Drayton Mid Position Valve

[chenojoe]

Hi All,

Recently we have noticed that when the hot water comes on so do all our radiators. The mid position valve was replaced last year but I think this may be the cause of the issue. It may well have been happening all over winter but had not noticed as the heating was on at the same time.

When both the hot water and central heating are off it appears as the photo.


When I turn the hot water on though rather than moving to the "W" it moves to the mid point


Does anybody have any ideas why this is happening and what I can do to correct it?

Many thanks
Joe

 

[Echo the husky]

What position does it go to when only heating is selected (and room thermostat is turned up)?

What position does it go to when the entire electric supply to the heating system is switched off? (such as at the main isolator/switch fuse or fuse box)

 

[AGAS]

where did you get that name from echo ? ,and what part of devon you live mate ?

 

[Echo the husky]

Echoshock is my husky fursonas name, :3 but Echo is what everyone online calls me. The echo bit comes from my interest in old radios and televisions and is taken from the EKCO company, and the shock bit is from being a sparks... I live near Cullompton.

If the valve is moving to the mid position power must be being applied to the white wire (heating on). This should not happen with the heating off. To get the valve to H as in your first photo, power needs to be applied (at least initially) to both the grey wire (hot water off) and the white wire (heating on). The valve will then stay in that position whatever, for as long as power is applied to the grey wire.

With only hot water on (and cylinder stat calling for heat), the valve should have no power to the grey or white wires and should spring return to the hot water only position

Can you post a photo of the wiring where the valve is connected into? Should be easy to see then. Many issues with Y plan systems are due to incorrectly connected wiring.

I'm going to guess the white wire has been connected to hot water on instead of heating on. So when the cylinder has reached temperature, power will be already applied to the white wire from the programmer, and when the cylinder stat clicks off, the stat will connect power to the grey wire on the valve and move it to heating only. It then stays there as per the first photo.

 

[chenojoe]

Hi,
Thank you very much for your advice.
I have opened up the wiring box and have attached some photos. I am not sure if the house wiring is back to front and therefore the valve is working incorrectly.

Appreciate any help.
Thanks

 

[Echo the husky]

Well that all looks correct, can you post a photo of the wiring in the programmer?

 

[chenojoe]

The programmer is a Hive type system.

Attached is a photo and the wiring guide. Having no connection to number 2, do you think that is the problem?

Thanks

 

[Echo the husky]

No, connection 2 is heating off which is not used for Y plan systems (in fact it's rarely needed at all) Also:

What position does it go to when only heating is selected (and room thermostat is turned up)?

What position does it go to when the entire electric supply to the heating system is switched off? (such as at the main isolator/switch fuse or fuse box)

At the moment I suspect a problem with the Hive receiver.

This is easy to test:
Electricity off, mark the wire connected to hive terminal 3 with tape so you know which one it is, and connect it into the terminal marked L disconnect the blue and yellow wires from the hive base and insulate them so they can't touch anything.

Fit the hive unit back on the base for safety and switch the power on, the hive won't do anything now and hot water will be permanently set. The valve should now be at W and the boiler and pump will run when the cylinder stat is calling and will stop when the cylinder stat has reached temperature. You can turn the cylinder stat up and down to test. The valve should should be in the W position at all times and should not move at all. Ii it works correctly, the problem is with the hive, if the valve is still moving to the mid position then some testing with a meter will be required, though it might be easier at that stage to call an engineer out.