confused central heating and thermostats

[ballyclover]

Hi there.

Am really confused as to how this all works. My gas bills have been huge and i have been told to try turning down the radiators thermostats.

These are all set to number 3, max being 5. I have been told these will shut the heating off when each room reaches the temp, ( or the water supply to that radiator) whatever temp that relates to.

However as the moment all we do is turn the electronic themostat on the wall to say 20 degrees, and assumed that when that wall thermostat detected 20 degrees it would shut the heating down. So am confused as to what the actual radiators ones are controlling

would apprecaite any help

cheers

 

[ALEC1]

LOL Trvs dont actually turn down the boiler, just reduce the flow of hot water from the boiler which saves a bit of energy..

everyones bill is huge...but gas is still half the price of electricity...

 

[ballyclover]

right, so the thermostat on the radiators actually reduced the flow of water hence reducing the amount of water the boiler has to pump.

So what does the thermostat on the wall do when i set it to 20?

 

[D_Hailsham]

So what does the thermostat on the wall do when i set it to 20?

It (should) turn the boiler off when the room it is in reaches 20C.

Do you have a TRV on the radiator where the thermostat is located? If so, set the TRV to Max. If you don't, the TRV will control the room temperature, which may mean the thermostat never reaches the 20C set, so the boiler runs for ever. By setting the TRV to a higher temperature than the wall stat, it ensures that the wall stat controls the room temperature and turns the boiler off.

 

[ballyclover]

right, thank you. Yes there is a TRV on the radiator in the hallway about 4 foot away from the wall thermostat.


just a question but why wouldn't you just set all the TRVs to max, warming the house quicker and turning the boilder of faster?

Sorry if i am being thick

 

[D_Hailsham]

just a question but why wouldn't you just set all the TRVs to max, warming the house quicker and turning the boilder of faster?

Because TRVs don't work like that! A TRV is controlled by the room temperature, not the water temperature. The numbers on a TRV represent room temperature, so 1 may mean 13C and 6 may mean 28C. It varies from manufacturer to manufacturer and is only an indication of the actual temperature as environmental conditions vary from room to room.

When the room is cold, the TRV will be fully open, irrespective of what number is it on. When the room temperature is within approx 2C of the set temperature the TRV will start closing, which reduces the flow and therefore the rad output. If the room continued to heat up, the TRV would be fully closed at 2C above the set temperature.

In a correctly designed system the TRV will be fluctuating somewhere between fully open and closed, thus maintaining a steady room temperature; the rad may only feel warm. If the rad is going alternately hot and cold it usually means that the system has not been balanced correctly.

 

[Lower]

right, thank you. Yes there is a TRV on the radiator in the hallway about 4 foot away from the wall thermostat.

You need to set that the TRV in the hallway to maximum so that the wall thermostat does its job.

 

[D_Hailsham]

You need to set that the TRV in the hallway to maximum so that the wall thermostat does its job.

I think you will find that he's already been told that.

 

[ballyclover]

thank you guys, i understand it all now. with out the thermostats on the raditors they would just constantly be red hot untill the heat in the house reached the wall thermostat and knocked off the boiler.

using the TRVs they allow each room to reach temp independently then throttle back the amount of water passing through, thus reducing the amount of water the boiler has to heat

i think lol

thank you all

 

[Lower]

You need to set that the TRV in the hallway to maximum so that the wall thermostat does its job.

I think you will find that he's already been told that.

:doh: