Central heating - no thermostat ?

[Aviz]

Just spent an hour rooting round the new house for a room thermostat. I'm pretty confident I can say there isn't one !!

All rooms apart from bathrooms have thermostatic radiator valves, but I Can't believe there's no central room stat. There's a relatively new boiler in the garage with what I assume is some sort of frosts stat next to it which is set to 2 degrees. There's a pretty standard heating/water timer in the downstairs cloakroom.

Is this common - not to have a room stat. Seems like it'll mean the boiler is firing all the time, and the towel rads in the bathrooms will be on all the time, If the heating is on ? Sounds expensive

Also.. Anyone an idea what a "water heater" switch might be for in the kitchen? I have no idea !! The immersion heater switch is upstairs next to the cylinder .

Cheers

Andy

[m4ckg]

I've come across a few houses that dont have room stats, basicaly the boiler works of the temp of the water flowing through the boiler rather than the temp of the room, not cost effective really so I'd suggest a wireless programable room stat. ( think thats right anyway )

[Road2Ruin]

If it is a new fully modulating boiler I would say it makes very litle difference. The boiler will reduce the heat depending on the temp of the water returning to it. So if the TRVs are doing their job then it wouldn't be too bad.

[Aviz]

Road2Ruin said:

If it is a new fully modulating boiler I would say it makes very litle difference. The boiler will reduce the heat depending on the temp of the water returning to it. So if the TRVs are doing their job then it wouldn't be too bad.

Thanks. Am i right in thinking that the non-TRV rads (towel rails) will constantly be on then ?

[Road2Ruin]

They would, but the water temp to those would be reduced also. You usually find bathroon rads have no TRV but I cant remember why now.

[GreenDog]

Road2Ruin said:

They would, but the water temp to those would be reduced also. You usually find bathroon rads have no TRV but I cant remember why now.

I was told by a BG engineer that often the bathroom radiator is used as bypass valve, so if all the other rads in the house are switched off water can still circulate in the system. He said a proper bypass should really be fitted somewhere in the system however. I only found this out because I had taken the bathroom rad off whilst tiling and when I switched the heatin on the boiler was making some funny noises - turns out that if I'd left the system on much longer I'd have blown the back off it

[james_tigerwoods]

We're looking at a house that doesn't have one and I was admittedly a little confused about this too. It's a new combi boiler with a mechanical 24 hour timer (which sucks) and no apparent thermostat - all the rads have thermo valves though.

Is there any way to retrofit a thermostat?

[SimonV8ster]

I had a new combi boiler and central heating system installed 4/5 years ago. It had a stat which I thought odd. All rads have a control valve on them so I thought I didn't need a room stat as I could control the temperature in each rad ?

[A Scotsman]

SimonV8ster said:

I had a new combi boiler and central heating system installed 4/5 years ago. It had a stat which I thought odd. All rads have a control valve on them so I thought I didn't need a room stat as I could control the temperature in each rad ?

That's right. Unless you own a particularly large house then individual radiator thermostats coupled with a thermostat on the boiler itself is fine. You should also have a thermostat on your hot water tank.

[was8v]

james_tigerwoods said:

We're looking at a house that doesn't have one and I was admittedly a little confused about this too. It's a new combi boiler with a mechanical 24 hour timer (which sucks) and no apparent thermostat - all the rads have thermo valves though.

Is there any way to retrofit a thermostat?

Depends on the boiler. I retrofitted one to ours, an old SIME boiler, it had the connections for it.

If you do this then make sure the system is properly balanced - might be obvious but when the room with the stat gets to temp the whole system goes off, perhaps leaving some rooms cold.

If the system hasn't ever had a room stat then its unlikely to be well balanced - when just using TRVs it doesn't matter so much.

[james_tigerwoods]

I appreciate this might be an idiot question, but what is the best way to "manage" my house with TRVs and no thermostat?

[Aviz]

Thanks all for your input. I have 15 Rads, so may be worth looking at fitting a room stat. I can sort of understand how the current system works now

[Road2Ruin]

james_tigerwoods said:

I appreciate this might be an idiot question, but what is the best way to "manage" my house with TRVs and no thermostat?

An idiot question? From you? Never

[james_tigerwoods]

Road2Ruin said:

An idiot question? From you? Never

'tard

[R1 CKY]

Its against building regs to install a heating system without a room thermostat.

Even with TRVs controlling the rooms individually, the heating pump will be running the whole time the heating is turned on. So if most of the TRVs close and you only have on bathroom rad on, you will shorten the life of the pump. Also it will be continually losing heat through the pipework, therefore the boiler firing more than it should.

Thermostats are very easy to add to a system. Most combi boilers will have a link on the circuit board which you can wire a stat into.

Conventional boilers will require the wiring to be altered within the wiring centre.

Plenty of wireless stats on the market, that can be fitted in less than an hour if you are handy with wiring.

With regards to the Water Heater Switch in the kitchen, some properties have the wired before the switch in the airing cupboard for the immersion, simply to save you walking upstairs to turn it on.

[james_tigerwoods]

Thanks R1CKY - if we ever get in, I'll look up the model of boiler and see whether it can be fitted...

[missdiane]

We have a combi boiler with timer, with no house thermostat, we do have adjustables on the radiators.
Gas costs us £50 a month for the yearly use, we run a warm house and have never found it to be a problem not having a thermostat
When the rads get hot enough they cool down and we only have about 3 of the rads on full in coldest of winter
Not sure if that helps or not

[R1 CKY]

By all means, you can control a house quite comfortably using just TRVs.

But there is always the chance that the boiler will fire up again once the water temperature in the system drops, which it will because the pump will still be running and losing heat through the pipework.

When a room stat becomes satisfied, the heating is switched off, so the pump isn't running and not losing as much heat.

Also, if you do decide to install a stat. It should be sited in the area with the most air changes (usually the downstairs hallway), out of direct sunlight, approx 1.5m from the floor, not too close to a heat source, not in a room with a secondary heat source and the room in which it is sited should not have a TRV on it.

[Aviz]

R1 CKY said:

Its against building regs to install a heating system without a room thermostat.

Even with TRVs controlling the rooms individually, the heating pump will be running the whole time the heating is turned on. So if most of the TRVs close and you only have on bathroom rad on, you will shorten the life of the pump. Also it will be continually losing heat through the pipework, therefore the boiler firing more than it should.

Thermostats are very easy to add to a system. Most combi boilers will have a link on the circuit board which you can wire a stat into.

Conventional boilers will require the wiring to be altered within the wiring centre.

Plenty of wireless stats on the market, that can be fitted in less than an hour if you are handy with wiring.

With regards to the Water Heater Switch in the kitchen, some properties have the wired before the switch in the airing cupboard for the immersion, simply to save you walking upstairs to turn it on.

Thanks R1 CKY, i think you are probably spot on with the water heater switch, and that may explain why my Dad said he couldn;t get the immersion to work from the switch upstairs (probably swicthed off downstairs). You also raise my original concerns of the water circulating, even when not required.

Mine is not a combi, but i'm pretty handy with wiring (colour blindness means i usually have an assistant though ) and I'm sure it's not difficult to fit a room stat into the system.

cheers

Andy

[R1 CKY]

Very simple to wire up, effectively a switch between the Timer and the 3 port/2 port valve.