Danfoss RET2001M no display when not in use

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I have the above room stat but it doesn't show anything on the digital screen until the programmer tells the boiler to turn on.

Is this meant to have a live feed for display power all the time?

It's a Drayton L711 1 channel programmer is it makes any difference

 

[stem]

The RET M is available in various models, as per the table below.

As you can see, it comes in mains and battery versions. The RET2001M you have is shown as being mains operated.

Ideally where the thermostat gets its 230V mains supply via a programmer, which does not provide it with a permanent live supply, a battery operated version would usually be chosen so that the display is maintained.

Having said that, mains versions of the RET M as below have separate terminals for the heating control via the programmer (terminals 2 & 4) as well as provision for a separate and permanent 230V mains supply (terminals N and L) which provides power to the electronics even when the programmer has switched the heating off.

I'm guessing that yours hasn't been wired with a dedicated 230V permanent supply, but instead takes it via the programmer meaning the thermostat has no power when the programmer switches off.

It should be possible to provide the thermostat with a permanent 230V supply to maintain the display, but it will probably require the installation of a new cable and the permanent mains supply should come from the same 3A fused connection as the rest of the heating system.

 

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this is the back of the programmer

 

[stem]

No issues with the programmer, that's all as it should be.

At the thermostat the brown wire link wire between L and COM shows that the control circuit and mains supply are using the same switched supply from the programmer.

To wire it properly:

1. Thermostat link between L and COM would be removed

2. The brown wire in thermostat L is moved to COM

3. A new connection is made between the now vacant thermostat L and a permanent live associated with the heating system. The L at the programmer would do.

 

[screamer]

No issues with the programmer, that's all as it should be.

At the thermostat the brown wire link wire between L and COM shows that the control circuit and mains supply are using the same switched supply from the programmer.

View attachment 328616

To wire it properly:

1. Thermostat link between L and COM would be removed

2. The brown wire in thermostat L is moved to COM

3. A new connection is made between the now vacant thermostat L and a permanent live associated with the heating system. The L at the programmer would do.

Thanks for the detailed info.

As you say, it needs a permanent live between the stat and programmer which there isn't one there, I'd need to run another cable to add this?

 

[stem]

Looks like it. As far as I can see the existing cable only has 3 cores. Which is probably why it was installed like it has been.

 

[RandomGrinch]

...or alternatively, replace the thermostat (or programmer) with a combined smart thermostat/programmer?

The wiring would be relatively straightforward, all that would be needed, would be for one of the controls to be linked out (i.e. if you replaced the programmer with the smart stat, link out the thermostat).

There are plenty of single channel products that will simply clip onto your existing programmers backplate (Hive, Wiser, etc.)

This will allow you to change the temperature and timings from one place - after all, if you supply a permanent live to the RET2000M, no adjustment of the temperature will have any effect, unless the programmer is on (and there will be no useful indication to tell you that this is the case).

 

[screamer]

...or alternatively, replace the thermostat (or programmer) with a combined smart thermostat/programmer?

The wiring would be relatively straightforward, all that would be needed, would be for one of the controls to be linked out (i.e. if you replaced the programmer with the smart stat, link out the thermostat).

There are plenty of single channel products that will simply clip onto your existing programmers backplate (Hive, Wiser, etc.)

This will allow you to change the temperature and timings from one place - after all, if you supply a permanent live to the RET2000M, no adjustment of the temperature will have any effect, unless the programmer is on (and there will be no useful indication to tell you that this is the case).

I have been looking at them, mainly Google Nest

I did ask WB if their boilers supported opentherm but they said they didn't. (not that i know much about opentherm)

My boiler is a 37CDi (13 years old)

 

[RandomGrinch]

I have been looking at them, mainly Google Nest

I did ask WB if their boilers supported opentherm but they said they didn't. (not that i know much about opentherm)

Much of it depends on what you want to achieve.

If you are after the minimum of wiring modification; you would use your existing backplate, slot on a Single channel Hive, Wiser, or some other Drayton's and simply link out your existing stat.

If you wanted something mounted on the wall, where your existing stat is; you could look at a wired Tado, and link out your programmer.

Equally, the Nest Heatlink could replace your existing programmer - your existing wiring could possibly be reused to provide power between the Heat link and Thermostat, but that would require further investigation - it's not obvious how the wiring links up from your photos.

I'm afraid I don't believe your boiler is compatible with Opentherm - you are stuck with on/off type stats.

 

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@stem

Cable fitted and working as it should be, cheers