heatmiser RF switch not enabling boiler

[williamness]

Boiler is a Viessmann 100-w (2021 version)
heatmiser uh8-rf
heatmiser rf switch (intended for boiler enable only)
Heatmiser neoair thermostats

I live so far north that there isn't a Viessmann installer local to me, however after speaking to Viessmann my local heating engineer was placed on a training course with Viessmann to install my boiler. It was installed today but the heatmiser rf switch will not enable the boiler.

the setup is as follows, 8 radiators over 7 zones (living room has 2 rads)
all rads go back to a 7 port manifold.

heatmiser thermo heads on the manifold.

the neoair is paired with the uh8-rf and the uh8-rf is paired with the switch, this is working as when the temp is set on the neoair the flame icon lights up, it triggers the uh8-rf and in turn that lights up the rf switch next to the boiler. but then nothing happens. there are no valves or pumps or anything extra fitted to the system, its just 100-w, the heatmiser electronic stuff and radiators.

Does anyone know why this isnt working.? the rf switch is wired to port 96 (Configurable floating input lH, 230 V) and set in the configuration as no 4 "external demand"

any help would be greatly appreciated.

 

[ShaunCorbs]

Best get him to phone technical

 

[williamness]

Best get him to phone technical

Viessmann or heatmiser?

 

[ShaunCorbs]

Viessmann as it needs setting up in the control panel

 

[williamness]

Viessmann as it needs setting up in the control panis this something thats in an installer only control panel as

firtsly, thank you for replying, is this an installer only control panel? or a setting i could input/change if i knew what menu to go into.

 

[ShaunCorbs]

Installer as if you mess up it could alter something else

 

[williamness]

Installer as if you mess up it could alter something else

can i just confirm you are talking about a different commissioning sequence than "C.14" plug 96 function - which has been set to : 4 - External demand and verified at least twice.

 

[ShaunCorbs]

Yes 96 plug pin label 1

 

[Gerardo]

I am encountering the same problem with a Viessman 111-w (which I believe is the same system as 100-w but with integrated storage tank).
Did you manage to work things out your end? If so would you mind sharing how?

I have two controllers wired to the same terminal (i.e. plug 96). Drayton Wiser to control the radiators zones works without any issues. The RF switch for UFH, boiler light comes on but the boiler does not turn on using the exact same wiring as the Wiser controller.

Any ideas how to get the RF Switch working?

 

[Gerardo]

I finally managed to get the problem resolved. Based on the same principle my Drayton Wiser controller was using I decided to try the same on the RF Switch. Basically the RF Switch manual does not tell you that LS and LR output contacts are voltage free. You need to link L with LS in the RF Switch to get voltage on the contacts (i.e. run an extra small cable from L to LS). Once the Switch receives the boiler-enable signal, the voltage in LS is sent to LR which enables the boiler.

On plug 96 of Viessman you connect L, N and the LR from the Switch.

I hope this helps you!

 

[Timmy D]

I finally managed to get the problem resolved. Based on the same principle my Drayton Wiser controller was using I decided to try the same on the RF Switch. Basically the RF Switch manual does not tell you that LS and LR output contacts are voltage free. You need to link L with LS in the RF Switch to get voltage on the contacts (i.e. run an extra small cable from L to LS). Once the Switch receives the boiler-enable signal, the voltage in LS is sent to LR which enables the boiler.

On plug 96 of Viessman you connect L, N and the LR from the Switch.

I hope this helps you!

I haven’t logged on for a while and just seen your post.

Although you didn’t get the help you required, thank you for the update.

 

[Mattcf]

I finally managed to get the problem resolved. Based on the same principle my Drayton Wiser controller was using I decided to try the same on the RF Switch. Basically the RF Switch manual does not tell you that LS and LR output contacts are voltage free. You need to link L with LS in the RF Switch to get voltage on the contacts (i.e. run an extra small cable from L to LS). Once the Switch receives the boiler-enable signal, the voltage in LS is sent to LR which enables the boiler.

On plug 96 of Viessman you connect L, N and the LR from the Switch.

I hope this helps you!

Hi Gerardo, thanks for your tips - they’ve been very helpful. With your nest set up do you use this to control the hot water or can you still have that switched on all the time on the boiler itself?