"This thermostat is the best I've found. It doesn't show off with a big screen and LED lights, it just does it's job excellently. In my house it routinely controls to exactly the set temperature. If set to 20.0, it controls to 20.0. Not 19.9 or 20.1.
Some reviews have complained about "excessive" switching, but this is exactly how it achieves such precise control. It switches on and off again once every 15 minutes (on for a variable amount of time each time, depending how far from the desired temperature you are). This control method is called PID (google it) and is used universally used in industry for all kinds of control applications. There is nothing better.
One review mentions that the temperature reads wrongly in his house. I haven't had this problem, but the manual will tell you how to apply a temperature offset if this problem affects you.
The min max set points can be limited (great to avoid kids / non-gas-bill payers ramping up the gas bill), and if necessary the whole control can be locked to avoid any tampering at all."
"I bought this as an add on for my central heating and fitted it within minutes, two wire operation from boiler to the unit so bear in mind it's not wireless, however I was only going through the wall to living room, very easy to fit and does not look out of place next to light switch. You won't go wrong for price and it will save money on your heating, so it will pay for itself in 12 months."
"A better designed product than the former unit although not quite a straight swop, the terminal connections are different. The unit controls more accurately being able to control to 0.5 degree C rather than a full degree C."
"I bought this programable digital thermostat to replace an old mechanical room thermostat. Easy to install and set up straight form the box. The ability to programme the thermostat to meet my family's needs on a daily basis has made a real difference to how we now heat our house. Excellent product."
"I just wanted support the previous reviewer. This thing does cause the boiler to switch on and off several times before reaching the set temp. Maybe it's just being frugal with my gas - I don't know. It takes a long time to heat up the last degree.
I've only had mine 18 months, so no dead battery experience yet.
Apart from the design feature mentioned above, this is a pretty good bit of equipment. programming is very flexible and will do everything you want and more. There are lots of options. Instructions are perhaps not well written."
"Bought & fitted one yesterday. Does what it says on the box. I had a Digistat 2 that packed up and Drayton Technical Support recommended this as a replacement as I wanted more functions. They were very, very helpful, explaining how to transfer the wiring from one model to the other. I wonder if some of the other comments here refer to the wireless model that has a 'learning' mode, which this one has not. Only niggle I've found so far is that it seems to under-read the temperature slightly, for instance displaying 20 when 2 other digital thermometres say 21, so I've set the required temperatures one degree lower and all seems well."
"Bought to replace an electronic thermostat, this provides far better and more flexible temperature control. Like the holiday function, that allows you to set back the temperature while the house is empty but turns the heating back on for your return. Only gripe is that there is no facility for remote control, by text for example. Easy to instal and program."
"The digistat relay took a bit of "nud ging" before it finally began to switch the heating on and, compared with my previous 10 year old digistat, there seems to be quite a delay before it registers a change in room temperature."
"This was fitted by plumber along with a new boiler. Like many electronic products the instructions and design are overly complicated . However my main problem is that the programme 'froze' on occasions meaning that the boiler stayed on and the temperature kept going up. We only spotted this when we woke in the middle of the night. None of the buttons would work, the display was frozen and the only thing to do was to remove the batteries. As soon as I put the same batteries back it worked normally. This happened on a couple of occasions. I contacted Drayton who said that it seemed that there was a problem with the chip and sent me a replacement. It is now doing this again so I will replace it with a non-Drayton thermostat. An earlier reviewer (SBEDIYer) seems to have had the same problem but interpreted it as failing batteries. I suspect he had the same problem as me. The impression I got from Drayton Customer Service (who were very helpful) is that this is a common problem."
"Have had one of these for 3 1/2 years. It switches the boiler on and off 6-7 times, for betwen 10-15 mins each burn, before the house reaches the set temmperature. This can't be doing the boiler any good. Now after 3 years I am expecting the thermostat low battery warning icon to appear. Nothing. Then mid day the house goes cold. Thermostat showing heat demand, boiler not doing anything. The thermostat battery has gone low volts and is not picking up the thermostat output relay. Low battery warning icon not appearing. Thermostat batteries renewed, all now working again. I would not recommend."
"I had the original Digistat 3 and it was brill. When it failed after many years I purchased one of these. It has been connected 2 days and I am having problems maintaining an even temperature. Having had the old one which was great I decided not to give up with this one. So I have contacted support at Drayton (Really Good Support) and I now have an understanding of what the stat is trying to do. You have to put it in set it and leave it for 5 days. It will go over the set temp and it will cut off early. It is learning about the conditions in the house (Heat loss ect). I was told that all stats in the future will be made this way for energy saving. I will let it run and report back in a few weeks
This was sent to me from Drayton Support it might help you.
Digistat+2 and Digistat+3 Control Function Explained • Digistat+2 and +3 uses a Pulse Width Modulated (PWM) system. • A 15 minute cycle time is used. • The output is on for a proportion of the 15minute cycle determined by a function of the difference between the set point and the measured temperature. • While the measured temperature is more than 2 degrees below the set point, then the output is continuously on. • While the measured temperature is more than 2 degrees above the set point, then the output is continuously off. • Between these limits, at the start of the 15 minute cycle, the Digistat makes a calculation of the required on time of the output. • It makes a new calculation at the start of every successive 15 minute cycle. • The calculation aims to reduce the difference between the measured temperature and the set point. • It tries to compensate for the heat loss it expects over the next cycle with the heat input it expects from the on time of the heat source (normally the boiler). • The longer the Digistat is at one set point, the more accurate will be the calculation and the closer will be the control to the set point. So, to answer some comments that have been made: – The boiler is switched too frequently. • No it is not, a 15 minute cycle is compatible with the control accuracy we are trying to achieve. – The displayed temperature is not at the set point. • True, most controls have an similar accuracy, but we display to 1/10th degree resolution so any difference is more noticeable. – The display temperature is above set point, but the boiler is on. • This is not inconsistent with the algorithm. It is trying to predict the losses for the next 15 minutes, and supply sufficient heat to compensate. – The display temperature is below the set point, but the boiler is off. • This is not inconsistent, the control will try to inject sufficient heat to compensate for the losses and lift the controlled temperature to the set point and no more. If it calculates that it requires 2/3rds of the boiler output to achieve that, it will switch the output on for 10 of the 15 minute cycle. The boiler will be off for 5 minutes. Remember the thermostat is about setting a comfort level, not a specific number. Position of the thermostat and system conditions play an important role."
"Like other reviewers I became very frustated when the thermostat decided that it could either wait to heat the house when we were all cold or heat it when the house was too warm. All due to a "clever" algorithm which cannot be overridden. I changed it for a Danfoss TP5000Si which also has an algorithm BUT it does allow you to turn this off and use the old style of control - peace has returned to my house!"
"I purchased this thermostat to replace a manual one. I had nothing but problems as It never reached the temp I programmed. I bought another one thinking the unit was faulty. Same problem. After speaking to tech support at Drayton (Very good) this is a common problem as the unit has to climatise & learn your individual needs (built in to firmware). This cannot be removed. After 8 weeks I still have a hot or cold house & the unit is still trying to climatise. I am looking at alternative digital thermostat."
"I bought the Digistat+3 a year ago and was constantly confused about what it was doing. It seemed to turn off the heating before the target temperature was reached and randomly switched on for a couple of minutes at a time during the night. After belatedly reading the reviews here, I now understand about the crazy algorithm built in to this device which means that it doesn't actually do what it says in the instructions. The whole thing seems pointless to me because I constantly have to adjust the temperature to get the heating to stay on, so I might just have well used a simple switch. It clearly isn't worth the money and there are better devices at just over half the price. The manufacturer suggested that I buy a different unit! I suggest that you do too."
"Have been using this model now for 18 months after deciding that having a temperature profile for week days and weekends would be a good thing (aka saving money). However the unit is rather difficult to program but it has a fundamental flaw. It is battery powered and there is nothing on the display to tell you the battery should be replaced. When it reaches the point where the battery voltage is too low for it to function it stops working in a state where it is telling the boiler that heating is required (the display remains on but the unit doesn't respond to button presses). If you like me use the thermostat to control the heating and the boiler control is effectively on 24/7, then you will find the boiler constantly on heating the house. This has now happened 3 times so I've had to resort to replacing the batteries every 3 months."
"Strongly DO NOT recommend the Digistat. Two wire install is easy, but it's complex to set up and adjust. All importantly though, in operation it's a disaster and I've taken mine out. It switches very frequently(!) and the relay has a very loud click which is intrusive in a living room - everyone looks up every time it switches. Temperature is also unstable. I have gone back to a conventional thermostat, which is much better - and would be cheaper had I not wasted the cost of the Digistat..."
"As other people have said this unit tries to be clever but fails. I have had the unit now for over 6 months and it is still messing around trying to be clever and failing. I would not but anything as "clever" as this - just stick to something simple that turns the heating on when it is too cold and off when it is hot enough. Over complex solution to solve a very simple problem and hence is rubbish."
"I bought this for its wealth of features (holiday setting, intelligent startup, six daily heat periods, easy override) but it's too clever by half. My greatest frustration, like PJGT, is the unit's inability to maintain a steady temperature: the house is either too hot or too cold. This is partly due to the very wide temperature gap between switching off and switching on (hysteresis, I believe it's called) and partly because often you find the controller demanding heat when the temperature would indicate you don't need it (and vice versa). If the latter is down to "learning mode", then all I can say is mine is still learning after a year! Additionally, intelligent startup could save energy but its method of operation is not explained (you select it, close your eyes and assume that the unit is magically saving you heat)."