How do I wire up my Heatmiser Thermostat?

[freshy]

Hi,

I'm trying to fit my new Heatmiser Thermostat and am a little confused as to why it's not working... I'm simply not getting any power on the digital thermostat!?

Please can someone tell me if I have wired it up correctly.

The wires that are availble from my old honeywell thermostat are as below;

Red
Blue
Yellow
& Earth (conected to metal backbox)

The Heatmiser DT has 4 connections

L
N
A1
A2

I have wired up thermostat as below

L - Red
N - Blue
A1 - Yellow
A2 - Red (split from L)

Thanks

Freshy

 

[bathjobby]

I have one of these and it appears you have it wired correctly. Have you got a meter to check the 230v at the DT ? If you have mains at the DT, you have switched it on ? If you don't have mains at the DT have you got your programmer to have CH on ? Its the programmer that switches power on to your Thermostat. In order to let the DT programmes run as you want them you have to have you CH set to on/24hrs at your programmer so that the DT is always powered.

 

[fasea]

I have one too. I would check the voltage on the live feed to ensure its getting 240volts and if it is I would then check you have the ribbon cable correctly connected.

I have no idea on your old thermostat but I presume your boiler uses a 240V circuit for the thermostat rather than 12V that some do ... ?

Cheers

Andy

 

[bathjobby]

Before I started installing mine (removing old one etc), to guard against just such a problem that freshy is having, I bench tested it.
Freshy, if none of the suggested so far helps you, email or phone Heatmiser. I had a few questions for them and they were really on the ball with the speed and content of their email replies. I also noticed a few pixels on the clock were out and they dispatched a replacement immediately (without waiting for returned DT) and more than compensated me for postage. All in all, great customer service.
N.B. There is a function on these units not documented; You can adjust the current temp during any program cycle. It adjusts just for the current program cycle and doesn't change the programed temp. Handy for eg if your staying up late and your colder overnight prog kicks in.
Pressing either of the up / down temp keys once displays the SET temp, then continue to use these keys to set the temp you temporarily want, then press the 'A' key to set it for this cycle without affecting the programmed temp.

 

[stevesey]

N.B. There is a function on these units not documented; You can adjust the current temp during any program cycle. It adjusts just for the current program cycle and doesn't change the programed temp. Handy for eg if your staying up late and your colder overnight prog kicks in.
Pressing either of the up / down temp keys once displays the SET temp, then continue to use these keys to set the temp you temporarily want, then press the 'A' key to set it for this cycle without affecting the programmed temp.

It's in the newer manuals (got mine 4 weeks ago).

 

[croydoncorgi]

The idea of the Live & Neutral connections to the Heatmiser are that there is a permanent Live supply to operate the thing.
This is NOT the same as the Red ('Sometimes-Live') and Yellow (Live Return) on the Honeywell box.
My guess would be that the Red wire is only going to be live when an existing Programmer that you've left connected is calling for heat (ie. in a timed-on period). You say you 'split' the Red wire from Live. Where? Why?

The quickest way to fix this is to select CH permanently On at the programmer and then wire the Heatmiser EXACTLY as shown on your diagram, so that Red puts live on L and A2 and the boiler gets its Switched-Live from the A1 terminal on the Heatmiser via the Yellow wire. Check that the wires are correctly-connected at the other ends too!!

 

[freshy]

Hi,

Thanks for all your suggestions...

I ended up calling Heatmiser on their support line and they were very helpful although they could not fix the problem.

After buying a new multi-meter I discovered that the neutral was not giving me 240v. Even with the CH & HW both on 24hrs.

I traced the wires back to a junction box in my boiler room and still nothing on the neutral. Therefore I can only assume that my the old honeywell does not require neutral to work!

However the heatmiser requires the neutral to work! The neutral from the Programmer does not have the 240v I require either...

There are two other blue wires connected to the black wire from the programmer which has 240v.

Does anyone know where I should connect the neutral from the thermostat to make it work?

Thanks

Freshy