Lifestyle LP241 replaced with Hive CH issue

[ericmark]

OK managed to measure voltages (All AC voltages) this evening

HW + CW Both on (Boiler On). Orange = 240V, White = 240V, Grey = 0V

HW Only On. (Boiler On) Orange = 240V, White = 28V, Grey = 0V

CH Only On (Boiler off??). Orange = 0V, White = 240V, Grey = 15V

As said, CH only grey should be 230 volts, the valve

is an odd device, and it can result in some odd voltages. @stem has shown how it is wired, and the boiler is run direct from the tank thermostat when set to DHW or DHW plus CH, and the 230 volts at the orange is actually a back feed from the boiler.

So if SW2 is faulty, then you will not get CH on its own.

 

[stem]

So if SW2 is faulty, then you will not get CH on its own.

This is correct, but without a live on the grey wire, SW2 will never operate, and that's what we're missing.

 

[LordWhiteley]

Well luckily I do have a spare Drayton MA1 3 position valve I can swap over...

 

[stem]

With a new valve, you will still need to fix the HW off signal to its grey wire, without it, it will not move to CH only.

 

[LordWhiteley]

Yes I missed that point . I'll try an measure the HW off, HW on & CH on the terminals on the back of the Hive control unit. If they match those measured on the 3-valve, in particular grey HW off - then the Hive unit is suspect - I also verify this by refitting the LP241 and seeing if CH on works again as it used to.

 

[ericmark]

I also realised there is a problem with the backplate, once the hub is removed to get access to the contacts, clearly you can't test if the unit is switching, lucky I have a wiring centre between the hubs, allowing me to measure.

So assuming two channels, I would fit links if you then get CH you know the wiring to backplate is OK.

 

[LordWhiteley]

OK I did two things today. (1) I swapped over the LP241 but it still did the same thing ie CH On - only when HW on at the same time. (2) The second thing I did was measure the AC voltages on the terminal block at the back of the HIVE unit while connected :-

 

[denso13]

Did you do this?

The easiest way would be to check for 240v on Hive terminal 1 with the HW set to off. Remove the wire that is currently in the terminal for the duration of the test to prevent any unwanted voltage coming from it.

 

[LordWhiteley]

Did you do this?

I could try that next. So remove the wire from Terminal 1 and then measure the voltage on the Hive terminal?

 

[denso13]

I could try that next. So remove the wire from Terminal 1 and then measure the voltage on the Hive terminal?

Start from there and work towards the fault.

 

[LordWhiteley]

Here are the measurements of on Terminal 1 (Wire removed) :-

 

[denso13]

So that seems to show that you are getting 240v on terminal 1, on line (2), which is correct. Test it now in the wiring centre, you said previously the grey was 0v. Looks like the Hive is ok.

Hope I'm understanding all of your readings ok...

 

[LordWhiteley]

So that seems to show that you are getting 240v on terminal 1, on line (2), which is correct. Test it now in the wiring centre, you said previously the grey was 0v. Looks like the Hive is ok.

Hope I'm understanding all of your readings ok...

So do I I will double check the 3-way valve voltages and add to the table

 

[LordWhiteley]

Here they are -

 

[denso13]

CH Only On (Boiler off??). Orange = 0V, White = 240V, Grey = 15V

You seem to be getting different results now, as above you weren't getting 240v on the grey, now you are? Is it working now, the values are as expected with CH only on?