Replacing a thermostat
Posted: September 10th, 2019, 11:20 am
Wonder if anyone can recommend a way forward.
I have a combi boiler in the loft, vokera 29e, and this has a 24 hour rotary timer on it, (ie, not 7 days, or programmable).
Connected in the living room is a very old style thermostat. It has 4 wires as seen in the following pictures (should be 4 pictures on this link)
https://imgur.com/a/qWky58B
As I can only control the timing from the loft, I want to change the system slightly. Seems like I have 2 broad options.
1) new wizz bang smart system like honeywell evohome - total cost about £600
2) swap out the thermostat with a programmable one, something like honeywell t4h110a1021 - cost about £60
As can be seen, thermostat has 4 cables, earth, break on temp rise, spare terminal, common. I’m a little confused by the blue wire on the spare terminal, as in the loft only 3 wires arrive (on the left hand side of the wiring picture). Is it possible that the thermostat also takes power directly from a separate mains feed, rather than the boiler?
There is 240v between earth & “break on temp rise”.
So, my question is, does it make sense to replace the thermostat with a basic programmable 230v thermostat, and then turn the boiler to “on 24 hours”?
The evohome system seems tempting, but will require me to get a plug socket installed in the loft, not the end of the world I guess. Ultimately I want to be able to set the heating to come on/off at different times depending on the day. Long term it would be be nice to go down the whole evohome setup, where you can control room temp individually with digital trv’s
Appreciate any thoughts, apologies that it’s all a bit rambling.
Paul
I have a combi boiler in the loft, vokera 29e, and this has a 24 hour rotary timer on it, (ie, not 7 days, or programmable).
Connected in the living room is a very old style thermostat. It has 4 wires as seen in the following pictures (should be 4 pictures on this link)
https://imgur.com/a/qWky58B
As I can only control the timing from the loft, I want to change the system slightly. Seems like I have 2 broad options.
1) new wizz bang smart system like honeywell evohome - total cost about £600
2) swap out the thermostat with a programmable one, something like honeywell t4h110a1021 - cost about £60
As can be seen, thermostat has 4 cables, earth, break on temp rise, spare terminal, common. I’m a little confused by the blue wire on the spare terminal, as in the loft only 3 wires arrive (on the left hand side of the wiring picture). Is it possible that the thermostat also takes power directly from a separate mains feed, rather than the boiler?
There is 240v between earth & “break on temp rise”.
So, my question is, does it make sense to replace the thermostat with a basic programmable 230v thermostat, and then turn the boiler to “on 24 hours”?
The evohome system seems tempting, but will require me to get a plug socket installed in the loft, not the end of the world I guess. Ultimately I want to be able to set the heating to come on/off at different times depending on the day. Long term it would be be nice to go down the whole evohome setup, where you can control room temp individually with digital trv’s
Appreciate any thoughts, apologies that it’s all a bit rambling.
Paul