Boiler always on Following power cut

cupan_tae

Hi All

Just discovered this in the last few mins but our outside oil boiler for heating & Hot Water is always on.

We had a power cut this morning while Misses Cupan_Tae was in the shower - (All lights and appliances went off for 10 - 15 seconds. The MCB did not trip my guess at the time was mains power outage or similar (no neighbors to check with)

Since then (I think) the boiler is always on - even if\when the on\off\timer is in the neutral (off)- position. The only way I can turn it off is via the trip switch on the MCB

I tried resetting the boiler (pushed reset button).

From other reading I'm doing I'm guessing its time to start testing some of the components and boxes between the on\of switch in the kitchen and the boiler itself

If anyone has some input or suggestions fire away

Thanks
Cupán

Wearb

Looks like timer faulty. Not cold enough for frost stat to keep it on. You will need output from timer tested.

Just another thought, sticking motorized valve can cause same problem, but it shouldn't be able to bypass timer.

jimf

my guess would be motorised valve as well

agusta

If wired correctly a motorised valve stuck in the on position[or manually put in the on position] will by pass the timeclock.so it looks like you have a motorised valve issue.id be checking the motorised valve first,then frost stat,then timeclock
ps.your frost stat needs to be replaced and relocated to a different poistion

cupan_tae

Thanks for the replies lads

Update: When we opened up the timer we were seeing live with the switch in any position. Then we opened up the frost stat we could see some blackening around the board inside. With the frost stat bypassed everything works fine.

So will look to replace frost stat soon and yeah tidy up things aswell (mount frost stat nice and tidy in the front somewhere) its position has led to heat from the boiler warping all the plastic casing on the frost stat over the years.

Cheers again lads appreciate replies

Wearb

cupan_tae wrote: »

its position has led to heat from the boiler warping all the plastic casing on the frost stat over the years.

That's a lot of heat. Perhaps it was leaking hot gasses from the heat exchanger at some time or even still.

agusta

Wearb wrote: »

That's a lot of heat. Perhaps it was leaking hot gasses from the heat exchanger at some time or even still.

I agree,something is not right.could the frost stat have melted from the wiring inside the stat itself

jimf

I disagree just for the sake of not agreeing with ye 2