Air source heat pump heating issue

[Themorganator4]

Junction box,

The one on the wall next to the switches.

You'll probably find a multi core flex going from there to the HP.

One core will go to terminal 9 on the HP and the heating MV should be connected here also.

I'm not sure what the three port is doing, especially in the position it is. Might be a return diverted.

Any joy with the engineers manual?

I won't be able to get round to that until the weekend, as soon as I do I will post the results

 

[Wilko]

Hi - this is a 2 pole voltage tester and I wouldn't attempt this without it, or its brother. I'm just repeating I know, but inside the valve covers are L conductors and if the place has been installed incorrectly they may not isolate with the local switch. That's why we test everything to everything.
Megger TPT320 AC/DC Voltage Tester - https://www.test-meter.co.uk/megger-tpt320-ac-dc-voltage-tester/

 

[Themorganator4]

So you're saying they could still be live even if isolated due to poor wiring?
Also what is the purpose of a 2 pole tester?

 

[Themorganator4]

So it appears that terminal 9 is reading 240 regardless if heat is on or off, what does this mean?

 

[Themorganator4]

And I assume I put 1 probe on the live wire and the other on terminal 9? Sorry I am a bit of a noob unless the electrics are very basic

 

[GBDamo]

And I assume I put 1 probe on the live wire and the other on terminal 9? Sorry I am a bit of a noob unless the electrics are very basic

T9 should be a live feed to the heating MV, if I read the diagram correctly.

It should be live in heating only.

Test between T9 and a common neutral not a live.

Let me know how you get on.

 

[GBDamo]

T9 should be a live feed to the heating MV, if I read the diagram correctly.

It should be live in heating only.

Test between T9 and a common neutral not a live.

Let me know how you get on.

Just looked at the wiring diagram in full screen, the heating MV could be being fed from other places further up the terminals.

Could yo post a picture of this from inside the heat pump.

 

[Themorganator4]

 

[Themorganator4]

Tried testing with 1 pin in the N and the other at T9, no voltage when heating off or on

 

[Themorganator4]

On another note i loosened the switch which was stuck in manual on the MV, it's in auto but it's made no difference

 

[Themorganator4]

Just looked at the wiring diagram in full screen, the heating MV could be being fed from other places further up the terminals.

Could yo post a picture of this from inside the heat pump.

Any ideas

 

[Themorganator4]

Bump

 

[Wilko]

Hi - I think it's likely there is a control fault. IIRC the heat pump runs but has never been controlled properly for you (?). If so, it's possible the fault could be an incorrect control design (one that could never work), or an incorrect installation (defeating an appropriate design), or a more recent failure of valves, micro switches or conductors. There may also be an internal fault with the heat pump unit. Each of these needs eliminating and I think you are going to need onsite help with this.
PM me if you want.

 

[Themorganator4]

Yes, the heating works whilst the hot water is on but doesnt work on its own accord. All the valves open etc as they should so in order to have heating, I have to turn on the hot water and the pump heats up both, problem is the heat pump turns off when the hot water is up to temp even if the room is freezing. If I just turn on heating, all valves etc work but the heat pump is off.

 

[solarsavings]

The programmer you have, is it a Honeywell ST9400c ?