Heating Wiring Problem - cylinder thermostat not working

[Aaron b]

If you look at the side of the valves there's a manual override. When it's energised you will see it move. You can force it on by pushing it to the open position and holding it up while it tries to close on the spring.

If they are both operating as expected mechanically and you are getting voltage on the orange with the valve in the closed position you have a faulty auxiliary switch which might have been what the electrician was referring to.

 

[davesparks]

one like this?

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No, I wouldn't trust that anywhere near mains voltages.

 

[dfreitag]

I would remove the permanent live from the valves by disconnecting the orange from the top of 11 and move it to the spare of 5. The spare black looks like it goes to the boiler. I'd connect that to 5 in the junction box and connect the black to 3 in the boiler.

Thanks for the instructions!

Just to make sure I don't misunderstand please see photos below - can you please confirm?

Many thanks!

 

[dfreitag]

If you look at the side of the valves there's a manual override. When it's energised you will see it move. You can force it on by pushing it to the open position and holding it up while it tries to close on the spring.

If they are both operating as expected mechanically and you are getting voltage on the orange with the valve in the closed position you have a faulty auxiliary switch which might have been what the electrician was referring to.

Hmm
Apologies, but I don't seem to quite understand what to do..


First of all, have I understood the below correctly?

HW&Heating OFF > ZV are energised & therefore closed

HW&Heating ON > ZV are "loose" & therefore open


Should I manually open them while the HW&heating is OFF? And what should I do then?


Quick reminder

• I was getting Voltage when HW&Heating is OFF (BEFORE changing the cables up according to your latest advice)
• I've confirmed that when HW&Heating is ON that the pipes heat up next to both ZV - does this mean they work correctly?
  [*]Upon the advice from the sparky I had over, I recently had the HW ZV changed (though only the motor, no the pipe).
  

Sorry for the "barrage"..

Many thanks again!

 

[brianmoooore]

In its rest position, a zone valve does not allow water to flow through it.
Applying 230V across the blue and brown wires opens the valve, so that water can flow, and also closes a switch between the orange and grey wires.
There is no electrical connection between the brown/blue wires and the orange/grey wires.
The power to the brown and blue wires should be controlled by the heating control system - thermostats, programmer, Nest, etc.
The boiler and pump should be controlled solely by the orange and grey wires, with no direct connection to the afore mentioned control system.
The boiler may also have a permanent live feed, which it uses to power the pump for a short while after the boiler has shut down, to prevent local overheating in the boiler.

 

[Aaron b]

Just to make sure I don't misunderstand please see photos below - can you please confirm?

Yeah that's what I was proposing. You would be removing the switch from the permanent live in the junction box and using the one in the boiler instead.

 

[dfreitag]

In its rest position, a zone valve does not allow water to flow through it.
Applying 230V across the blue and brown wires opens the valve, so that water can flow, and also closes a switch between the orange and grey wires.
There is no electrical connection between the brown/blue wires and the orange/grey wires.
The power to the brown and blue wires should be controlled by the heating control system - thermostats, programmer, Nest, etc.
The boiler and pump should be controlled solely by the orange and grey wires, with no direct connection to the afore mentioned control system.
The boiler may also have a permanent live feed, which it uses to power the pump for a short while after the boiler has shut down, to prevent local overheating in the boiler.

Thank you for clarifying, Brian!!

So I had it all wrong!

 

[dfreitag]

OK, so

I followed Aaron's instructions - and the boiler still fires up immediately - with HW&heat OFF.

Then I check voltage to ZV's again

with HW&heat OFF > 244V

with HW&heat ON > 0V


Is it me, or should it be the other way around??

 

[kropaske]

Before you go any further with this make sure you have the legionella prevention switched off in Nest settings as having this activated even with HW an CH in off boiler can kick in

 

[dfreitag]

Before you go any further with this make sure you have the legionella prevention switched off in Nest settings as having this activated even with HW an CH in off boiler can kick in

thanks for the heads up
I switched this off about a month back, when on the phone with Google..