mid position valve fault
- Thread starter catbumble
- Start date
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Find the terminal connected to the valve grey wire. There should be two more wires on the same terminal: one to the cylinder thermostat, the other to the Programmer HW OFF terminal. You may find that the last one is missing.
I think you'll have to explain what the problem is a bit clearer.
When the HW and CH are on together you say the heating will not turn.
Not sure what you mean.
When HW and CH are both on together the valve takes up the mid position but this only until either HW or CH is satisfied. If say HW becomes satisfied the cylinder stat diverts power to the grey of the valve and sends the valve to CH only.
In doing this the boiler stops due to the diversion, but lights up again because the triggering of a micro switch allows power to be restored, only it now comes from the valves orange wire whereas before it was from the cylinder stat.
Common problems are
(a) valve does not move to CH only position. or
(b) valve does move to CH only position but fails to light boiler
When the HW and CH are on together you say the heating will not turn.
Not sure what you mean.
When HW and CH are both on together the valve takes up the mid position but this only until either HW or CH is satisfied. If say HW becomes satisfied the cylinder stat diverts power to the grey of the valve and sends the valve to CH only.
In doing this the boiler stops due to the diversion, but lights up again because the triggering of a micro switch allows power to be restored, only it now comes from the valves orange wire whereas before it was from the cylinder stat.
Common problems are
(a) valve does not move to CH only position. or
(b) valve does move to CH only position but fails to light boiler
Check that your valve is a 3 port mid position
valve.
It may well be a 3 port diverter valve with hot
water priority. In which case the heating will not
come on until the hot water is satisfied.
If it is a Honeywell valve what is the model number
printed on the end?
valve.
It may well be a 3 port diverter valve with hot
water priority. In which case the heating will not
come on until the hot water is satisfied.
If it is a Honeywell valve what is the model number
printed on the end?
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If it is a diverter as opposed to a mid pos it will have only 3 wires instead of 5.
Make and Model of Valve? Sunvic valves are notorious for this!
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