Power to boiler suddenly dead

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Keith650

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Hi peeps,
Problem with my boiler. Bit long-winded but to explain: I have a Grant Vortex Pro external oil fired boiler. It is about three years old and has been running perfectly fine until now, regularly serviced and In great condition. I was away for a few weeks and turned off all the power to it from the switch in my airing cupboard before I left. When I got home, I thought I’d fire it up for a little while just to make sure it was all ok. When I switched everything on in my airing cupboard and made sure it was calling for heat, I went outside to wait for the boiler to fire up (normally takes a minute or two from switch-on), but it was eerily quiet. I double-checked the controls in the airing cupboard which were set as I usually do, and I could hear the programmer ticking away nicely (it’s an old Randall 4033) and the pump was running. I then took the panel off the boiler to check things there but no light to on/off switch and the test button and reset button did nothing. It felt like there was no electricity getting thru to the boiler at all.
I called my boiler man round to take a look and he tested everything as far as he could but was left scratching his head. He agreed that there was no power getting thru from airing cupboard to boiler but couldn’t figure out why. Nothing had changed in terms of wiring or switching but suddenly the boiler is dead. Everything else in the house works just fine - it’s just the stretch of wiring from the airing cupboard controller to the boiler that appears to have died.
I’m wondering if one of the following could be the cause :
1) The programmer/timer in airing cupboard could be faulty (it is very old) even though it is running the pump and motorised valves ok,
2) There is a separate fuse in the boiler itself which has blown (my boiler man doubts it as there is no power upstream of the boiler from airing cupboard)
3) Before my time, some joker has buried another fuse in a wall or floor somewhere and that’s blown - I bloody ‘ope not - can’t believe they would,
3) The boiler’s broke - doubt it as pretty bullet-proof appliance.
I probably could have explained it better but would appreciate any ideas as I’m a bit stumped right now,
Thank you.
 
You need a multimeter to check if your getting power at the boiler, if your not you need to then check if there's power going into the cable that goes to the boiler in the airing cupboard, if there is you've an issue with the cable between airing cupboard and boiler.

If there isn't voltage at the cable in airing cupboard then part of the system in there has failed and isn't providing the supply to the boiler
 
Get a different boiler man. I would be testing the orange wire on the zone valve for 230/240vac. If you have this, the there could be a break in then wire. I would also check the permanent live is there from the programmer.
 
The external Grants have a permanent live to them have you tried running it with service switch?
Also if you have been useing boilers own incoming power switch they are well known for sticking and not working.
As has been said multimeter required.
 
Hi Exedon.
Thank you for reply. If by service switch you mean test switch, then yes I have tried this. The entire boiler seems dead to the world. When I switch the boiler’s on/off switch to “on”, the indicator light doesn’t show and nothing happens. Similarly with the test switch. The reset button does nothing either There’s simply no power coming down to the boiler from the airing cupboard in the house. The timer, pump and motorised valves are working fine. I just can’t understand why the power cable down to the boiler has suddenly died. All very weird. We had a massive thunderstorm overhead the night before I decided to fire up the boiler, but it was all switched off at the time (at the airing cupboard). I did have to replace a fuse in the switch by the programmer/timer though which appeared to have blown. That’s why I wondered if the old timer itself had caused the problem even though it appears to be working in all other respects.
Keith
 
thomp1983 said:
You need a multimeter to check if your getting power at the boiler, if your not you need to then check if there's power going into the cable that goes to the boiler in the airing cupboard, if there is you've an issue with the cable between airing cupboard and boiler.

If there isn't voltage at the cable in airing cupboard then part of the system in there has failed and isn't providing the supply to the boiler
Click to expand...
 
It is not so much of a problem at this time of year.

But during the winter you should not turn off the power to a boiler as most have a circuit to fire up the boiler if the temperature gets close to freezing.

Most boilers would be seriously damaged if allowed to get frozen up.

I am not very impressed by what your engineer seemed to have checked. The boiler should have a permanent live and a call for heat which is made live when the time clock and thermostat are both calling for heat.

As the pump is running then I would first suspect that the permanent live to the boiler has failed. But there are different ways that the pump could be connected.
 
Overheat stat isolates all power to boiler. Usually top right on a Grant under a little black cap. If you press it
and it has tripped it will be a positive audible snap when it is pressed.
Boiler possibly firing and hot when power tuned off and nowhere for heat to go so trips out. Also check
water pressure if sealed system.
 
Thank you. I did try that but to no avail. I tried quick presses and long presses but it didn’t do anything make any sound.
 
Red reset button on burner at bottom of boiler. Hole on red cover of Riello burner. Press and see if fires up.
Other thing is vermin love to chew cables and have had happen a few times. As said check if power to boiler if yes then fault in boiler
if not before boiler.
You could fit a separate fly lead to test but isolate in cupboard before doing that.
 
Last edited:
I’m starting to get visions of a tradesman wanting to demolish half my house to try and find a hidden cable or spur that didn’t exist in the first place. Ker-ching
 
Keith650 said:
I’m starting to get visions of a tradesman wanting to demolish half my house to try and find a hidden cable or spur that didn’t exist in the first place. Ker-ching
Click to expand...
:ROFLMAO: :ROFLMAO: :ROFLMAO: . Just get a decent heating engineer or spark who’s competent in heating wiring.
 
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