Second thermostat in parallel with the first one.

[ericmark]

I can't see a problem, I have done it before, but with a gas boiler, now using oil. But just in case something I have not considered, asking the question.

The main problem is the cats, who will claw at the carpet if a door is closed, so we have a door stop to stop the raising butt hinges fully closing the living room door, the hall radiator is near front door, with a programmable TRV head, and the wall thermostat other end of hall, about as central to whole house as one can get, two doors between it and the radiator, hard wired, but the distance means it can over shoot.

Setting at 0.5°C raise every two hours has before doors stopped from closing fully worked, I do not like wireless, already had problems with previous house where the thermostat and base lost contact with each other, but should not really be a problem if using two thermostats, as if one fails other will still work.

So tomorrow fitting a wireless Wiser thermostat in parallel with the Nest Gen 3 wired thermostat, putting the Wiser head in the living room, to keep heating running if living rooms cools faster than the hall. Approx shape of living room and hall showing radiators and doors, plus stairs and windows. The boiler is in the flat under main house, only two wires between boiler and main house, which power and take signals from the Nest Gen 3. This also controls DHW if required when CH not running, but C Plan so can't turn DHW off, and now use solar in summer for DHW, so second thermostat for CH only.

Can anyone see any problems?

 

[ericmark]

Got, fitted, but at moment still disconnected, I had problems getting it to connect to internet, so gave up for the night, then found all connected and working, so tomorrow will pop the wire in.

 

[big-all]

so iff you have 2 requiring heat and one is in a freezing cold area that will never stop requiring heat
would it not be better to just have one but placed at the most important area ??
unless you have zoned areas but even that will be governed by the lowest common denominator or have i misunderstood as usual

 

[ericmark]

The problem is the hall cools too slowly. It is central to the house, so for heating seems the best place, but living room would get cold, before hall, but since an open fire in living room, that is not where a wall thermostat should go.

Rooms can't over heat the TRV's stop that, so a wall thermostat calling for heat when not required will cause boiler to cycle, but that is all.

At the moment I was having a problem getting the Wiser to see the wall thermostat, so left it disconnected, with idea of trying again today, it now has connected, to wall thermostat and internet, so latter today I will reconnect it.

Main problem was although Nest said it worked with Energenie TRV heads, it didn't, so next move is swap my wife's bedroom eQ-3 TRV head for a Wiser TRV head so her room when it needs heat can turn the boiler on. My room naturally warmer than hers, so no need to have my eQ-3 linked to the boiler other than by water.

Nest Gen 3 has proved to be rather useless, I got it as don't want to rely on a wireless system, central heating not working due to discharged batteries is not good. But since the wiser is a second parallel system, if the batteries go flat, heating may not work as well, but it will still work.

 

[ericmark]

I can hardly believe it, problem was micro switch sticking in the motorised valve, I was looking for some thing I had done wrong. The Wiser is free standing, so nothing wrong with my wife taking it into her bedroom if bedroom cold, but I will see how it goes first.

Now day 3 so not really had a chance to really test it, however clearly have a problem with over shoot. but the TRV report does not match the free standing thermostat report, it is complicated by having two radiators in the same room, so two TRV's one Energenie Mihome the other Kasa the latter gives the report, and I need to now experiment with the settings and the placement of the free standing thermostat.

We get diagrams but these don't really help with modern double glazing, a T shaped room and two large radiators, I really don't have a clue as to air flow, door on raising butt hinges so always nearly closed, but a door stop prevents it fully closing or the cats will scratch at the carpet.

When garage under the living room turned into a flat loads of insulation it seems was added, but above room ceiling to bedroom floor an empty void.

The problem of the hall taking too long to cool has now been redressed, just need to do some fine tuning.