Mixed underfloor heating & radiator zone problems

[averagejoe]

So I have underfloor heating in kitchen and utility Zone1
Underfloor heating in living room Zone2
Radiators in hallway & bedrooms plus heated towel rails in both bathrooms Zone3
The problem is switching on heating in Zones 1 or 2 is also heating up Zone 3 the radiator in the hallway closest to the living room and the next bedroom you cannot put your hand on as they are so hot I have checked that the Drayton valve actuator which is moving other that that I have no idea if someone could help I would appreciate it thanks

 

[CountryFan]

Sounds like the zone valve is passing/not closing properly. When all at rest check the zone 3 valve position, if it’s at a then could be the actual seating.

 

[averagejoe]

Hi thank you for your advice the lever is working as per your advice if I push manually there is tension on the lever and it returns to it's rest postion

 

[CountryFan]

Hi thank you for your advice the lever is working as per your advice if I push manually there is tension on the lever and it returns to it's rest postion

Sounds like it’s the ball/paddle passing then

 

[averagejoe]

OK I have no idea what that is could you explain it / does the Drayton valve need replacing...is it time for a plumber?

 

[CountryFan]

OK I have no idea what that is could you explain it

Ok, so when the valve is opened via the thermostat there is a paddle inside that allows heated water to flow, and when closed the heated water is nominal longer sent via that valve. If the paddle doesn’t seat correctly, the heated water from another zone it can pass into that zone

does the Drayton valve need replacing...is it time for a plumber?

Possibly. With everything cold and nothing calling for heat, call for heat in a zone other than the potential failed one, feel the pipe on side B, if it heats up and B is still closed, then it’s passing.

 

[averagejoe]

OK please bear with me how do I differentiate which pipe is B

 

[averagejoe]

This is my system with underfloor heating on left right in front is the Drayton valve

 

[averagejoe]

Sorry underfloor heating manifold on right

 

[CountryFan]

OK please bear with me how do I differentiate which pipe is B

You have a Drayton 2 port valve, a is closed and b is open. Have a look on the side of the valve and it tells you

 

[averagejoe]

Right I have managed to take a photo of the valve as it's position made it difficult to see.
With zone1 running it looks like this as you can see in photo the switch is on A the pipe on the left is hot

 

[averagejoe]

To make it clear the pipe on the B side is hot

 

[CountryFan]

To make it clear the pipe on the B side is hot

So it’s likley passing then and needs to be replaced.

 

[averagejoe]

OK thank you very much for your help sorry I've been a bit thick but the top of the valve was very difficult to see do I need a whole new valve or could I get away with just replacing the top half thanks once again