I am looking for a smart thermostat/programmer.

[ericmark]

I would like a device that realises when it's going to be a nice day, and turns off the boiler, and one which once the boiler has modulated to full extent and has started to cycle, it again turns boiler off until the weather has deteriorated.

At the moment it is manual, as the weather improves I turn it off for summer, and when it deteriorates I switch it on again. And likely that is the best method!

I have looked at the idea of automation, however with clear skies in summer nights are cold and days are hot, and the idea is to keep house as cold as possible so it does not get too hot as the day progresses.

I did consider the idea of two thermostats and a latching relay, so at a temperature the central heating is never programmed to reach say 22°C it will latch off, and when it had dropped to a temperature below what with would normally allow at night say 16°C it would release.

My home does not heat up quick, nor does it cool down quick, so the other idea is if temperature at say 2 pm outside exceeds a set limit switch off for 24 hours.

I looked at IFTTT and actually tried it, however one day internet failed and as a result heating failed, it's OK getting out the phone and seeing the temperature at home and changing it, but relying on weather reports which can fail.

I have a couple of spare PLC's and a HMI so not a problem making the device, however seems I am reinventing the wheel, I am sure some system already exists, so what is on the market?

 

[MeldrewsMate]

I would like a device that realises when it's going to be a nice day, and turns off the boiler, and one which once the boiler has modulated to full extent and has started to cycle, it again turns boiler off until the weather has deteriorated...

...I did consider the idea of two thermostats and a latching relay, so at a temperature the central heating is never programmed to reach say 22°C it will latch off, and when it had dropped to a temperature below what with would normally allow at night say 16°C it would release.

The simple two point temperature switch can be achieved using the Sonoff TH10 and temperature sensor (assumed to be a thermistor).
IFTTT should then be able to be used to determine (with help from those unreliable weather reports) whether to invoke the use of this switch.

Alternatively more sophistication can be achieved with more effort, using a Raspberry Pi, Arduino, or similar to count boiler cycles (perhaps from boiler flow temperature analyses) and determine the need for boiler operation. The effort required is in the programming.
As with most cases, as the NEED for more sophistication arises, so the cost and effort increases.

My suggestion is to start simple, add complication only if it yields a benefit.

 

[ericmark]

Thank you I have looked at IFTTT not tried Raspberry Pi, did look at Arduino but found it hard to program. Tried to look at boiler return temperature it did not seem to work as expected, it is a Bosch Worcester and I expected to see the temperature raise as the TRV's closed, so I expected it low as it first fired up in morning then raise as the day goes on, however found the reverse.

However will be moving house so moving from gas to oil so will be moving the TRV heads to new house, and starting from scratch, seems new house is a triple S-plan two zones and hot water, and with the two zones where one has to leave house and re-enter through another door so I need some way to monitor and control remotely, likely energenie mihome inline relay model MIHO014 as already using mihome TRV heads.

However not sure as yet maybe Nest would be better? As far as I am aware the boiler is modulating but only 18 to 24 kW.