Heatmiser networked stat support (UK & EU)

I have a John Guest networked heating system, which has thermostats in each room, networked to a central control box, and controlled via the web or via a touch screen panel. It’s a branded version of the Heatmiser system (http://www.heatmisershop.co.uk).

I wanted to integrate it with my MiCasaVerde, so I wrote a device controller to read and write from the NETMON networked controller. I have attached the files here in case anyone else has the same system and wants to make use of it. If you do, let me know how it goes.

See the readme in the attached zip file for instructions.



Those systems become increasingly popular int the EU… :slight_smile:

Hi Martin

I’m looking to get a new room Thermostat, can you explain/point to the place where this NETMON controller is? The link points to thermostats, unless you mean the Central Control Unit they have lited there?

Interesting thread. I’ve also written a Heatmiser plugin - it was done early this year, but since I had other jobs to do, it wasn’t fully tested. This is now proceding and I’ve integrated the PRTHW and am about to integrate another controller (this weekend) for the new underfloor heating in the extension.

I assume that the NETMON device is the Heatmiser network interface? This is quite expensive and I used a similar device off eBay which cost around £30 from memory. It seems to work pretty well… (it from a company called Hexin).

It is probably worth us working toward a common Heatmiser plugin. The Heatmiser networked units are reasonably nice, and when integrated with other sensors (eg One-Wire or Z-Wave) through Vera, it makes for a very good little system…


I have a Heatmiser wi-fi thermostat and I currently get the temperature and set-point into Vera using the thermostat’s web interface and a Raspberry Pi. I’ve just finished developing a plug-in for my security system and the Heatmiser was next on the list. The only problem I can see is that the wi-fi version requires a CRC at the end of every message; I need to find out how to generate this CRC in Lua…

I think the WiFi version is very similar to the network version, and I’ve already coded the CRC routines (it took a while, but it works fine…). I think the code you need is this -:

-- Heatmiser CRC functions
local CRC16_LookupHigh = {0,16,32,48,64,80,96,112,129,145,161,177,193,209,225,241}
local CRC16_LookupLow  = {0,33,66,99,132,165,198,231,8,41,74,107,140,173,206,239}
local CRC16_High
local CRC16_Low

function CRC16(buf, len)
  CRC16_High = 255
  CRC16_Low  = 255

  for cnt = 1, len, 2 do
    val = tonumber(string.sub(buf, cnt, cnt+1),16)

  return CRC16_Low, CRC16_High

function CRC16_Update4Bits(val)
  local  t

  t = bit.band(bit.rshift(CRC16_High, 4), 15)
  t = bit.band(bit.bxor(t, val), 15) + 1
  CRC16_High = bit.band(bit.bor(bit.lshift(CRC16_High, 4), bit.rshift(CRC16_Low, 4)), 255)
  CRC16_Low  = bit.band(bit.lshift(CRC16_Low, 4),255)
  CRC16_High = bit.band(bit.bxor(CRC16_High, CRC16_LookupHigh[t]), 255)
  CRC16_Low  = bit.band(bit.bxor(CRC16_Low, CRC16_LookupLow[t]), 255)

function CRC16_Update(val)
  CRC16_Update4Bits(bit.rshift(val, 4))
  CRC16_Update4Bits(bit.band(val, 15))

In your init code, you then need to add the line “bit = require(“bit”)”.

I think that should do it, but it’s possible I’ve missed some bits as I wrote all this at the beginning of this year and am only just getting around to installing the heating in the extension now!

My current plugin just does the basics - sets/reads the setpoint and other config data, reads the temperatures, on/off state etc, and allows setting of holiday mode. It also syncs the time on all the thermostats on the system. For the hot water thermostats (PRT-HW) it provides two separate thermostats in Vera - one for the water, and one for the heating… I haven’t (yet anyway) added anything to manipulate the heating schedules as my main driver is to be able to read the temperatures and override the setpoints…

If there’s interest I can look at releasing an “alpha” version… I hope to have a second thermostat installed tomorrow for the underfloor heating and may need to change a few things to support the different thermostat model, but then the basic functionality should be reasonably complete…


Thanks Chris. I didn’t realise that the network version requires a CRC too.

I’d be very interested to see your alpha code. Perhaps I could add the wi-fi functionality to make it a universal plug-in?


My original intention was to support the WiFi as well, but there’s the model is slightly different. For the network version, all comms has to go through a parent device that can look after the RS422 bus traffic and handle the IP connection. However, for the WiFi version, each thermostat device can communicate separately with the thermostat. I had a few ideas of how to make it universal, but never got around to implementing anything…

In some ways, I like having the parent device - while not quite implemented yet (since I only have 1 thermostat in my network right now - although that will change in about an hour!) I plan to use the parent to provide overall system control. ie when you go on holiday, you just set holiday mode on the parent, and it sorts out setting all the thermostats in the system…

Given the similarity between the two systems, it makes a lot of sense to keep a common codebase so if you can look at the WiFi side, that would be good. I’ll take a look at apps later and see if it supports multiple users editing an app (but I suspect not) and we can work out how to manage this… Anyway, I’d better do some DIY for a while or the other half won’t be happy… :wink:


Sorry for the slow response… My company sent me abroad at short notice for the week, so I’m just catching up with things…

The HeatMiser plugin has been working well for the past week - I’m not using HeatMiser to control the heating yet, but I’ve had 2 thermostats running and talking to Vera all week. Unfortunately I’ve had to send one back to HeatMiser as it wouldn’t let me select the external sensor which is burried in the floor (they say it might be programmed with the wrong software!!). I’ve had it logging temps to dataMine all week and it’s worked fine…

I’ve attached the plugin here if anyone wants to play with it. I’ll also release it through the app store for the simple install option ;).

Once the plugin is installed, you need to set up the IP address for the network interface. I used a Hexin interface off eBay - it cost something like £35 rather than the £100+ that HeatMiser charge for theirs. Interestingly, the Hexin device looks “rather similar” to the HeatMiser one. If people are interested in this option, I can post information on wiring it up (it’s just two wires and power).

You then need to add thermostats. In the device properties there’s a box to add the thermostat model, and the network address (models can either be PRT, or PRT/HW at the moment). With the HW, two Vera devices are installed - one for heating, and one for the HW system… The rest is reasonably self explanatory (I think), but feel free to ask questions or make suggestions…

Any comments/improvements welcome…


Hi folks. Sorry, I wasn’t getting any notifications from the forums about your questions.

Yes, you need a NETMON box for the wired system to be controlled over TCP/IP. It is the thing that a) sends commands to the thermostats, and b) polls the thermostats for an update. They aren’t £100, they are more like £400;


As I recally, the protocol for talking to the thermostats is unoficially documented somewhere, so I have no doubt that someone could produce a MUCH cheaper version of it. But if you want the officially supported one, that’s what you need to get. On top of a complete individual room wired wired heating system, it’s a small extra cost. But if you just have one thermostat, it’s a massive cost.

I don’t have any wifi thermostats - I decided to go wired because wifi isn’t brilliant in my house. The walls are too thick. But disapointingly the wired connections aren’t 100% reliable either. That’s why the plugin auto-retries until it successfully sets the data.


I used a box of eBay which cost £35 - works a charm :slight_smile:

Yes - that’s exactly what I used in the HeatMiser plugin - the £35 interface, and some code to implement the interface. :wink: I’ve currently only implemented time synchronisation, readback of the configuration and ability to set the major variables. I think there’s a few issues that need to be sorted out, but it’s working ok for me.

I’ve found the wired system to be pretty reliable so far - I’ve only got 2 thermostats wired to it, but it seems quite reliable using the Cat-5FTP that Heatmiser recommend.



I’m quite new to Z-Wave and Vera, but am keen to learn…

I have just had an underfloor heating system installed and the Heatmiser Thermostats are about to be ordered. I want to be able to adjust the temperature using scenes on my Vera and would like some advice on which wireless thermostatas will be the easiest for me to integrate and and details on the cheaper alternative to the Heatmiser Netmonitor (if that is what I need).

Many thanks in advance for any help/advise you can offer.


Hi Martin,
I just thought I’d post a couple of things here following our discussions in case it was of interest to others… I had a look at the UH1-W, and it doesn’t include any network connections. The UH-1 for the network thermostats does very little for the network - it has no intelligence, it just connects the network link through to the CAT-5 connectors, and the thermostats do all the smart stuff.


So, I think if you want to be able to control the Heatmiser thermostats remotely (be it from Vera, or anything else), then I think you need to use either the WiFi versions, or the network versions - I think both need wiring though as the WiFi ones require power.


Hi, I just wanted to re-ignite this thread as I’m at the point where i need to replace my existing thermostat and I’m tempted by the Heatmiser (maybe the PTS-Wifi), although I’m open to suggestions.

I’ve got the Horstmann HR4-ZW in use but I’d like to have something fixed (a single device connected to the existing 230v feed in the hallway where the current Honeywell Dial one is located) rather than another 2 part wireless unit.

How are those of you with the Heatmiser getting on?
How reliable is the wifi version, compared to the wired?

I’m a big fan of the Heatmiser thermostats. The PRT-TS Wifi’s I have (x2) have been ultra reliable, and the integration with Vera is nice, although I’ve not automated anything yet with them, so can not comment on that yet.

Same experience as quinten. I have a WiFi Heatmiser and it just works. :slight_smile:

Has anyone got Chris’s plugin working with a proper Heatmiser Netmonitor interface?

I can control the thermostats through the netmonitor web interface, but I cannot get the plugin to control the thermostats or even just get the temperature back from them.

I’ve tried various port numbers that people reference across the web 80, 8086 and 8078.

Any ideas anyone?

Hi all.

I have a Heatmiser PRT/HW-WTS, (CH, HW, wireless control and WiFi access) which I’d like to try to integrate into my Vera Plus. I’d be most grateful for any advice, and access to any suitable plug in.

Thanks in advance

Have a look here: Support for Heatmiser WiFi Thermostats

Thanks for the pointer. I’m now in poessesson of the appropriate plug-ins, thanks to racarter. I’ve already installed them and things should hopefully headed in the correct direction for a fully functional smart heating system.

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