Glow-Worm 18HXI - Continuous Pump Running

Hi

I have a Glow-worm 18HXI installed in the garage, which is a 'lean-to' on the house. For over a week now, in non-timed periods, the boiler fires intermittently for about 10 seconds, and the pump has been running continuously. I suspect this is the on-board frost protection kicking in, as the garage temperature has been quite low. The ambient temperature is now back to 6 or 7 degrees, but the boiler is still running the pump non-stop. I understand that the stat. has quite a wide temperature band, and may need ambient of around 10 degs before releasing the pump. The boiler is also protected by an external frost stat, adjacent to the boiler, but this hasn't activated. Is there any way of re-setting the on-board stat, so the pump goes back to normal operation ?

Thanks.

on the board there ar 4 dip switches numbered 1-4 make sure number 2 is off i number 3 sets boiler temp to 70 degrees so goes no higher make sure rest are off.check m.i.

u could be right tho, pcb frost protection is stuck on too after the last month of weather

I have come across this twice. The only thing that sorted it was a new main PCB and a interface pcb (the little credit card size pcb)

Thanks, guys.

I'll have a look at the DIP switches, but nothing in the boiler has been changed since it was installed. I did try switching everything off for 30 mins or so, and then restarting, but that didn't make any difference. Is the frost stat. a separate item - could that be faulty ?

Just to complete this topic, I finally traced the fault down to a sticking microswitch in the MV in the HW circuit. I disconnected it, and it now works fine on the CH side. Now just the MV to sort out ..

Thanks to those that responded.