Radiators on when controller and room stats off

[copper-sid]

hi all

i have recently discovered that the radiators are hot when the the controller is on the off position and the only way to turn the heat off is to turn down the individual radiator thermostats. the controller appears to be coming on and off at the set times.

also when the controller is in the on position and the room stats are set on low temperature the radiators are still hot unless the individual thermostats are turned off.

i have a large house with 2 x ideal classic boilers. there are 2 x cotherm room stats one for upstairs and one for downstairs. there is one horstmann channel-plus controller. the entire system is powered by what is described as an industrial-sized grundfos pump. there is a valve in the downstairs feed pipe and a valve in the upstairs feed pipe

anyone have any idea what the problem might be please

many thanks

sid

 

[ChrisR]

when the controller is in the on position and the room stats are set on low temperature the radiators are still hot unless the individual thermostats are turned off.

Tha rads will be full heat until the room is up to temp- that's the idea anyway. Th rad valves do pack up evenually depending on make etc. How old and wghat make?



The boiler/pump will be turned on by the VALVES in the circuits. The valves will be opened by the horstmann + the room stat. SO either the valves are stuck open (could be enough to turn the boiler on or not quite enough, but still pass water), OR the electrics have gone awry.
It will need a bod with a voltmeter to be sure.

 

[copper-sid]

hi

thanks to chrisr for the suggestion about valves being stuck
is there a way of telling if they are stuck and if stuck do they need replacing or can they be unstuck

cheers

sid

 

[copper-sid]

hi all

with nothing better to do i have just been watching the central heating system as described in my first post above.

curiously the controller is in the off position...the 2 room stats are almost switched off....some of the danfos radiator stats are off and some are on

surely in this scenario you would expect no heating no hot water and everything off

well i found that the boilers are still igniting intermittently....the pipes are still hot...and the on radiators are still hot !!

is there a logical explanation please

many thanks

sid

 

[cozzmic]

If you have motorised valves you've got one which is part open and/or the micro switch is knacked or the motor in the valve is jammed on and the switch is activated.

 

[copper-sid]

hi

thanks coz.......sounds like i should look at the valves
i have 2......they are honeywells and are 2 port in line with the upstairs feed and the downstairs feed

do i simply replace both or is there a way of testing/opening/repairing

i am grateful to the useful suggestions so far and i feel the enemy is about to be caught !!

cheers

sid

 

[copper-sid]

hi all

just a quick mention my system has frost protection and the boiler does fire in short bursts

however in the past the radiators have always gone off when the controllers is off or the room stats are down

cheers

sid

 

[ChrisR]

...the 2 room stats are almost switched off....

So they are entirely, 100%, ON!

 

[copper-sid]

hi

the 2 room stats are as low as they can go

the heating should not come on.....but it does.....and even if the controller is off

sid

 

[ChrisR]

Sounds like the programmer has packed up then. Or that frost stat - turn it right up too - knob may be under a cover.

Try this:
Turn the power off to the heating. The 2 valves should return to cosed, by spring power. There's a lever at the end of the valve which should be pointing to Auto. If you push the lever towards "man"you should be able to feel the spring pressure, returning the lever to more or less where it cam e from.

 

[copper-sid]

hi

thanks for suggestion about controller being knackered perhaps....although it appears to be coming on at the right time set and going off at the right time...???

as for testing the valve in the manner described please tell me what it means if the valve springs back or does not spring back

will this be a definitive answer as to the which item is at fault

many thanks

sid

 

[copper-sid]

hi

oops...sorry...forgot to ask which position is valve closed and which position is valve open please

at the moment with the controller now off the both valve levers are pointing to the auto position

cheers

sid

 

[copper-sid]

hi all

i have now found that the valve in the upstairs flow pipe appears to stay in the manual position when pushed that way. the valve in the downstairs pipe springs back to auto position when pushed

what does this mean please

the valves are honeywell v4043h1106

cheers

sid

 

[ChrisR]

the valve in the upstairs flow pipe appears to stay in the manual position when pushed that way

It's stuck open. TRy undoing its 2 fixing screws a little - It might then spring return. If not, you need a new head.

 

[brumylad]

don't forget to isolate the electric first.

It sounds like the valve needs a new motor.