Fixing Y Plan/Honeywell V4073A design flaw

[TomaszG]

Hello all,
The Y plan with the Honeywell V4073A Mid position valve has a small design flaw, where the valve motor can stay continuously powered up when it doesn't need to. It happens when the CH was the last demanded position (according to my knowledge). I know that the motor is design to endure such conditions, but I think that it has an impact on the longevity of the motor and the whole valve plus it does use a 6W!!! of energy. These facts caused my brain to involuntarily, especially before falling asleep, start looking for a solution. One of possible solutions, which came in to my mind is to use NO relay controlled by the White cable (Heating on) and disconnecting the Grey cable (Hot water off), so when there is no demand for heating the motor will be unpowered and the valve will return to B position (HW only) with the use of spring. Would that make sense and would that work?

 

[Roddy Young]

I totally agree that this is a poor design. In my last house the motor burnt out after only 7 years which wasn't a great surprise. Any time I touched the motor it was energised and very hot. It sat on a hot pipe which added to the problem.
At that time, c1995, the Honeywell motors were difficult to source and expensive at over £25.
So I rewired through a relay like you are thinking (though I now can't remember exactly how I did it...old age...).
I never had another burnt out motor in the following 13 years.
Roddy

 

[Johntheo5]

This way??.

 

[TomaszG]

This way??.

Yes, exactly.

 

[oilhead]

Many modern programmers will switch off the power when programmed to off.