Heating always on

[dutch_delight]

Hi everybody,

I recently moved into a house and last week the central heating came on and never turned off. The only way to turn it off is by turning the thermostat right down. The water does turn on by demand but the CH is taking no instructions from my programmer.

When setting the CH to on, the indicator light turns on and when turning it off it goes out. This makes no difference however, the boiler keeps heating the CH.

Funny thing is, there is a thermostat in the outhouse which works and a similar one in the hallway which does not seem to work.

My boiler is a Myson Orion (1989) and is situated in an outhouse.
My programmer is a Siemens RWB9

I'm thinking the programmer has developed a fault?



Any help greatly appreciated as money is a bit tight at the moment.

Rich

 

[Newboy]

It sounds more likely that )assuming you have one!) the three port valve is not closing of the heating port - have a look around your hot water cylinder they may be a valve on the pipework with a motorised head on it.

When the system demands either HW or CH the valve should close/open as required.

If you find one of these post back or have a search - very common problem (especially after the CH has been off for a few months)

The thermostat in the outhouse is probably a frost stat to stop the boiler freezing

 

[ollski]

Would hazard a guess that your prime suspect should be the frost stat, turn it down to 1 deg and see what happens.

 

[JoeBid]

Oddly enough I've got exactly the same symptoms (but different hardware) - the programmer is a British Gas UP2 (which I think is the same as a Drayton LP722 or similar.) The motorised valve is marked model BGMVSP-23 - again, I think it's a rebadged Drayton unit. No frost stat that I can find.

I must admit I'd asusmed the programmer was asking for heating all the time, even though it was set to off, and was therefore dud. But from what you're saying I gather that a dud motorised valve can cause this? Is that correct?

cheers -

 

[namsag]

YEP dud valve will cause that , the plastic arm in those valves sometimes break jamming the valve movement in the

 

[Agile]

Any help greatly appreciated as money is a bit tight at the moment.

Rich

I thought money was always tight in Yorkshire but then you are called "Rich" !

It needs a little electrical testing to see if its the programmer or the motor valve which has failed.

Tony

 

[JoeBid]

It needs a little electrical testing to see if its the programmer or the motor valve which has failed.

Tony

Just done a quick check - there's 240v coming into the room thermostat even if the programmer's CH is set to Off.

Does that mean the programmer's dud? Or is there something else I should be checking?

Ta for everyone's help

 

[Agile]

IF it has been correctly wired then it sounds as if the programmer is indeed faulty.

Tony

 

[JoeBid]

IF it has been correctly wired then it sounds as if the programmer is indeed faulty.

Tony

Cheers. I think it was correctly wired - as far as I know it was working OK previously, but then we've only recently moved in and haven't had much call to test the heating

New programmer time, methinks. Many thanks - owe you a pint

 

[dutch_delight]

I think my tread has just been hijacked!!!!

Anyway, I do have a quite complex arrangement around the tank so i'm gonna post a picture of it later today.
I'll also do some more tests to see if the valves do shut. But to be honest, not even sure what im looking at.

cheers for all the help
R

 

[John M]

"Complex" is my middle name

 

[dutch_delight]

'Trouble' is mine, and not because I am.

It seems to have gone away now. I turned the thermo right down to 0 in the outbuilding and turned it up in the hallway. The heating and water now seem to come on, on demand.

(We'll see tonight when i get home and the house will be boiling ofcourse!)