Horstmann two-channel ASR2-RF boiler control unit

Has anyone had any experience with these? Good or Bad?

I want to replace my existing (non z wave) controller for the hot water and heating. My worry is that making it z-wave could over-complicate things. I want to be able to switch heating on and off without worrying about my network crashing or batteries dying or anything else.

My central heating system is an old unvented system with a pump and a divertor valve. Will this control those too? I assume the pump gets triggered only when the heating is on?

Sorry if these are dumb questions. I don’t know much about how the central heating system gets controlled.

I can only answer parts of your question. I am using this to control my boiler and hot water. I have replaced the main (and only) thermostat in the house, and the 2 channel receiver replaced the one I had near my hot water cylinder. The swap over was easy, took about 30 minutes for both. Setting up in Vera is fairly easy too. You end up with a system which can work just as your old one did, your heating is simply controlled by the thermostat. If you go for the controller without the timer, you set timing for your hot water with a schedule in Vera. Next, you either use schedules, or preferably PLEG to write something to set your heating the way you want it. So you can have schedules, manual override, remote controllability etc. The system works very reliably. The thermostat send battery information to Vera, so you have enough warning to change the batteries before it dies. Even if it does, you just pop in 2 new batteries (I use rechargeable batteries). The 2 channel controller is mains powered, so no worries there, and if all fails, you have a manual override on the 2 channel as well. I only need that once when my Vera died. It was not very convenient to use, but it was only a few days until I got my Vera replacement.
Hope that helps

Hi my current heating system is similar to yours I assume you currently have an external programmer for the boiler some where and a thermostat. I did, so the two channel ASR-RF control unit replaces the programmer it even uses the same wiring and base plate and I used the Horstmann thermostat to replace the current one I had. The thermostat is linked wireless to the Relay, so changes to the stat temperature will call for heat, turn the boiler on or off and in my case the heating pump and motorized valve as needed. The thermostat is also linked to Vera so via scenes you control it to tell it what temperatures to set for the heating and a separate scene controls the hot water by directly turning the hot water relay on or off. If it all goes tit’s up as dominoman said, you can press buttons on the relay one for hot water and one for heating, to get it to run, one thing about the relay is, it times out after an hour so it will turn itself off, if it has not had a request from somewhere to keep running. There is a good set of Guides on the following site which explains in detail how to set this relay and thermostat up.


I’m planning to use this same device too. It’s now called Secure two-channel boiler control unit I’m told.

Can the device work with a conventional wired thermostat. From the documentation I can’t see why not.

In my case I have no interest in setting the temperature. Just turning on and off on a schedule, and being able to switch it all off if I am out late.

I am not sure it would. I have it, and there are no wires going from the thermostat to the Horstman. Everything is via zwave. SO I am not sure if you can get your temperature control via a wired thermostat. It could well ignore the wire input on the thermostat side, but I do not know that for sure, but that is something to check maybe with someone who sells it or the manufacturer

I tried it and it all works as per normal. The ancient wired thermostat still does it’s job and turns off the heating when it reaches temperature.

Ok good to know. If my Horstman thermostat ever breaks down I can replace it as the wires are still there

Just to add my findings - I am also using one of these to control my boiler.

I have a Gravity feed system - ie just the boiler relay for hot water, and then enable the pump as well for Central Heating.
The original backplate is in place, so I could just put the old controller back in. The Room stat is in thus in series, so I have just turned that up to 30c to ensure it stays closed.

The boiler stat was just on the boiler itself, I added a 2-way, hard-wired stat onto the cylinder to improve control, and added a bit of PLEG code to turn on the boiler when the pump was on. (Its “easier” if you have a more modern motorised HW/CH 3-port valve, as that will turn on the boiler for you).

I can post my circuit diagram if anyone wants to see how the wiring goes?

Use the same Secure two-channel boiler control unit here it’s set up with a scene to turn hot water on and off at set times in my case twice a day and another scene sets the thermostat to the temperatures I want during the day and night has worked well for six months but… I am now getting the 1 hour time out on the relay that controls the boiler it has built in if it doesn’t hear from the thermostat. Nothing has really changed in my zwave system that would effect it that I am aware off, and the time out occurs at different times of the day. Not sure it’s the best setup anymore to run my system especially now we are getting into winter, nothing worse than getting up in the morning to a Cold house and then be told by the better half I see Vera has gone on strike again ???

Others have use PLEG instead of scenes.
They have then added addition conditions to send the current setpoint temperature at regular intervals, if heat is needed.

A cold house is one thing … a cold wife is a totally different problem :wink: