Honeywell Power Head very hot
- Thread starter MysticMartin
- Start date
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I don't see why it wouldn't work. If I turn off the programmer at the mains the valve returns to rest. I then turn the power back on, grey is still powered but the valve remains in rest.
Martin
Based on your questions I did a little test on a genuine Honeywell motor valve.
When turning it took 38 mA which is 9.1 W
When stalled it took 8 mA which is 1.9 W
But different valves use different makes of motor and there is always the possibility of shorted turns on the motor which could increase the consumption.
In my test case it is surprising that just 2 W can make the valve so hot.
Also the current is partly inductive so the actual consumption could be somewhat less.
Tony
When turning it took 38 mA which is 9.1 W
When stalled it took 8 mA which is 1.9 W
But different valves use different makes of motor and there is always the possibility of shorted turns on the motor which could increase the consumption.
In my test case it is surprising that just 2 W can make the valve so hot.
Also the current is partly inductive so the actual consumption could be somewhat less.
Tony
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All you need to do is remove the voltage from the grey wire for a few seconds. Turn HW ON, count to 5, turn HW OFF.
However, I wouldn't bother about it; the valves are designed to work like this. The bright steel covers are probably made like that to dissipate the heat.
In any case, it's not just overnight that the valve is held in the CH position: it's virtually all the time. In fact the only time the valve is not held in the CH position is when the valve is in the HW position or in mid-position.
For example:
HW and CH turned on in the morning (valve mid-position)
HW satisfied (valve moves to CH position)
CH stat satisfied (valve stays CH pos)
CH stat calls for heat (Valve already in CH position)
and so it continues until there is another call for HW.
However, I wouldn't bother about it; the valves are designed to work like this. The bright steel covers are probably made like that to dissipate the heat.
In any case, it's not just overnight that the valve is held in the CH position: it's virtually all the time. In fact the only time the valve is not held in the CH position is when the valve is in the HW position or in mid-position.
For example:
HW and CH turned on in the morning (valve mid-position)
HW satisfied (valve moves to CH position)
CH stat satisfied (valve stays CH pos)
CH stat calls for heat (Valve already in CH position)
and so it continues until there is another call for HW.
I now know I'm making a fuss unnecessarily as it is meant to work this way.
However I do like the idea I can power it down when not in use. My heating and water both go on in the evening only, so most of the day it isn't being used and could be resting (yep - the hot water does last that long and the thermostat is at 50C). So having a push switch that will remove power from the grey wire for a few seconds (whilst leaving the programmer with power so it doesn't risk losing its memory) is a nice-to-have.
I think I'll give it a go.
Martin
However I do like the idea I can power it down when not in use. My heating and water both go on in the evening only, so most of the day it isn't being used and could be resting (yep - the hot water does last that long and the thermostat is at 50C). So having a push switch that will remove power from the grey wire for a few seconds (whilst leaving the programmer with power so it doesn't risk losing its memory) is a nice-to-have.
I think I'll give it a go.
Martin
That won't work every time. If you turn the HW 'on' and the cylinder thermostat is satisfied, that will keep the live on the grey wire.
The programmer has a flash memory that saves the program settings without power.
If the backup battery is not adequate all it loses is the time.
So turning off at the supply will do what you want although its a total waste of time in my view!
I still don't know why you are so bothered. A consumption of 2 W costs just 21p each year, hardly anything to get very excited about!
Tony
If the backup battery is not adequate all it loses is the time.
So turning off at the supply will do what you want although its a total waste of time in my view!
I still don't know why you are so bothered. A consumption of 2 W costs just 21p each year, hardly anything to get very excited about!
Tony
Also, on the plus side in the summer when only hot water is being used, unlike a two port S-Plan, it won't use any power whatsoever as it will sit at at rest in the hot water only position all of the time.
I know, it's true, I'm being pedantic. It's the way it feels so hot to touch when off that it appears very wasteful but in reality it's pretty insignificant.
Thanks for everyone's input. It's been a useful learning experience.
Martin
Thanks for everyone's input. It's been a useful learning experience.
Martin
There will always be voltage on the grey wire after HW has been turned off by timer or stat. It just needs to be interrupted so the spring starts moving the valve back to the HW position. This causes one of the switches in the valve to flick over, so the voltage from the grey wire is no longer applied to the motor.
Maybe you don't need to count to 5, just turn HW ON and back OFF.
See V4073A Operation, last para.
It would only be interrupted for milliseconds as the programmer's changeover contact switches from being directly connected to the grey wire, to being connected to the grey wire via the thermostat. I doubt that this would give enough time for the motor to move sufficiently.
It would need to be interrupted for a couple of seconds as they can take that long to return.
But all totally irrelevant to save just 21p a year and spend a couple of hours doing it each year too.
Better to leave it alone just as it does in 99.9999 of other installations.
Tony
But all totally irrelevant to save just 21p a year and spend a couple of hours doing it each year too.
Better to leave it alone just as it does in 99.9999 of other installations.
Tony
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