Plumber explains what radiator numbers really mean and why you should 'leave it' at 3

[Harry Bloomfield]

Driver and steersman, standard way to move large loads, and it works well.

OK, and who is in charge of the vehicle, and who simply does as he is told by the driver?

 

[denso13]

it says a thermostat should not be used in a room with a thermostat

No it doesn't, TRV's and room stats are not the same thing.

 

[ericmark]

TRV's and room stats are not the same thing.

Pardon, are you sure? I thought the T in TRV stands for thermostatic?

 

[denso13]

Pardon, are you sure? I thought the T in TRV stands for thermostatic?

Yes, I'm sure.

 

[Harry Bloomfield]

Pardon, are you sure? I thought the T in TRV stands for thermostatic?

What's in a name? I repeat - a normal TRV fitted radiator, limits or restricts the temperature in the room. A room thermostat, is there to call for heat, when the temperature falls too low. As such, the two cannot work effectively if co-located, in the same heated space.

 

[ericmark]

A thermostat or sensor

will cause something to happen when it reaches a set temperature, it does not matter what it does it could cause water to flow, or a valve to open/close, or a boiler to fire, it is still a thermostat.

they are all thermostats. And today there are so many ways to thermostatically control a room temperature, you do need to qualify what you are talking about, I do not I admit I do not cover all bases when I call it a wall thermostat, as I know mine can also be used freestanding, and it can both connect direct to the hub, or to a TRV head, and the first two shown are designed to connect to a TRV head.

If one does not specify what type. Then one has to expect people to ignore it, as it does not make sense.

 

[denso13]

If one does not specify what type.

I've got six in my bathroom. Beats your two in a room.

 

[Harry Bloomfield]

A thermostat or sensor

will cause something to happen when it reaches a set temperature,

Correct Eric, but the point you seem oblivious of, is that the room stat switches on when it gets cold, the TRV switches off when it gets too warm in the room.

 

[ericmark]

Correct Eric, but the point you seem oblivious of, is that the room stat switches on when it gets cold, the TRV switches off when it gets too warm in the room.

I can see the room stat switches on when it gets cold, and the TRV switches down when it gets too warm in the room. There is a big difference between on/off and up/down.

The problem is if one stays on, after the TRV has closed. This is the

'fighting', to be in charge of the heating,

Harry talks about.

We need to look at the circulation, the TRV is naturally colder than the Wall Thermostat WT, so if both set to same temperature the WT will turn off before the TRV fully closes. Specially since TRV is often against an outside wall and the wall thermostat needs to be on an inside wall.

There are clearly times when this will not work, due to the room selected, I have never worked out, how the hall can be used as a sample room, as to place the wall thermostat on the opposite wall to the radiator and TRV and to get the flow of air with a staircase coming off the area is near impossible, so to fit a TRV and wall thermostat in the hall, is going to present a lot of problems trying to set it up, so Harry's statement likely true in that case.

 

[Harry Bloomfield]

I can see the room stat switches on when it gets cold, and the TRV switches down when it gets too warm in the room. There is a big difference between on/off and up/down.

The point is still going straight over your head.....

For the room stat to click off, the room temperature has to exceed it's set point, which means the TRV has to be set higher than the stat. IF the TRV is set higher, then the temperature will be controlled by the stat, the TRV cannot operate to ever close, and it therefore it has no purpose in life.

I have never worked out, how the hall can be used as a sample room,

Why not? It is as representative as anywhere else in the house. The installer, decades ago, designed and wired it to be in the living room, I insisted, it should go in the hall, because when the gas fire was lit, the CH would go off, leaving the rest of the place cold. I now have two wired stat positions blanked off, and a wireless stat running the system.

The stat is set to 18C, which is the temperature in the hall, other rooms, are warmer, their temperatures set by their individual TRV's, and all just works, sweet as a nut, with boiler only rarely firing.