Central Heating Boiler/Controller fault?

[anniemac]

I have an old but extremely reliable (until now) Thorn M54 boiler with Horstmann ChannelPlus controller. The system is fully pumped with no room thermostats and we have checked that the header tank is full. Yesterday we noticed that the controller display was blank. The fuse in the central heating switch had blown. We checked the controller connections but they seemed OK. We replaced the fuse. With the boiler thermostat turned right down, the display returned on the controller, but as soon as we turned the thermostat up the fuse blew again.

Would like to know if this is likely to be a boiler or controller fault (ie whether to call out electrician or heating engineer), also if it indicates terminal trouble in the boiler which we had anyway been expecting to have to replace in near future?

Thankyou in advance for your help

 

[ollski]

check that there is no water leak in the motorised valve or the pump electrics shorting it out. If the pump is getting tight this will blow the fuse due to the resistance.
In answer to your question a good plumber or heating engineer.

 

[anniemac]

Thank you for your quick and useful reply! yes i have had a look at the pump and surrounding pipework, also the valve. it is all very clean and dry.

not sure what you mean by the pump getting tight? is this something to do with the big screw on the front of it (Grundig pump) or something that goes on inside due to age? (the pump has also been there for many years but had shown no audible sign of wearing out..) could a failed pump fuse the system so quickly?? (the fuse went as soon as i turned up the thermostat to start the boiler up). Could a boiler fault fuse the switch (have very limited understanding of heating systems because it has so rarely gone wrong)?

it looks as if we have an expensive job ahead??

thanks again

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[ollski]

if the fuse fails immediately I would guess that you have a direct short circuit.....normally on an existing system this is caused by a small water leak in the places i mentioned, but equally it could be the boiler. price depends on which component is leaking. There is a fair chance you won't see any evidence of the leak without removing the covers on those components.

 

[AnonymousImport]

Turn the stat to off. Turn on the boiler and the clock. Go back to the pump, Is it turning(should be).
2.
turn the stat up
if the fuse has blown, make the appliance safe and remove the cover off the stat check tha there is on water damage or loose wiring. retest. If it still blows a fuse call a boiler engineer. U have traced the fault to the burner.
What is the type of the stat and burner.

 

[weargas]

What is the type of the stat and burner.

by the way she described it in her first post i thinks she's talking about a room stat not the boiler stat.

 

[anniemac]

thanks for all your advice.

in answer to 'Heating' as I said in my first post there are no room thermostats, just the one which is integral to the boiler (Thorn M54 - yes I know we are very backward here). The pump only runs when the heating is turned on; as soon as i do this by turning up boiler thermostat (or setting controller to 'on all day' with boiler thermostat turned up) the fuse blows. Therefore as all the visible wiring seems OK it seems likely that as Ollski says the burner is at fault? I'm not surprised after all these years. So I will (try!! and) get a heating engineer to come. i will probably be asking all you guys for some help choosing a new boiler next. if I want lots of hot water (family house) and I don't want lots of steam billowing past my kitchen window and back door then I think I need to stick with my conventional (and very reliable) type of boiler? Do they still make them as good as this one has been (don't care if it is less efficient, reliability is what counts)??

Thanks again

 

[weargas]

as I said in my first post there are no room thermostats

d'oh!!!!!!!!!!!!
that'll teach me to read posts more thouroughly!!