Rads wont turn off

[Davey]

I have a Stelrad Ideal W RS430 boiler, a wall mounted Honeywell thermostat and a tank mounted Honeywell L641A1005 thermostat. The system is controlled by a Landis and Gyr timer which has separate switches for the CH and HW (on, once, twice, off) although central heating only can not be selected (only CH plus HW). Can someone please tell me what type of system this is?

Although the timer is set to HW only, the CH still keeps coming on when the HW does. Having searched this forum I believe there is a problem with the 3-port valve. This is marked “Sundial Y-plan 3 position diverter valve” and it has a lever on the side that is in the Auto position.

I took the cover off the valve head and found someone had jammed cardboard in next to the motor – any idea what this was for?

I can’t hear any noise from the motor but I’m worried this cardboard is already a bodge. Is it easy to change the complete valve head - I gather that some valves have a removable head while others require a drain down. The motor is marked “Honeywell 4000 2737-00 H8239” – how do I know which type I’ve got?

Apologies for the long post. Any help would be appreciated

 

[ChrisR]

Havin g the 3 port valve you have implies that you should be able to use a timer which will give independent control of ch and HW. It may even be possible with yours - a switch or lever on the back maybe.

Cardboard.... implies you need a new head or valve - or maybe just motor.

The Honeywell valves whose heads ARE removable (without getting wet) have a pimple on top about 1cm across. If just the motor's dead you can change that in either sort.

The valve spring-returns to HW only, MAN holds it in CH + HW.

 

[Davey]

Thanks for that ChrisR.

Have had a look this morning and there is no pimple on the top of the 3 port - just my luck

There is however an isolating valve between the 3 port and the HW tank (at least I think its an isolating valve - it has a square square shaft at the top the same as on a radiator bleed valve).

Would it be possible to change the valve head by closing this isolating valve? The valve head appears to be secured by four phillips screws.

 

[bengasman]

Be careful with changing valve positions as they could be used as bypass valves in which case the setting is rather precise. Too little your system can overheat; too much and your house is cold and your gasbill through the roof. Changing the 3-port valve is not that big a job, especially not if it is just the head, provided it is a standard 22 mm and accessible. Only try to do this yourself if you are sure you know what you are doing.

 

[Davey]

Be careful with changing valve positions as they could be used as bypass valves in which case the setting is rather precise.

How do I know if its a bypass valve or an isolating valve?

Changing the 3-port valve is not that big a job, especially not if it is just the head, provided it is a standard 22 mm and accessible.

Yeah - seems to be standard 22mm and is reasonably accessible.

Only try to do this yourself if you are sure you know what you are doing.

Unfortunately I'm not sure what I'm doing hence the questions on the forum. Are you saying it is a job for a plumber?

 

[kevplumb]

The Honeywell valves whose heads ARE removable (without getting wet) have a pimple on top about 1cm across. If just the motor's dead you can change that in either sort.

think chris has already answered that one