Heatmiser PRT-TS Wi-Fi thermostat review & troubleshooting tips

I recently decided to replace my central heating programmer with a programmable thermostat, and decided to go for the geeky option: a wi-fi connected model! So I ordered a PRT-TS Wi-Fi from Heatmiser, which can be controlled both via a Web browser and an iPhone app.

Overall, I’m happy with the product but I found it a little tricky to set up. The instructions don’t go into a huge amount of detail, a problem which is compounded by the fact that the Heatmiser support site was devoid of any information on this particular model at the time of writing, so I have discussed my difficulties below and explained how I resolved them.


I won’t go into too much detail on the physical installation, but suffice to say, most people should get the unit fitted by a qualified electrician. There’s only a page and a half of the small (A7 size) manual devoted to it, plus three wiring diagrams, and any mistakes could damage the thermostat and/or the boiler. The thermostat is designed to be flush mounted into a standard 35mm deep single back box. It can be surface mounted but it won’t look as good, particular as the thermostat is a few centimetres larger than the back box at each edge. I chose the latter option to save money, but will have it flush mounted at a later date. I will be interested to see what effect flush-mounting has on the Wi-Fi signal strength, if any.

Appearance & usability

The thermostat is essentially a PRT-TS with an added Wi-Fi card, and it looks exactly the same from the outside. It’s reasonably modern-looking (as far as thermostats go!) with a touchscreen illuminated by a blue backlight. It displays the room temperature in the middle of the screen, which can be adjusting using the up/down icons below it. A slight niggle is that it can be difficult to see what you are doing – the backlight doesn’t come on until you touch an icon, by which time it is too late. I would personally prefer the backlight to come on when touching any part of the screen (not just an icon) and the unit to only respond to icon presses when the backlight is on.

A nice feature is the “Screen” icon which locks the screen for 15 seconds, allowing time to clean it without accidentally activating any functions.

You can also view and set heating programmes, set the clock, enable temperature hold and holiday modes from the touch screen. I found setting the time slightly strange, as the down button changes the hour down and the up button changes the minute up – changing the date works in a similar way with the month and day – but this is something that is rarely necessary to change and can be done from the Web interface or iPhone app anyway.

Wi-Fi setup

Setting up the Wi-Fi connectivity nominally requires a Windows PC and the configuration utility supplied on CD. However, when plugged in via USB, the device presents itself as a USB mass storage device (albeit a very small one: 6.5KB) containing a single file – CONFIG.TXT – which contains the network configuration information in plain text, which could easily be edited by hand by users of other platforms such as Mac or Linux. The file is fairly self-explanatory – the only thing worth pointing out is that the KEYMODE parameter (wireless encryption type) must be either WPA, WEP or OPEN.  There’s a slight security issue in that if someone were to steal your thermostat, they’d have access to your wireless key, thermostat password and PIN, but this is a fairly unlikely scenario!

I had trouble getting the unit to connect to my Wi-Fi network until I switched my router (Linksys WRT54GS with Tomato firmware) from WPA only to WPA+WPA2 encryption. I’m not sure whether this means that the PRT-TS needs WPA2 encryption to operate (despite the configuration utility only showing WPA), or whether there is an issue with my particular router, but if you’re having trouble, it’s worth enabling WPA2 on your router. Before I managed to get WPA+WPA2 working, I tried using WEP encryption as a test but the configuration utility wouldn’t let me save the changes. I didn’t play with the OPEN option, so I’m not sure whether this refers to unencrypted Wi-Fi (and therefore will ignore any username/password) or WEP Open System encryption.

The device requires a static IP address, and port 8068 must be forwarded via the router if remote connection via the iPhone app is required.

It’s worth noting that the front part of the thermostat detaches from the rear, so it can easily be removed once installed, and the front part will power up when attached via USB which means you can set up and test the Wi-Fi connectivity before installing the unit on the wall. This isn’t mentioned in the manual, and neither is the fact that a Wi-Fi icon (similar to the one used on the iPhone) appears on the display when connected successfully.

Browser interface

The browser interface is full-featured if a little basic-looking – it’s reminiscent of a router interface from ten years ago. The so-called “Live View”  panel on the right shows the actual temperature (to one decimal place), set temperature and heat status, and a refresh button as it doesn’t seem to auto-refresh. The main interface allows you to view and adjust heating programmes, temporarily override the temperature, lock the keypad remotely, set the clock and change network settings. There doesn’t seem to be a way to change the port on which the Web interface is accessible, which would be a nice feature to have.

It doesn’t contain any form of logging functionality, so it’s not possible to view temperature changes over time. This would be nice to see in a future firmware update, but I’n not holding my breath.

iPhone app

The iPhone app, a free download from the App Store, is similarly utilitarian. It allows you to see the current temperature (rounded to the nearest degree, unlike the browser interface), set temperature (which can be adjusted) and heat status. You can also view and adjust heating programmes via the app.

One quirk of the app is that you have to select whether you want to connect locally (i.e. when you are on your home Wi-Fi network)  or remotely (via the Internet). It would be nice if the app could determine whether you are home or away and select the corresponding connection method dynamically.

The interface is fairly bland but it does the job. It’s a shame that the graphics aren’t retina ready, so they look jaggy on the iPhone 4 (which has been out for more than a year, so you would have expected Heatmiser to have updated their app!). It would also be nice if a future version of the app came with iPad support – the current version works fine on the iPad but doesn’t take advantage of the bigger screen.

I was left scratching my head for a while, as I was originally able to connect via my Web browser but not via the iPhone app. This resolved itself once I moved my router closer to the thermostat, so it seems that the protocol used by the iPhone app is less forgiving of low signal strength (and potential packet loss) than standard HTTP over TCP/IP. Again this is something that should perhaps be mentioned in the manual.


It’s a version 1 product, so is sometimes a little rough around the edges, but the hardware is solid and the product could easily be improved with updates to the Web interface and iPhone app. The manual is fairly basic, which I can understand is necessary to minimise the size and weight of the box, but why not include a more detailed version on the included CD and/or on the Web?

One final point is that I was slightly perturbed to find that the thermostat, which I paid £150 plus delivery for via Heatmiser’s own shop, is available for as little as £126 delivered from some resellers, so it pays to shop around!


Heatmiser tweeted me and pointed me towards their document download area which contains some useful information. They also say they’re working on a new version of the iPhone app, iPad and Android support, multi-zone and logging functionality, and suggest that users email support@heatmiser.co.uk with any further suggestions.

Also, the £126.20 price I found is actually ex-VAT (thanks Luke!) so it is actually best to buy from Heatmiser directly.

Why I don’t recommend the Belkin OmniView E-Series 4-port KVM


I have acquired a new machine which I’m currently using for Linux (Ubuntu) experimentation, bringing my total up to three, so I decided to replace my old 2-port KVM (a cheap one from Ebuyer) with a 4-port Belkin model from Aria.

It came to just over £33 for the Belkin OmniView E-Series KVM (Belkin part number F1DB104P) and four sets of 1.8m cables (part number F3X1105B) – not exactly expensive, but nevertheless I expected it to work properly, especially with the Belkin name.

I connected up my primary system and immediately noticed visible ghosting/shadowing, similar to what I would expect from using unshielded cables. I was surprised as the cables seemed fairly thick and weighed a lot more than the cables which were bundled with my old 2-port. I’m using a Samsung SyncMaster 173s (17″ TFT) running at 1280×1024 pixels with 32-bit colour and a 60Hz refresh rate, driven by a GeForce 5200 card. Interestingly, the ghosting was less noticeable when using a VGA adaptor on the DVI port instead of the VGA port directly, but it was still there.

Belkin have cunningly used a non-standard cable design – whereas all KVMs I have seen use male PS/2 and VGA connectors on both ends, Belkin KVMs require male PS/2s on either end, a male VGA on one end and a female on the other. This makes it difficult to use non-Belkin cables as neither standard male-male KVM cables (as supplied with my previous KVM) nor male-female KVM extension cables can be substituted.

Out of curiosity, I took the KVM out of the equation and used one of the cables as a monitor extension, plugging the male end into my graphics card and the female end into my monitor’s VGA plug. The ghosting still happens, and reading around suggests that the cables aren’t suitable for resolutions above 1024×768 – indeed, lowering my resolution causes the ghosting to disappear, but this is hardly an acceptable solution.

I have considered returning the KVM and cables to Aria, but their online system refuses to issue an RMA for the KVM until I call their 60p/minute technical support line first, and insists that I must contact Belkin in order to return the cables. On top of that, there is a £2.99 testing fee and £6.95 return postage payable per item should they fail to identify a fault, plus the cost of me sending the item to Aria. So it’s not really worth returning the item for the sake of £33, but I’ll certainly learn from this experience and use an alternative supplier in future.

I have ordered both a VGA gender changer (so I can use my old KVM cables) and an SVGA extension cable (instead of the Belkin male-female cable) to see what works best and whether I’m able to solve the problem myself. The two came to just under £7 from Redfish Computing, a company I found through eBay. I won’t recommend them or otherwise until I’ve received the goods (or otherwise!)

Even if I’m able to solve the ghosting, there are still a couple of annoyances with the unit itself. The beep it makes when switching displays as horrible – much louder than my old KVM – and, more seriously, the mouse goes mad when switching from my Windows machine to my Ubuntu box. I haven’t tested my old KVM on this particular Linux machine, so can’t say if it’s only the Belkin’s fault, but I will experiment later. A couple of things you can try is editing /etc/modules (sudo vi /etc/modules) and changing the psmouse line to:




I haven’t been able to get this working 100% yet – sometimes the mouse still loses control when switching, but I am able to use the keyboard to switch to and log in to a text-only session (Ctrl+Alt+F1) then type the following:

sudo modprobe -r psmouse
sudo modprobe -a psmouse

I can then switch back to the graphical X session (Ctrl+Alt+F7) and the mouse works perfectly, until next time I switch.

I’ll keep experimenting and update this post with my findings, but for now I commend you to think very carefully before purchasing from Aria or Belkin.

Update: I haven’t tried this yet, but according to the fantastic SayNoTo0870 website, it may be possible to reach the Aria technical support team via an 0870 or non-geographical landline number as an alternative to the extortionate 0906 number listed on the website.

Update 2: To make it slightly quicker to fix the mouse in Ubuntu, I’ve created a shell script which runs modprobe whenever I type fixmouse. To make your own, type sudo vi /usr/bin/fixmouse and enter the following lines (press ‘i’ first to enter insert mode):

sudo modprobe -r psmouse
sudo modprobe -a psmouse

Then hit Esc, then ‘w’, then ‘q’ to save your changes and quit the editor. Unfortunately you’ll still have to enter your password unless you have sudo’ed recently or are running in an interactive sudo session.

Update 3: I received my VGA extension and gender changer from Redfish promptly, however the new cable exhibited the same ghosting, as did my old KVM cables and a good-quality shielded VGA cable, although in the latter case it could have been the gender changer that was introducing problems. I’ll try another graphics card in my main PC and see if that solves the problem – I suspect it will, as other computers I’ve tried seem not to exhibit the ghosting issue.

I also noticed that the cables Aria recommended were not the same as Belkin recommend on the box, but that’s probably by the by.

In hindsight, although I’d still hesitate to recommend the Belkin, it’s not a bad unit for the price I paid. However, it is still unlikely that I will be purchasing with Aria again, because their premium-rate support line and over-complicated RMA policy is unacceptable in my eyes.

Update 4: I replaced the FX 5200 card with an ATI Radeon 9250, and the ghosting problem has disappeared. Unfortunately, I’m still getting some noticeable artifacts when I’m using my main machine and one of my other machines (with a Radeon 7500 card) is powered on, but at least it’s more acceptable than constant ghosting.