central heating - thermostatic radiators *and* separate thermostat

[SecondaryBurnzzz]

So, we have a new house, and it has a new boiler, a wall mounted programmabe thermostat, and thermostatic radiators.
I actually can't work out how they work, and I'm usually pretty practical about these things. If I programme the temperature on the thermostat, do the radiators work to that temperature, or do they just do what their own thermostats tell them to do? we seem to be boiling hot all the time, and I have set the Thermostat to 19! Gah. Can you help?

The thermostat controls. The boiler going on and off.
Then each Rad has its own control.
If you are too hot i would turn the thermostat down by a degree and then observe which rooms are hotter and cooler and adjust the rrads until you are comfy.
We set our main therm at 18 and the ground floor rads on full 5 stars and then all the rads upstairs are off.

Depends on the system you've got.

The simplest system would be TRVs (thermal valves) on the radiators and a wall thermostat that just measures the temperature at that one point - if it drops below the temperature you set wherever the panel is, the heating comes on regardless of how hot it is elsewhere in the house, you then need to turn down the valves in the hot rooms and turn up the valves in the cold rooms to heat each room as appropriate.

More sophisticated systems have a connected sensor in the valve on each radiator, so if any room drops below a desired temperature the heating comes on but the valves control which rooms get heated.

With either system you than have a timer that determines the times the heating is able to be active.

If you could tell us the make / any models and give an idea of the layout it may be possible to be more specific.

Thanks both, it's a Vaillant boiler, pretty standard radiators with turnable valves that go from red to blue (no brand name) and thermostat is a Salus rt500rf.

What you've both said makes total sense though which is great so thanks!

the room stat should be in the room that

1. has no TRV

2. has been balanced so that it heats up slower than all the other rooms

3. has no other source of heat in it

4. is the room you spend most of your time in, therefore the room where a comfortable temperature is most important

In the old days, people used to put the stat in the hall. Most people spend very little time in the hall.

(1) and (2) you can easily fix in necessary.

Look for the brand of TRV that you have and buy at least one spare. Keep the extra cap carefully.

Thanks Piglet the room thermostat is in the hall, but with a radiator with no TRV, it does come off of the all though, so I could move it around.
Its a 1910 house with very large rooms and high ceilings, and despite having double glazed windows seems to cool down quite quickly.
I have no idea what the TRVs should be set to either, hot is +5 cold is - with one symbol in the middle, does that mean off, or does that mean 'whatever the thermostat default temp'
I'm sure I'm overthinking this - sorry!

round about 3 is about right.

You need to leave the heat on at your chosen setting for an hour or two, with the door shut and the curtains closed, then walk into it, sit down for ten minutes or more, and see how comfortable it feels.

If you walk in from a cold room it will feel warm; from a warm room it will feel cold, so you have to sit quietly for a bit. A room that you are constantly running around in will make you feel warmer. Wear some clothes.

BTW, when your Salus goes wrong, get a Honeywell.

As a sanity check, don't move anything yet, particularly not the thermostat. Your system may well have been set up with it where it is and it needs to be in a central space which is not subject to sources of heat that do NOT emanate from a radiator, hence the hall.

It should be on an internal wall, away from the radiator and outside doors and 1.5 metres high. The hall radiator should not have a thermostat, or the stat must be set at maximum.

Central heating is designed to heat different rooms to different temperatures, so all doors must be kept closed. The radiators will be sized to reflect the different temperatures required.
The hall will be designed to be about 17/18° maximum, this is done to minimize heat loss when the front door is opened, and so that the house doesn't feel like an oven when you come in. Other room's radiators will be sized accordingly.

Set the wallstat to 16° and all of the radiator thermostats to maximum and over a few days if needed, assess the comfort levels everywhere.

I suggest your target temps could be,
Bathrooms 23
Lounge 21
Dining Room 19/20
Bedrooms 17 to 19
Landing 17
Hall as per wall stat ;-)
Adjust the stat to achieve the best compromise for you, in older properties a setting of only 15° might be sufficient, but why do you need a warm hall?

Take your time over the above, aim to get things a bit too hot, then use the rad stats to bring down individual room temperatures.

A good reason for not having the stat in the lounge is that a few people, a large TV and a sound system constitute a heat source that isn't a radiator and could easily result in the lounge having to be uncomfortably hot in order to keep the rest of the house warm, particularly if it has a sunny aspect.

Put the room stat on a comfort temperature, most opt for 21, your trv's will regulate the temperature of each room, 2 =16/18 3=19/21 and so on, off the top of my head, again most opt for 3 down stairs and 2 /3 for bedrooms.
If your house is 1910, I don't suppose you have a cavity that can be filled, your high ceilings will attribute to the room cooling as the warmth will be up there as heat rises, my 2p worth

Lol you know nothing so why advise lol

Thanks everyone- that’s really helpful. 19 would be my optimum temp and I like a cold bedroom (child of the 70’s). I had thought that I’d reset the stat to 19 but I often look at it has and it crept up to 23. Will have to look at the programmes again.

You’ve been really helpful so thanks again

Salus programmable room stats, and presumably others, can be a real faff to set up!
I had one until recently and found that the only reliable way to deal with it was to take it down, go to a quiet room for half an hour and concentrate. Go through every setpoint change in every day very methodically. This will usually involve swearing ;-)

On another subject, if you have a Combi boiler (hot water goes straight to the taps, no hot water tank) Set the boiler temperature to 57°. This will allow it to be in it's most efficient, condensing mode. Better to start the heating earlier than run the boiler hotter. You MIGHT have to turn the boiler up if it gets really cold out though.