Boiler fires up on its own

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Hi Guys, just found this site and wonder if can help with a problem I have.

Please excuse my being vague about system manufacturers but this is an old system I installed and wired for my parents about 20 years ago as a solid fuel system. It was converted to a fully pumped gas fired system with a Gloworm boiler about 10 years ago. It uses a cyl stat, no room stat, 2 x 2 way valves and a 24hr 3 timezone programmer.

Right the system has performed faultlessly and correctly untill recently. The boiler then started to switch on and off at odd times throughout the day regardless of program setting, ie when set off on both hw and heating. The programmer was changed as it was the oldest part of the system and now switches both hw and ch correctly. However the hw proved to only funtion occaisionally. I then did what I should have done in the first place and checked the motor valve for the hw, it has gone. So motor removed and replacement on its way, (its the common type motor as used by honeywell although I think the valve was sold as wickes own label.
The system was wired conventionally and 2 the diagram in the boiler manual, although I cant explain exactly how its wired as it was 10 years ago and I don't have direct access to the system as I speak.

The boiler still switches on occaisionally even with the motor removed and the programer set to off.

Now the question is will this be down to the motor failure, as I'm assuming the aux swith is used to power the boiler, (can't remember exactly how it was wired, but if you lift the manual lever on either of the motor valves the boiler fires up.
Or is the whole top of the valve shot as I now suspect it maybe?
Or any other possibilities.

As I said sorry for the lack of info but I wont get back to this for a few days,
Cheers for any help offered :LOL:
 
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Even with the syncrohn motor out it fires up,? so must be microswitches in the valve ive seen it when there old and the insides are starting to go and water is weeping out the centre and causing the electrics to go a bit mad
 
What boiler have you got?

make and model would be handy to know
 
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Does anyone know who manufactured wickes own lable 2 way valve?
Looks like a honeywell to me but not sure as casing is un marked.
I'm suspecting I need the whole valve top.

What has just occured to me is that it could be the aux switch in the other valve thats firing up the boiler
 
Right I've taken a further look this again today and fitted a new synchro motor to the hw run. The system now works perfectly via the programmer and both valves open and close with the programmer switching on the boiler and pump.

If I operate the valves manually they fire up the boiler and pump.

But, the boiler still fires when it shouldn't

It also does this with the programmer removed fom its standard back plate.

It does have a room thermostat fitted, I had forgot.

The boiler is a glow worm 56 back boiler unit, (would this boiler have had a permanent live requirement?)

2 way valve for hw, 4 wire br bl gr or

2 way valve for ch "

pump

programmer

room stat

cyl stat

All wired up to a little choclate block wiring centre box

Does anyone have or can point me to a suitable wiring diagram for this set up so I can set it up from scratch?

Thanks,
B.
 
The boiler is a glow worm 56 back boiler unit, (would this boiler have had a permanent live requirement?)

Quote from Manual:

The boiler will only require a permanent live if a fire front with lights or ignition is to be fitted.

Does anyone have or can point me to a suitable wiring diagram for this set up so I can set it up from scratch?

It sounds as if you have an S-plan system; i.e. fully pumped with a zone valve to control HW and another zone valve to control CH.

Here is the wiring diagram:

8awjmvp.jpg
 
Thanks for the help, it is indeed the S plan basically, but when I wired this 15 years ago the mains feed went directly to the programmer and straight out to the wiring centre.

:D :D :D :D

However, just feeding back the outcome that may help someone else, it was the aux switch on the ch zone valve that was causing the problem.

Although I don't know the manufacturer of the zone valves, I can see where the info labels were originally placed. But they are long gone.
What has happened was that part of the plastic retainer for the overide lever had broken off and jammed the switch closed. This was intermittant when I first looked at the problem and not on the valve with the dead motor,but must have been made worse by my operating the lever a few times. Still all is now well, valve can't manually be left in open position but should the need arise I'm sure a tywrap will fix it,

Thanks again,
 

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