Radiators always on with Hot Water

[stucampbell007]

Here's the situation.

I had the central heating turned off for a couple of months. I turned it on briefly to dry some clothes over a radiator. Now the radiators are on permanently

The boiler is constantly flashing green, which I believe means that it's being asked for hot water.

I turned all the radiators off so the house didn't get too hot but I recently discoved that the central heating pump is running continuously, which I guess can't be economical or healthy for the pump's longevity.

The only way I've been able to stop it is to turn off the power to it - either at the main fuse box for the house or by switching off the power to the boiler downstairs.

Fortunately at the moment we don't need the heating on so I can just turn the power back on when we need hot water but I don't suppose resetting the boiler this way each time is particularly clever.

Through my googling it seems the problem could be with the "mid position valve/actuator"

This is the setup of our system under the hot water tank in the bathroom -

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• stucampbell007
• 25 Aug 2008
• 1

And this is the type of actuator -

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• stucampbell007
• 25 Aug 2008
• 1

I've removed these from the pipework and checked that the spindles move freely in the valve - as suggested in some posts - and both move quite freely.

Questions -

1. What causes the CH to run continuously - the control, the boiler or the actuator?

2. How would I check that the actuator valve was working? Can this be done manually?

3. In the setup above, which of the Drayton valve actuators would be responsible for the CH or is it both?

I've replaced the PCB in a Suprima boiler before - this is a Suprima 50L - and done some plumbing, not for CH though.

I imagine I'll have to get somebody out to do anything more serious than replace the actuator valve, but I'd like some ideas before speaking to a plumber. To be forewarned is to be forearmed, as they say.

Many thanks.

 

[shambolic]

If the heating is coming on when on for hw only the ball in the ch valve will have dirt on preventing it closing the whole way. If the boiler and pump are on 24-7 when the clock is in off position then the end switches in the actuator will be seized keeping power to pump and boiler at all times.
Depending on the wiring it will be the grey and orange wires that are these switches. Turn off power and disconnect a grey at your wiring centre from one valve at a time putting power back on to see if pump and boiler switch of, this will identify the valve that is stuck.
Buy one fae Plumbs or Hrpc etc and clip on the head and wire it like for like in wiring centre (do one wire) at a time.

 

[shambolic]

The way the actuator works is that it has a permanent live at one end of the switch just waiting for the motor to make the switch to supply 240v to the pump and boiler. If this switch is closed circuit it will continously send power to boiler even when timeclock is off.

 

[ChrisR]

That make/model of valve often leaks trough the shaft which makes it seize.
In that case you'll need a whole new valve.

 

[shambolic]

It depends on what the problem is as he is not clear whether the valve is coming on for ch when hw only asked for or on 24 hrs.

 

[stucampbell007]

Thanks a million for the swift response.

On the photo, would it be the lower of the two actuator valves which would be controlling the CH?

I ask because the top one came off the pipework very easily but the lower one in the cupboard seems to be stuck. I didn't force it as I didn't want to break the plastic casing. Now I'm wondering if it's leaked as ChrisR suggests, and this has caused it to become stuck.

However, if the problem is with the upper one, then that wouldn't make sense.

 

[shambolic]

Just follow the pipes although the top one looks to be going up to the cylinder flow!
Does the bottom one have the same wee button at the side to remove the valve?
If so just push it in and remove valve, if not it is an older type which doesnt have the removable head.
Can you tell me if it is the problem of heating coming on with the hw or the problem of the timer being in off position for both and the boiler still comes on as this will tell us the exact nature of the problem

 

[stucampbell007]

Yeah, sorry for the confusion. At first I thought it was just coming on with the HW but I'm now certain that CH pump has been running continuously.

The green light is constantly flashing and the CH pump runs, then stops briefly, then starts off running again, and it's extremely hot to touch.

I've just taken the second actuator valve off - after a bit of a struggle - and, indeed, there's a rust-coloured stain on the back of it so it looks like the valve is leaking.

This means the valve and actuator will need replacing, right?

 

[shambolic]

Yeah, sorry for the confusion. At first I thought it was just coming on with the HW but I'm now certain that CH pump has been running continuously.

The CH pump is running all the time, irrespective of any settings on the controller. It only stops when the power is turned off to the heating system.

Right this means its an actuator problem (the white electrical bit) look at my previous posts for testing this. start with tracing each valve so you know what wires are from which valve. Turn power of or remove fuse from spur unit. Both orange wire and grey wires will be linked together by colour. Remove one orange and one grey from the same valve keep them in atmosphere not touching anything and turn on power to see if pump runs. If it still does them it is the other valve that needs replaced if it stops then its thw one you disconnected. (hopefully the hw type as it soundslike the removable head type)

 

[stucampbell007]

I've just taken the second actuator valve off - after a bit of a struggle - and, indeed, there's a rust-coloured stain on the back of it so it looks like the valve is leaking.

This means the valve and actuator will need replacing, right?

Any idea of a ballpark cost for this?

 

[shambolic]

Not really
try this
http://www.uk-plumbing.com/acl-drayton-invensys-2-port-valve-679-h30830l1-22mm-p-1423.html

Will involve draining system to change or using a bung kit bit more of a job than just the actuator. I would put a honewell 2 port valve in as more reliable and easier to work on in future.
http://www.plumbnation.co.uk/site/honeywell-v4043b-22mm-2-port-valve/

The 2 links were googled in seconds try locally for yourself mate!