferroli,but they will on a ariston but as said normally if its leaking,but would try a ntc anyway before pcb v.cheap ntcs in abkot and bes for this combi,also pcb but get type off sticker on board