When I set my controls for heating only this works, when I set my controls for hotwater only this works, when I set my controls for central heating and hotwater only the heating works. Does this sound like a fauly three port valve?
Three port valve problem?
- Thread starter carlsbergy
- Start date
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First suspect is the WIRING! A huge proportion of 3 port valves aren't wired correctly.
Even having the wiring diagram etched into your psyche it can still take quite a while to sort out what's been done, especially if the "junction box" looks more like a box of worms.
Start here:
http://content.honeywell.com/uk/homes/Catalogue/Sundial Plans/3.4 Y Plan.pdf
The wires most likely to be wrong or missing are the HW OFF, or "satisfied" wires from the cylinder stat and the programmer.
If all looks to be in order, the micrswitches in the head can go faulty.
Even having the wiring diagram etched into your psyche it can still take quite a while to sort out what's been done, especially if the "junction box" looks more like a box of worms.
Start here:
http://content.honeywell.com/uk/homes/Catalogue/Sundial Plans/3.4 Y Plan.pdf
The wires most likely to be wrong or missing are the HW OFF, or "satisfied" wires from the cylinder stat and the programmer.
If all looks to be in order, the micrswitches in the head can go faulty.
check tank stat to check water is not satisfied also check valve is the right way round
not all valves are mid position and some will prioritize hot water (valve could be wrong way round)
not all valves are mid position and some will prioritize hot water (valve could be wrong way round)
Thanks for replies, sorry I should have mentioned it has been working fine up to now.
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When you select HW only or CH only, that is exactly what you get!
When you select HW and CH together you only get them both until one of them has been satisfied. Your HW is not losing heat to the same extent as CH which is losing heat through radiators at a steady rate.
So even though you select HW/CH the valve spends most of its time in the CH only position and may go back to HW/CH occasionly.
So maybe you don't have a problem.
Also note that when the CH is satisied, the room stat cuts off the power supply to the boiler, but it does not affect the position of the valve.
For the valve to move from CH only there has to be a demand for HW.
Unless of course you cut off the power supply to the programmer and the return spring will then act on the valve and send it back to the rest position ie HW.
When you select HW and CH together you only get them both until one of them has been satisfied. Your HW is not losing heat to the same extent as CH which is losing heat through radiators at a steady rate.
So even though you select HW/CH the valve spends most of its time in the CH only position and may go back to HW/CH occasionly.
So maybe you don't have a problem.
Also note that when the CH is satisied, the room stat cuts off the power supply to the boiler, but it does not affect the position of the valve.
For the valve to move from CH only there has to be a demand for HW.
Unless of course you cut off the power supply to the programmer and the return spring will then act on the valve and send it back to the rest position ie HW.
Thanks for replies, which I can now go through to sort out.
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