Single Zone - Two Thermostats?

[imroberts]

My system comprises of a Glow Worm Ultimate 30C boiler with a Climapro2 RF Thermostat.

The central heating is all on a single zone including an office extension - despite being newer the office doesn't seem to heat up as quickly, or retain heat as well as the rest of the house.

Ideally I'd have the office on a separate zone so I can have different schedules and temperatures for the main house and my office, however the work involved in doing this isn't feasible right now.

As such I'm looking at other options - I really like the look of the Evohome system where any thermostat or TRV will trigger the boiler to figure, but I'd probably want to fit TRVs throughout the entire house if I went with Evohome, which would cost a fortune so I'm trying to resist the temptation.

Is it possible simply to add a second thermostat in the office, such that if either that or the one for the main house calls for heat, the boiler will come on, and I can rely on the existing manual TRVs to control which rooms actually get heated?

 

[dilalio]

Yes. As in you can have more than 1 switch on a circuit... Anything that reconnects the angry pixies.

 

[ianmcd]

nope wont work without zone valves being added

 

[fezster]

Is it possible simply to add a second thermostat in the office, such that if either that or the one for the main house calls for heat, the boiler will come on, and I can rely on the existing manual TRVs to control which rooms actually get heated?

It's possible, but if the office is always the last to heat up, it'd be the same as just having a single thermostat in the office.

Without zoning the actual pipework, the heating will stay on everywhere until the office reaches the stat temperature. The manual TRV's will help to stop the other rooms overheating - but they are not as precise or as quick to act as a digital room stat.

 

[imroberts]

It's possible, but if the office is always the last to heat up, it'd be the same as just having a single thermostat in the office.

Without zoning the actual pipework, the heating will stay on everywhere until the office reaches the stat temperature. The manual TRV's will help to stop the other rooms overheating - but they are not as precise or as quick to act as a digital room stat.

I guess that's true - the main issue with having a single thermostat in the office is I don't need this heated in the evenings or at the weekend - which is why I essentially just want something in the office that can be programmed for office hours to trigger the boiler when the rest of the house is potentially already up to temperature.

I spent some time looking at Tado last night and that looks like it'd probably do what I want.

If I got the standard wireless starter kit I think I could have the "standard" room stat in the lounge with a similar programme to now, and simply add a TRV in the office which I could program to suit my working pattern? And either of these would trigger the boiler to come on?

 

[dilalio]

Also look at evohome.

 

[ericmark]

Yes I had two thermostats in parallel and it worked well.

The thing to remember is the wall thermostat is there to stop cycling not to control temperature, it switches boiler off when not required, but it will required matching of the wall thermostat program and the TRV head program.

The TRV needs to be set slightly lower than wall thermostat I have found in my house, basic fact the wall thermostat is higher, and heat raises, will vary home to home, but in theory if you had a TRV and wall thermostat in every room, the TRV will stop room over heating if a wall thermostat in another room is on, so TRV sets highest temperature and wall thermostat the lowest temperature.

So this pair in every room would allow complete independent control of every room, in practice likely two is all that is required to keep boiler running when required, and only these in every room. So the TRV head costs around £10 or £15 with blue tooth and the wall thermostat around £35 it is of course important both are programmable. You could go for likes of Hive, but the TRV heads are far more expensive jumping to around £60 for TRV heads which link to the wall thermostat.

You may even get away with one wall thermostat, if the wall thermostat drops just 0.5°C an hour before the TRV changes temperature then it goes up again 0.5°C as it changes this will likely ensure boiler is running when temperature changes. The wall thermostat shown has 6 temperatures per day, that limits how many times it can drop and raise 0.5°C.

 

[ericmark]

nope wont work without zone valves being added

Yes it will, I have done in, proof of pudding in the eating, did it with mothers house due to sun in bay windows changing to balance of heating front and rear of house, I had one thermostat in hall, not ideal, and one in kitchen also not ideal, but as a pair in parallel they worked well. OK I suppose you can say a TRV is a zone valve, but that is not what most of us consider as being a zone valve.

 

[ianmcd]

Yes it will, I have done in, proof of pudding in the eating, did it with mothers house due to sun in bay windows changing to balance of heating front and rear of house, I had one thermostat in hall, not ideal, and one in kitchen also not ideal, but as a pair in parallel they worked well. OK I suppose you can say a TRV is a zone valve, but that is not what most of us consider as being a zone valve.

*******s, with his set up he would have to manually turn off all TRVs when he only wanted the office to heat up

 

[ericmark]

*******s, with his set up he would have to manually turn off all TRVs when he only wanted the office to heat up

Why? If the TRV is set to change temperature it does not need any manual intervention once set, it will change at programmed time.

It may be better with a non programmable in room with thermostat, as they tend to work over a larger temperature range than the programmable type, the tower one I have in my draw after it was removed to fit eQ-3 starts to pass air at 2.25 and is fully open at 3, and I used this to my advantage at mothers house in the hall which also had a non programmable wall thermostat, set to 2.25 on TRV and 20°C on wall thermostat, when front door was opened clearly hall got very cold, getting my mother in to house with her wheel chair.

On closing the door TRV was open wide and wall thermostat was on, so radiator would heat up quickly, and raise hall temperature to around 17°C at which point it would start closing, so gradually as the last 2°C was achieved the radiator would be cooling so by time it hit 19°C to turn off wall thermostat the boiler had been running for an hour, so all other rooms also had chance to warm up.

I will admit setting lock shield, TRV, and wall thermostat to complement each other took some time, with a little tweak each day for first week or so, but once set it simply worked.

The only problem is once a year fitting 18 x AA batteries, my wall thermostat here is mains powered with battery back-up so only have to change batteries in the TRV heads, in real terms I do living room and hall as a matter of course once a year, the rest I wait until reports as flat, normally just shy of every two years.

As said I know it works, as I have done it. Now in two houses. So if his office in not warm enough, then he just turns down the lock shield or TRV in room with wall thermostat, or turns wall thermostat up.

Where ever the wall thermostat is, that is the critical room, that room controls how long the boiler runs for, the idea is to have that critical room keep the boiler running for as long as it can without causing the boiler to cycle assuming a modulating boiler.

 

[ianmcd]

Why? If the TRV is set to change temperature it does not need any manual intervention once set, it will change at programmed time.

It may be better with a non programmable in room with thermostat, as they tend to work over a larger temperature range than the programmable type, the tower one I have in my draw after it was removed to fit eQ-3 starts to pass air at 2.25 and is fully open at 3, and I used this to my advantage at mothers house in the hall which also had a non programmable wall thermostat, set to 2.25 on TRV and 20°C on wall thermostat, when front door was opened clearly hall got very cold, getting my mother in to house with her wheel chair.

On closing the door TRV was open wide and wall thermostat was on, so radiator would heat up quickly, and raise hall temperature to around 17°C at which point it would start closing, so gradually as the last 2°C was achieved the radiator would be cooling so by time it hit 19°C to turn off wall thermostat the boiler had been running for an hour, so all other rooms also had chance to warm up.

I will admit setting lock shield, TRV, and wall thermostat to complement each other took some time, with a little tweak each day for first week or so, but once set it simply worked.

The only problem is once a year fitting 18 x AA batteries, my wall thermostat here is mains powered with battery back-up so only have to change batteries in the TRV heads, in real terms I do living room and hall as a matter of course once a year, the rest I wait until reports as flat, normally just shy of every two years.

As said I know it works, as I have done it. Now in two houses. So if his office in not warm enough, then he just turns down the lock shield or TRV in room with wall thermostat, or turns wall thermostat up.

Where ever the wall thermostat is, that is the critical room, that room controls how long the boiler runs for, the idea is to have that critical room keep the boiler running for as long as it can without causing the boiler to cycle assuming a modulating boiler.

because he has manual TRVs read the feckin post

 

[ericmark]

because he has manual TRVs read the feckin post

yes but he says

I really like the look of the Evohome system

so clearly looking at idea of using some type of electronic type.
I have made an error, and I will admit it. and show I was wrong, you can't connect two thermostats in parallel, I have made an error, not sure on the EPH system, I know EPH can be set to master/slave, but not sure if this ebus will work with opentherm? However the same applies to EvoHome unless this boiler will work with opentherm it is a non starter.

However the eQ-3 or i-terrier

can still help, if you reduce the temperature setting on the TRV in room with the wall thermostat it will cause the boiler to run longer, as will closing the lock shield valves.

Personally I would in this case not fit a TRV in room with thermostat, I would simply close the lock shield valve until all other rooms are warm enough, and only fit eQ-3 to other rooms, not room with thermostat.

Sorry did make an error, as did @dilalio @ianmcd @fezster all who like me jumped to the conclusion it was an on/off thermostat not one connected to ebus.