Difference between mid point valve and diverter

[JohnMo]

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?

[ProDave]

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.

[JohnMo]

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?

[ProDave]

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.

[billt]

I've just bought one of these https://directheatingsupplies.co.uk/products/honeywell-v4044c-1569-3-port-valve-28mm?_pos=2&_sid=02d795d3f&_ss=r

 

You can use a mid position valve as a diverter, connect the white and grey wires to the switched output and don't connect the orange wire. That's what I did on my CH system.

[PeterW]

You need to search for a Diverter Valve

 

https://www.draytoncontrols.co.uk/products/motorised-valves/3-port-diverter/motorised-valve-3-port-diverter

 

 

[PeterW]

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