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Difference between mid point valve and diverter


JohnMo

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Dumb question

Looking for a 3 port diverter valve, to move flow from heating to DHW cylinder heating, not both at the same time. Everywhere I look a mid point valve comes up.

 

What's the difference is just wiring or are they completely different things?

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COMPLETELY different.

 

What you are wanting is a 2 way valve,  When energised, it switches to one port, when not energised it switches to the other.  Nice and simple and reliable.

 

A 3 port 3 way valve is the work of the devil, something dreamed up by a boffin trying to do something as cheap as possible.  It has a complex switching system that can stall the motor (with DC) at mid point to send water to both ports.  You might gather I hate them and would never have one in my house.

 

If you can't find a 3 port 2 way valve I would plumb it instead with individual 2 port valves.

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So just 2 x 2 port valves and use the power from heat pump to energise a change over relay.  Power one relay to to have flow through heating, power relay from heat pump, power moves from one 2 port valve to the other, opens 2 port to cylinder?

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11 minutes ago, JohnMo said:

So just 2 x 2 port valves and use the power from heat pump to energise a change over relay.  Power one relay to to have flow through heating, power relay from heat pump, power moves from one 2 port valve to the other, opens 2 port to cylinder?

Does the heat pump not have separate outputs for hot water and heating?

 

If you really can't find a 3 port 2 way valve, you can get one normally open and one normally closed 2 port to work from one output.

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2 hours ago, JohnMo said:

What's the difference is just wiring or are they completely different things?


And yes - wiring is usually 5 wire with LNE to the valve motor and a SPST micro switch that is NC when the valve is energised

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