central heating should "HW Off" be permanently live?
- Thread starter pedro1234
- Start date
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HW off comes from two places. When either the hot water is 'off' at the programmer (ie switched off manually, or by the timer function) or, when the hot water cylinder thermostat is at 'satisfied' The rest of the time it should not be live.
Why are you testing it, is something not working.
Why are you testing it, is something not working.
The valve when at rest, sits in the hot water only position, when heating is required, the valve winds across and opens the heating port, so it is unusual for the motorised valve to fail like this, normally when they fail the heating doesn't come on at all. It's possible that the valve has stuck or seized so that the heating port is slightly open, or some debris is preventing it closing properly.
With the main electrical supply to the heating switched off (not just switched off at the programmer) so that the valve is at the 'rest' position, can you move the lever at the side of the valve from the 'auto' to 'manual' position and can you feel any resistance when you do?
Has the system been working OK and the fault only recently become manifest?
Has anything to do with the heating system been changed / replaced or modified recently?
With the main electrical supply to the heating switched off (not just switched off at the programmer) so that the valve is at the 'rest' position, can you move the lever at the side of the valve from the 'auto' to 'manual' position and can you feel any resistance when you do?
Has the system been working OK and the fault only recently become manifest?
Has anything to do with the heating system been changed / replaced or modified recently?
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The lever moves freely with no resistence.
Boiler replaced approx 6 weeks ago and system drained down to fit a drain tap to the CH system and recharged approx 2 weeks ago.
I believe the system worked ok untill a couple of days ago when I noticed the rads on when they should not have been.
Boiler replaced approx 6 weeks ago and system drained down to fit a drain tap to the CH system and recharged approx 2 weeks ago.
I believe the system worked ok untill a couple of days ago when I noticed the rads on when they should not have been.
If the lever moves freely, then the valve is already in the heating position, and it shouldn't be there when the power is turned off. [The reason for turning off the power and not just switching it off at the programmer is because the valve can still be powered even when the programmer is set 'off']
When there is no power applied to the valve, an internal spring should pull the mechanism so that it closes off the heating port, and you would feel resistance when you moved the lever.
Sounds like it's time for a new valve.
When there is no power applied to the valve, an internal spring should pull the mechanism so that it closes off the heating port, and you would feel resistance when you moved the lever.
Sounds like it's time for a new valve.
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