Programmable Thermostat

[AndyPRK]

Hi

I need a new thermostat. What a minefield!
Any Help welcome.

I don't need to control it remotly from the house! though if it had that additional feature it would be ok.

Requirements

1) Don't want it battery operated. So I want the sensor and wiring into the wall.
2) ideally square, similar size to a light switch but I know its going to have to be a little bigger.
3) different temperatures at different times of the day. (at least 4 periods)


Thank you

I saw a Timeguard TRTWIFI but I think its battery operated

 

[CBW]

What about a Nest? Technically it’s battery, but rechargeable and fixed to the wall in place of existing thermostat, or powered by usb. I think a lot of prog stats are battery as well as mains, or standalone battery, eg wireless.

 

[ericmark]

Screwfix do a programmable thermostat for around £35 but first you need to decide what type will be best.

A oil boiler only needs switching on/off, but a gas boil often modulates, I.e. it reduces output, that are two main ways to control modulation, one is by temperature of return water, the others is a thermostat which can turn boiler up/down rather than on/off.

The thermostatic radiator valve (TRV) is often the main control, but unless wifi linked it has a problem, in it can't turn the boiler fully off, so needs an on/off thermostat so it totally switches off.

So there is no reason why a programmable TRV and wall thermostat should not be set to complement each other, but also can work the reverse.

So first what boiler do you have, and what style of home, my old open plan worked well with one central wall thermostat, but this house with doors on the rooms is completely diffrent.

I tried to get my mothers house working well, and realised the TRV is king, easy way is an expensive system like Honeywell evohome or Drayton wiser, but you can often do it cheaper.

 

[AndyPRK]

old drafty house.
No boiler modulation.
No TRV's valves (removed many decades ago apparently)

 

[flameport]

Danfoss TP7001M
Mains powered, switching can be any voltage so works with pretty much any heating system.
6 different temperatures per day, 7 different days per week.
Doesn't have wireless, internet connection, batteries, spying eyes, microphones or any other useless nonsense.

https://www.cef.co.uk/catalogue/products/4389028-tp7001m-24-hour-programmable-room-thermostat
Make sure to get the M version, the TP7001 is a battery powered piece.

 

[ericmark]

Last time I used a Flomasta 22199SX which is cheap and did do the job, but found the programming needed the book each time. The old Hortsmann DT2 it replaced was only 4 not 6 programs but far easier to use. With mother I tried a Horstmann HRFS-1 the spec was A1 and wireless, however it kept loosing the RF link and no fail safe, this house used a Nest Gen 3, again faults, in it does not connect with TRV heads, but must admit easy to use, turn outer dial up or down and large display.

So back to basics, the TRV is king with gas modulating boilers, you can get cheap programmable heads, pre brexit the eQ-3 non bluetooth was around £10 and with bluetooth £15, the Terrier i30 was also cheap, since brexit the prices have risen, but the problem with non linked TRV heads is they do not turn the boiler off, so it sits there cycling on/off unless there is a wall thermostat.

So again keeping it basic you want a wall thermostat set so when we have good weather it turns off boiler, so in the hall TRV set to 17°C and wall thermostat set to 19°C and since mounted higher than TRV if weather improves it switches off.

Next stage is programmable TRV and programmable wall thermostat with same schedule so can switch down when not required.

And next stage is linked. Again keeping cost down, only needs one or two TRV's linked to the wall thermostat, likely cheapest option is Hive. Hive has demand for heat system so the TRV can keep boiler running when required.

The Drayton Wiser and Honeywell EvoHome do a fully integrated system including if single channel Opentherm where the thermostat turns boiler up/down rather than on/off. With multi-channel the EPH thermostat can work as master/slave with OpenTherm, but does not connect to TRV heads.

I tried geofencing, and this relies on the TRV as with my TRV head the anti hysteresis software was too good, so took too long to reheat, the Drayton Wiser claims to work out when it needs to close the TRV so is faster at reheating rooms when required.

But this house not heating times, but cooling times which cause the problem, the hall cools too slow, so living room cold before wall thermostat in hall turns boiler back on, unless I wedge open door between living room and hall.

Hind sight, and hind sight is easy, Hive would have been better than Nest Gen 3 which I fitted. But a gnome against the living room door to hold it open works fine.