Radiators wont turn off

[Davey]

We have a gas powered hot water and central heating system comprising of a Stelrad Ideal W RS430 boiler, a wall mounted Honeywell thermostat for controlling the room temperature and a tank mounted Honeywell L641A1005 thermostat for controlling the hot water temperature.

The system is controlled by a Landis and Gyr timer which has separate switches for the central heating and the hot water, and each switch has four positions (on, once, twice, off). All winter the system has been set so that the central heating and the hot water come on together twice a day. With the recent warmer weather we turned the heating switch to the off position but it keeps coming on twice a day when the hot water does. We have also turned the wall mounted thermostat right down but this has had no effect.

Having searched this forum I have a feeling there is a problem with the 3-port valve. Does this sound reasonable or is there something else that could be causing the problem?

The valve is marked “Sundial Y-plan 3 position diverter valve” and it has a lever on the side which is in the left hand (Auto) position. Assuming it is the valve that is causing the problem, can the valve be operated manually by moving the lever and what position should the lever be in to switch the heating off?

Is it easy to change the valve or would we be better getting a plumber in? At the moment we can live with the problem but we couldn’t manage without hot water!

Apologies for the long post. Any help would be appreciated

 

[kevplumb]

it's likley to be either the valve stuck or the actuator has given up the ghost

 

[Davey]

Thanks for the quick response Kevplumb.

How do we know if it is the valve or the actuator and how do we go about fixing it?

Can the valve be operated manually by moving the lever and what position should the lever be in to switch the heating off?

 

[kevplumb]

if you move the lever it put's the valve in mid pos
ie both hw/ch

take the actuator off and see if it moves when you select hw only

check the valve spindle is free while you have the head off

 

[Davey]

Sorry to sound thick but I really haven't a clue here

If I understand correctly you are saying:

* move the lever to the mid-position which will put the valve in the mid-position.

* remove the actuator (the grey box on top of the pipes). Presumably this prises off as I couldn't see any screws holding it on?

* see if the actuator moves when I select HW only on the Landis & Gyr timer

* check if the valve spindle is free - presumably this is on the pipes and is visible when the actuator is switched off?

I will check these tonight and report back.

Thank you for taking the time to reply - its much appreciated

 

[Favno2]

Hi Davey,
After reading your postings it looks like I have exactly the same problem with my boiler.....
Did you manage to fix it?

Regards
Paul