TRV question

Joined
28 Mar 2010
Messages
120
Reaction score
1
Location
Argyll
Country
United Kingdom
I'm about to upgrade my central heating system, and will be fitting new TRV's to the existing radiators - I seem to remember reading somewhere, thats it better to leave one radiator with standard valves on it - presumably so the boiler can never be pumping against a dead head - ie with all TRV's closed?


Can anyone advise?
 
Sponsored Links
I'm about to upgrade my central heating system, and will be fitting new TRV's to the existing radiators - I seem to remember reading somewhere, thats it better to leave one radiator with standard valves on it - presumably so the boiler can never be pumping against a dead head - ie with all TRV's closed?
You need to have one rad without a TRV in the room where the wall mounted thermostat is located.

If you have a TRV on this rad one of two things will occur:

If the TRV is set to to lower temperature than the wall thermostat, the radiator will shut of when it reached the TRV set temperature so the wall thermostat will never reach temperature. Result is the boiler will run and run.

If the TRV is set to a higher temperature than the wall thermostat, the boiler will shut down when the wall thermostat reaches temperature, so the radiator will never reach the TRV set temperature.

You must have a wall thermostat to meet building regulations.

If you have TRVs on all rads but one, you also need an automatic bypass valve.
 
I'm about to upgrade my central heating system, and will be fitting new TRV's to the existing radiators - I seem to remember reading somewhere, thats it better to leave one radiator with standard valves on it - presumably so the boiler can never be pumping against a dead head - ie with all TRV's closed?
You need to have one rad without a TRV in the room where the wall mounted thermostat is located.

If you have a TRV on this rad one of two things will occur:

If the TRV is set to to lower temperature than the wall thermostat, the radiator will shut of when it reached the TRV set temperature so the wall thermostat will never reach temperature. Result is the boiler will run and run.

If the TRV is set to a higher temperature than the wall thermostat, the boiler will shut down when the wall thermostat reaches temperature, so the radiator will never reach the TRV set temperature.

You must have a wall thermostat to meet building regulations.

If you have TRVs on all rads but one, you also need an automatic bypass valve.

Thanks I thought as much !
I have a wall mounted room stat in the hallway, about 3m away from the hallway radiator, so I guess I just leave that radiator with standard valves? + auto bypass valve.
 
Sponsored Links
firebladerrw";p="1581814 said:
I have a wall mounted room stat in the hallway, about 3m away from the hallway radiator, so I guess I just leave that radiator with standard valves?
That's correct

+ auto bypass valve.
Some boilers have an auto bypass valve built into them, so you may not need to buy one.
But if you do, it connect the flow pipe immediately after the circulation pump to the return. This valve opens when TRVs close down.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top