Y plan ,mid position valve conundrum?

[steveboy]

Hi folks ,The problem i have is that when the programmed time as elasped on (CH)the (honeywell mid postion valve) stays in its last postion ,this causes it to get hot over night and i read somewhere that this isen`t good for them as over time it causes them to burn out in other words the valve is still energised.I have checked and double checked all the wiring and seem to have got all the wires from the thermostats in the correct configuration with the boiler ,programmer and valve. MY main question is this " Is it normal for these type of valves to stay in their last position or should they wind back to default position using its return spring when the programmed time as elapsed?
I have been pulling my hair out for over a year now over this problem ,its not so bad in the summer as only the DHW is called for and the valve doesn`t move but now its winter and both CH and or DHW is called for the problem is back!!!

many thanks and festive cheer
steveboy

 

[doitmyself]

MY main question is this " Is it normal for these type of valves to stay in their last position or should they wind back to default position using its return spring when the programmed time as elapsed?

It's working correctly. This set of diagrams show the various states of the valve. You will see that, when CH is satisfied, the motor is still receiving 240v through the grey wire. So the valve stays held in the CH only position. The motor only uses up 6W, but as it is in a very confined place the actuator soon gets hot.

 

[steveboy]

Ok, thanks for that ,i can see what is happening on the wiring diagram ,however will it harm the motor over time ? or is there a way to wire it so that when the programmed time as elasped no power will be drawn from the motor thus causing it to wind back to default position using its spring.

Many thanks
steve

 

[Bernie2]

The motors are synchronous Google "Synchronous motor" tells you a bit more about how they work. They are not like normal motors.

 

[doitmyself]

will it harm the motor over time ?

Motors are know to fail after several years, but they are under £20 and are easy to replace.

is there a way to wire it so that when the programmed time as elapsed no power will be drawn from the motor thus causing it to wind back to default position using its spring.

None of the valve manufacturers' have come up with a method, so I doubt if anyone else will. Sunvic make a valve which does not use a spring to return to default; it uses the motor. It's know as a MoMo (motor on, motor off) valve. The only problem is that it has a bad reputation for early failure.

 

[steveboy]

Ok guys, thanks for that info i`ll just have to live with it ,just as an after thought ,do the valves on the "S plan" system close off when the programmed time as elasped ?

 

[doitmyself]

Ok guys, thanks for that info i`ll just have to live with it ,just as an after thought ,do the valves on the "S plan" system close off when the programmed time as elasped ?

Yes. When the timer or thermostat turns the heating or hot water off, power is removed from the valve which then closes under spring control.

There is also the "W Plan", not used much, which has a 3-port diverter valve. This can only be in two positions - port A open or port B open; there is no mid-position. This means you can have heating or hot water but not both at the same time. This type of valve automatically reverts to default position when the power is removed.

 

[steveboy]

So the solution ,if someone could devise it, would be the "Yplan" system but wired somehow to operate like the "w plan"

cheers

Steve