Underfloor Heating Thermostat to Control an Oil Radiator (BYC07.H3)

NOTE: This isn’t as much of a guide as it is an accumulation of information relating to how to install and setup a BYC07-H3 Underfloor Heating Controller to operate a Oil Filled Radiator.

BYC07 H3 Underfloor Heating Thermostat
BYC07 H3 Underfloor Heating Thermostat from eBay

This is a . I came across this little guy on eBay while looking for something quite accurate and precise to control the climate in my workshop. I had looked at all the usual Central Heating style thermostat products but quickly dismissed most, if not all of them for one reason or another (too expensive, not enough features, not high enough current rating, not sensitive or accurate enough etc).

These inexpensive little LCD Underfloor Controllers fit the bill in every respect.

  • Can handle up to 3kW (my oil radiator is 1.5kW)
  • Easy to read and use LCD Display, timers and menus
  • Two temperature probes (one local and one remote – 3m long) and the option to use one or the other or both probes to take an average reading from the two sensors
  • Super fine temperature sensitivity
  • Easy to install (kind of – the installation instructions that come with it aren’t too great but enough to work from)
  • They are cheap! All those features for the grand total of £14.49
BYC07 3m Long Remote Temp Probe
The BYC07 3m Long Remote Temp Probe



Installing the BYC07 LCD Thermostat didn’t take long. The wiring is very straight forward. A mains feed goes to the terminals shown in the instructions and the radiator or heater simply goes on the output of the thermostat.

I did mine slightly differently in that my output goes to a fused spur and my is hard wired into that. I simply removed the plug from the heater and wired the radiator directly to the fused spur. So in my heating circuit I have a mains feed which goes to the mains input of the thermostat and the output from the thermostat goes to a fused spur and then to my oil radiator.

I did this so I could leave everything installed permanently all year round but during the warmer months of the year I can simply switch off or isolate the heater at the fused spur and roll the radiator off under a bench while leaving the controller to act as a pretty looking temperature gauge.

BYC07 Underfloor Heating Back Plate
BYC07 Underfloor Heating Thermostat Back Plate & Wiring Connections


One thing I should mention is that prior to buying and installing anything, is it’s a good idea to plan out your heating system in advance. My heating system was designed to keep the environment in my shed workshop warm and dry so that all my computers, machines and electronics stay happy all year round.

I took a great deal of time researching and planning down to the smallest detail when building my workshop and insulating it and deciding how I would heat it and combat moisture. Every person’s requirements will be different so it’s worth spending as long as is needed in the planning stages before rushing out an buying anything.

It took me around 6 months to finally decide how I would line and insulate my workshop and how I would heat it and combat the cold, the heat and the humidity. I read everything I could find on the subject of heating and insulating sheds, workshops and other outdoor buildings. I visited the websites of insulation manufacturers and studied their recommendations, I ran though lots of scenarios in my mind (what if this, what if that) etc before I even picked up so much as a hammer.

With this being a subject in its own right, I won’t be going in to detail about insulating etc but just note that plenty of planning now saves plenty of trouble later.

eBay Charles Bentley Portable 1.5kW Oil Radiator
eBay Charles Bentley Portable 1.5kW Oil Radiator


Once I had all of the wiring and connections done (including double checking prior to powering up) I powered up and started to set the Thermostat up to run how I wanted it.

The first thing I had to do was to set up the oil radiator. Now you could (if you know what you’re doing) bypass the Oil Rad’s on board thermostat but I decided against that. I like the added safety feature knowing it will still cut out at the heater directly if anything were to go wrong with the BYC07. So instead of bypassing the Oil Rad’s on board thermostat, I turned it all the way up then backed it off by just over 3/4 of a turn.

This sets the radiators thermostat higher than the range I want the underfloor heating controller to control but still low enough to cut out the heater if anything were to go wrong with the LCD Underfloor heating thermostat. My Oil Radiator also comes with a selector for the heating settings.

I have three positions. Off, Low and High. I tried my radiator on Low for a start but it was just too weak to keep the environment right so I have ended up keeping my heat setting on High.

Once the radiator was set up, I then moved on to setting up the Underfloor Heating Controller.

Programming the underfloor heating controller can be a little tricky to understand at first. My controller didn’t have any instructions with it and at the time, I didn’t even know the actual model number or anything. I simply knew it as an Underfloor Heating Controller.

Before finding a BYC07 Heating Controller Manual I just went by intuition and blind luck – which helped to some extent – but I couldn’t understand why the remote temperature probe wasn’t having any effect when I held it in my hand. After much button pushing I admitted defeat and went about finding out the make and model so I could get hold of the manual.

Once I had found the instructions all became clear. There is a system menu you have to go into to set certain options up and enable certain things. The manual isn’t too bad to follow and I soon worked out how to enable both probes. I can’t remember the procedure off the top of my head but it isn’t hard with the help of the manual.

Once I had configured the Underfloor Heating Controller with the right settings it worked just as I had planned / hoped. I have the heater stood at the gable end of my workshop and on the same wall, about 3ft up and 3ft to the left I have mounted the controller. I then ran the 3m remote probe up the wall and across the ceiling to the center of the roof so it takes a temperature mid way up and then at ceiling height.

I have to say it’s pretty darn accurate too. I have a temp and humidity meter near the end wall opposite my heater and there’s about a 1.5 to 2.0 degree difference between it and the Underfloor Heating Controller temp readings.

I have not had need to play around with the weekly programming schedules so I can’t offer any advice regarding that I’m afraid. I’ve set my Underfloor Heating Controller to come on when the temp drops to X degrees. By default the heater shuts off when the temperature reaches about 1.5 degrees above the minimum value set. But I think you can change this in the system settings menu. 1.5 degrees seems to work okay for me so far so I’ve not had to change it.

Also with my heater being an oil radiator, it continues to raise the temperature beyond the 1.5 degree cut off. So if I tell the controller to switch the heater on when the temp falls to 15 degrees and then it switches the heater off when it reaches 16.5 degrees, the room temp will continue to climb to about 19 degrees and then cool as the radiator looses heat.

So all in all it does it’s job and it does it at least as good as I’d hoped if not better.

Safety First
Safety First



I am VERY paranoid about electrics, fire and safety etc. So much so that for the first week or two after building and testing my heating system I wouldn’t leave it on over night on it’s own. I was just the same after the electrics were first installed in my workshop. I would switch everything off at the consumer unit until I was sure everything was working correct and I could trust the installation.

As I began moving into my workshop and making more and more use of it I began leaving a few things powered up overnight. Mostly the consumer unit and the heating circuit while shutting all other circuits off at night.

I like to gradually break installations in over time until I build up confidence in them and I’m as satisfied as I can be that they aren’t unsafe or pose any kind of danger or risk. I think it was about 2 weeks after installing my heating that I finally had the confidence to leave it on over night by itself.

And this brings me on the the last points I’d like to make before finishing this write up. Much of this relates to workshops but can apply to the domestic environment as well. It’s just common sense and sensible risk assessment mostly.

  • MOST IMPORTANTLY – Please DO NOT attempt any mains wiring / installation if you DO NOT have the required skills / experience – instead seek the help of a qualified electrician.


  • When working with mains ALWAYS double check your connections before powering up. It’s easy to lose focus and get distracted or to let the mind wander too far ahead of the task in hand and end up putting a LIVE wire in a NEUTRAL terminal for example!


  • NEVER completely trust any mains appliance or installation – especially for the first few weeks after installation. Test, test and test some more and even then treat them with respect.


  • ALWAYS observe how much power you are consuming on an HVAC mains electrical circuit or at least how much you are likely to consume. Drawing more Amps than you mains circuits can provide (overloading) will not end well. This is especially important for owners of remote workshops (sheds / outbuildings) where they have fed power to them from the main consumer unit. See Next Item.


  • If you run (or plan to run) power to your out buildings from your household mains consumer unit, it is important to get the ratings of the MCB and the cable you use between the out building and the household consumer unit correct. Anyone performing such a task would be expected to be skilled enough to know this anyway but it’s worth pointing out anyway.Ideally when running mains power to remote buildings, armored cable of the correct rating should be used and all regulations observed when routing the cable and making connections etc.A simple way to work out what rating cable and MCB you need is to add up the total Amps of all the things you’re likely to be running in your outbuilding on that cable and MCB circuit and then add 10 – 15% on to that. From that value you can find the correct rated cable to feed the out building from the consumer unit and also the value of the MCB needed for the consumer unit.You should aim to get an MCB with the closest rating to the value of your total Amperage consumption. E.g. If my Total Amps for my workshop was say 30A IF everything was running at once and then I add 15% to get 34.5A total Current Consumption.The closest I can get to that would be a 40A MCB. Always get an MCB that’s higher than your total consumption but not one that is hugely overrated. I.e. if you consumption is 34.5A don’t go and install a 45A MCB (UNLESS of course you’re planning to increase consumption in the not too distant future).


  • IDEALLY you should install a second consumer unit in the outbuilding that is being powered from the consumer unit in the house. The type of consumer unit and the number of MCB circuits are down to personal preference but at the very minimum I would suggest a which has a total Amperage / Current rating that is near to or exceeds the total expected current consumption we worked out earlier and has at least an MCB for lighting and an MCB for mains power (above but close to the consumption we worked out earlier) to our power sockets.I have linked to the that I use as an example. I do not draw anywhere near 16A on my power sockets at the moment so it’s ideal for me but you should pick one with the ratings and number of MCBs that suit your personal needs. I am planning to upgrade my workshop consumer unit but this was enough to get me powered up and running.


  • Going back to the safety aspects, the main reason I started talking about Consumer Units was to give some lead up to my next point. ALWAYS SHUT OFF WHAT IS NOT IN USE!At the moment I only have one MCB rated at 16A for mains sockets (and of course my 6A lighting MCB). My workshop has been divided into two halves. One half is climate controlled and insulated and is set up as an office so I can keep all my sensitive equipment warm and dry. The other half is just a bog standard “shed” with no heating, no insulation etc and currently has no power sockets. It’s ideal for keeping stuff in that doesn’t need to be kept warm and dry.I did this mainly because it’s cheaper to heat a small space than an entire building.At the moment, I’ve just got the office hooked up to the 16A MCB to one side of my Ring Main making it one big spur (until I run a length of cable from the very last socket in the office back to the workshop consumer unit).But because I want to be able to isolate the mains in the office from the mains in the shed side, I’m going to upgrade my workshop consumer unit so I can have the office ring on one MCB, the shed on another MCB and the same with the lighting. Each side will have it’s own MCB so I can shut down the shed side of the workshop at night.

    I want to be able to isolate and shut off as much as possible at the Consumer Unit as I can while leaving on only the essential stuff (heating, extraction fan) that needs to be running.Prior to locking up the workshop at the end of the day I always go around checking every plug socket to make sure that things don’t get left on over night such as Soldering Irons, Computers, Printers etc. Only the bare minimum remains powered up at night. It only takes one time to slip up and that’s the time all the hard work goes up in smoke!!!!!


  • Speaking of smoke – INSTALL A SMOKE ALARM. They are so cheap to buy these days that I think anyone that doesn’t have one is a fool asking for trouble. Yes they can be annoying and seem to have a hatred towards anyone making toast but they save lives and property and every home AND workshop should have at least one.My workshop is alarmed at all times when not in use and it’s possible these days to get inexpensive smoke detectors that communicate with the alarm panels. When the goes off, it triggers the alarm to go off too. So if you’re workshop is remote from the house you might not hear it bleeping away but if it’s connected to the workshop alarm EVERYONE will hear it. It might make the difference between not hearing it and finding a pile of ashes in the morning or hearing it and getting to it before too much damage is done.


  • GET A FIRE EXTINGUISHER – These are so cheap these days that no home or workshop should be without at least one Fire Extinguisher and one Fire Blanket. I picked up a on eBay for around £22 – £25. I have one installed in my Kitchen and one installed in my Workshop Office. I also have a Fire Blanket in my Kitchen but not in my Workshop – yet.If you’re a maker / tinkerer or whatever and you have yourself a bit of a man lab you’re bound to get into trouble at some point when making the smoke come out of things. Best to be prepared 😉

And I’ll think I’ll wrap up this entry at that. There’s plenty to consider and take on board. Hopefully it’s been helpful to someone – even if it’s a little long winded. Staying safe is just a case of thinking ahead and using common sense.

Once you get into a mindset and routine of looking for potential danger and risks and in the habit of turning stuff off when not in use etc it becomes second nature. I know it all sounds a bit “Health and Safety” and I know how mad some of those “Elf n Safety” folks can be but there’s no need to take it to the extreme. Just a bit of common sense and you’ll be good.

And remember, if in doubt, get a professional out!

Stay safe 🙂

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