Motorised Valve ?

The central heating has been playing up for a few days now. I can manually run the system using the lever on the motorised valve. i took the motor off the valve and checked it using the thermostat and it seems to work fine, i have tried turing the valve and that is easy to move. The main problem seems to be that when i turn off the hot water through the day and just have the radiators on the will not work. Once i switch the hot water to come on the system works fine until you want the rads off then you have to turn off the hot water. I have replaced the thermostat with no change to the problem. the only thing is how much should the valve open and close is it around 20 degrees because thats all mine turns with the motor i thought it should be more ? Please anyone got any ideas ? Thank you all in advance........

Reply to
Dirksdonuts
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I assume that you have a Y-Plan system - fully pumped, with a 3-port mid-position valve, designed to provide HW only, CH only, or both together? [See

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and scroll down to Y-Plan]

I assume from the fact that it has been playing up for a few days that it

*did* work properly prior to that? This is important, because there are lots of ways to wire up Y-Plan systems wrongly, and only one way to do it right!

Assuming it *has* worked ok in the past, you almost certainly have a problem with the 3-port valve - or more likely with its actuator. The valve is supposed to turn through 90 degrees between HW and CH - with the "both" position being mid-way at 45 degrees. The manual lever only moves the valve to the mid-way position.

It sounds to me that the motor is only moving it to the mid-way position when it should be moving it all the way to CH. This would explain why the boiler and pump only run when the HW is also on - because the valve never gets far enough open to operate the microswitch which provides an alternative supply for the boiler and pump.

I would recommend replacing the actuator - making a careful note of the wiring before disconnecting the old one, and connecting the new one

*exactly* the same. [You *can* buy the internal bits (synchro motors, micro-switches, etc.) and effect a repair - but it's a bit fiddly, and safer - in my view - to replace the whole thing].
Reply to
Set Square

Thanks for the fast reply setsquare it looks like i will be off to find a new actuator first thing in the morning.

Reply to
dirksdonuts

Thanks for the fast reply set square it looks like i will be off to find a new actuator first thing in the morning.

Reply to
dirksdonuts

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