Constant call for heat from cylinder thermostat?

[jamojamo]

Sorry should have said to lowest setting rather than zero, it looks like that would be 15.

 

[gazfen]

Hw on and hw off are mixed up, try switching them. Or 1 and 2 on the cylinder stat.

 

[DP]

Hw on and hw off are mixed up, try switching them. Or 1 and 2 on the cylinder stat.

Hence my suggestion that CH be tried with HW on.
In this case HW selection will not start the boiler but CH will

 

[DP]

Sorry should have said to lowest setting rather than zero, it looks like that would be 15.

Any progress on this one?

 

[jamojamo]

I've been looking at the hive wiring today, as a suggestion was to bypass it as a mean to see where that was the issue.

This is what I'm looking at right now, which wasn't quite what I was expecting....

 

[RandomGrinch]

If you put the brown wire from L into terminal 1 (on the Hive backplate, ensuring power is isolated beforehand), the boiler shouldn't call for heat for hot water (when the circuit is re-energised).
If you then move the brown wire to terminal 3, the boiler should start up for hot water.
If this works correctly, it is likely to be the Hive at fault.
If hot water is called for, with brown in terminal 1, the problem lies elsewhere.

 

[jamojamo]

RandomGrinch..

First thanks again for trying to help with this.

I first followed one of your other suggestions and tried the system with the hive removed from the backplate.

Odd things occured...lol let's see if I can explain.

With hive removed, and boiler fired up, it shows me the temp in display, makes some noise (no flame icon) and then after a min or so gives me an FD fault (no flow).

Now with hive back on backplate it did the same, until I tried pressing HW on the hive and then it fired up and you could hear water rushing in (it activated the pump too).

 

[jamojamo]

Also before I swap wires around, does my hive wiring look normal to you, terminal one threw me.

 

[RandomGrinch]

Also before I swap wires around, does my hive wiring look normal to you, terminal one threw me.

Yes, the wiring will likely be 'ok' - until fairly recently, it was allowable (but not good practice) for a green/yellow wire to be used as a switched live, if it was oversleeved.

With hive removed, and boiler fired up, it shows me the temp in display, makes some noise (no flame icon) and then after a min or so gives me an FD fault (no flow).

I don't know what others may think, but to me, this suggests that the Hive may be working.
With the hive removed, the only way a switched live would be received at the boiler would be via a faulty/miswired 3 port valve or tank stat (or possibly, even a faulty boiler PCB).

Do you have a separate wiring centre?

Edit: with the Hive removed from the backplate, does turning the tank thermostat down, still stop the call for heat?

 

[jamojamo]

Ok re wiring check. It was done about 18 months ago.

To clarify, before when boiler turned on it was immediately heating (flame icon) hot water. Pressing boost on water or heating on hive didn't do anything. Pump running.

All I've done is take the hive off the backplate and now put it back on.

Now when I turn on boiler the pump doesn't kick in, the boiler seems to try but doesn't heat (no flame icon) then FD fault. (Because pump not active as it was before I removed?) I press water boost and pump kicks in and boiler heats (flame icon).

Yes, there are lots of parts and wiring on this system, I'll post some pics up for you to look at, the main wiring center I have never touched. There also some sort of frost monitor thing outside. 2nd pic is 3 way.

 

[jamojamo]

Worth saying that when I turn water boost off now, the pump stops, the boiler continues then FD fault.

 

[jamojamo]

As in the temperature display continues to rise quickly (as the pump has gone off) then FD fault.

 

[jamojamo]

Have a watch....

 

[jamojamo]

As regards your edit question (just seen it), unlike before where turning tank stat down stopped pump and boiler. Now it stops pump the flame goes off on boiler but the temp display keeps rising.

Did/re connecting the hive has deffo changed something, if not for the better.

 

[DP]

As in the temperature display continues to rise quickly (as the pump has gone off) then FD fault.

Wiring issue right away.
Boiler and pump feed from controls.
Look at the manual. Assume nothing.
In some cases a pump over run kit may be needed which Ideal make.
That green used as HW off is bad practice

I would rip all the wiring out and start again.
Hive seems to be a go to programmer. There are loads others that make life much much easier and have enhanced features too