Choice of thermostat advice please

[diselsamm]

Update2: After a further monitoring, it seems the cycling was actually resolved. The boiler turns on about every 10 minutes, which is as expected. At this point I am not sure anymore whether it is worth it to replace the receiver and thermostat.

 

[John.g]

I cant find any info on that stat as to its hysteresis or if it is a TPI controller, I have a basic digital roomstat set to its minimum differential setting of 0.3C, (it has no TPI) it switches in when the room temp is 0.15C below its SP and switches out at at SP with ~ 0.2C overshoot after room heats up after initial heating say in the morning, its surprising how long it takes to increase the temperature by that 0.35C, over 10 minutes normally with ~ 25 minutes off time (oil fired boiler).

 

[diselsamm]

John, I am not sure whether your screenshot is for your thermostat, but it is exactly the same for mine. 6 cycle ph, 1 minute min ON time.
The way I think about this is that a good thermostat should be able to monitor the outside temp and learn/so anticipate the heat loss of the house and work around it. In the real world I do not know how closely my existing thermostat is able to do this and whether there is a sizable margin for improvement or it is good enough. In the end my boiler is an on/off thing which by default means its control is not precise.

 

[ShaunCorbs]

John, I am not sure whether your screenshot is for your thermostat, but it is exactly the same for mine. 6 cycle ph, 1 minute min ON time.
The way I think about this is that a good thermostat should be able to monitor the outside temp and learn/so anticipate the heat loss of the house and work around it. In the real world I do not know how closely my existing thermostat is able to do this and whether there is a sizable margin for improvement or it is good enough. In the end my boiler is an on/off thing which by default means its control is not precise.

You can get that but you will have to change your boiler as it’s a dumb control wise

 

[John.g]

John, I am not sure whether your screenshot is for your thermostat, but it is exactly the same for mine. 6 cycle ph, 1 minute min ON time.
The way I think about this is that a good thermostat should be able to monitor the outside temp and learn/so anticipate the heat loss of the house and work around it. In the real world I do not know how closely my existing thermostat is able to do this and whether there is a sizable margin for improvement or it is good enough. In the end my boiler is an on/off thing which by default means its control is not precise.

That info is from your stat, cant find any info from Honeywell. All these "clever" control systems like evohome will constantly cycle the boiler on and off even when the heat demand is > than the boilers minimum output to give pinpoint temperature control. Weather Compensation is best utilized IMO by controlling the boiler target temperature but the boiler has to be able to use this.

 

[diselsamm]

To be fair I am not sure what better a boiler is there on the market compared to mine. Mine is a detuned 12 kW greenstar RI. 45dB noise, modulating in the 4-12kW range. Simple and simple to fix. I have a one zone Y system.

 

[John.g]

Your heat demand will rarely be much lower than 4kw but if your existing stat has TPI control then it will cycle it on/off, you should be able to buy a relatively fairly basic digital stat, if you do purchase one ensure that its one with a low differential of 0.2C/0.3C and where the TPI control can be disabled or one without TPI, like mine.

 

[diselsamm]

I am thinking about Honeywell Y87RF2024, which will be a direct replacement for my current setup, keeping the old programmer. Unfortunately I can't find much info on how that thermostat operates. This and I am not sure of the benefits of this replacement thermostat over the analogue one I currently have and which seems to be working fine.

 

[gmartine]

Smarter stat systems uses geolocation to get local temperature if weather comp not used, my very old mother (92) has your boiler (9kw) bolted on to tado in a 3 bed semi. Seems to work ok, target temp is 22.2 deg C.

 

[diselsamm]

I am not sure I am comfortable with my skills to replace my Honeywell controls with Tado. I think I also have to take down the programmer which will cause cosmetic issues (I know!). I am comfortable to replace myself my receiver and thermostat with the Y87RF2024, and keep my programmer, which works fine. The question is, is it worth it?