No heating when water hot

ChrisR · 13 Sep 2005

The pump should be wired to the boiler, so the boiler puts the pump on whenever it's on itself, and for a while afterwards for cooling. So if boiler on and pump not on, pcb faulty.

WHat's on the grey wires, they should both be connected to Live.
The two orange wires from the 2 2 port valves will be connected together, so separate them and reconnect the CH one for tests. What's the voltage on the grey wire, which should be 230vac too. The grey and orange wires are only connected together by a simple switch when the valve is open - hard to see where 180v comes from unless there's a wiring error.

penno · 14 Sep 2005

Just had a quick probe oo er!

240v on the grey 180v on the orange, does this point to a duff microswitch?

ollski · 14 Sep 2005

If its only getting 180v at the boiler it won't switch to the pump as the pump is operated by a switched live form the boiler...sounds like the microswitches yes.

chrishutt · 14 Sep 2005

Could the 180v be the measurement you'd get if the DC from the mid position valve (the DC that stalls the motor in mid position) linking up to the orange wire?

ChrisR · 14 Sep 2005

Yes it would!
Half wave rectified mains would be about 180V!
There's a diode in a 3 port!

Trouble is, he's got 2 x 2 ports...

chrishutt · 14 Sep 2005

ChrisR said:
Trouble is, he's got 2 x 2 ports...

Ah yes, I forgot that. But isn't it a bit of a coincidence that he's getting 180v?

penno · 15 Sep 2005

Just finished this evenings instalment of find the fault, pretty sure its the microswitch now.

The CH 2 Way motors as advertised.

With Orange and Grey for the CH 2 Way disconnected it reads high resistance across the switch in either position.

The CH is working when the HW is on at the same time because the valve has motored open and water can get round the system.

If you turn HW off on the programmer but leave CH on nothing happens, but if you short 240 across the microswitch the CH system seems to work as advertised.

Presume the microswitch contacts are welded shut and dropping the voltage?

Seems logical to me and I will hopefully replace the top of the valve at the weekend.

Thanks for your advice to date

penno · 16 Sep 2005

Just replaced the electrical bit of the 2 port and the CH now works a treat.

ChrisR · 16 Sep 2005

Glad it works, but the 180v is a bit mysterious

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No heating when water hot

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