embarrasingly basic thermostatic radiator valves question!

[Riz1]

Hi. I liked the principle if having thermostatic radiator vales fitted as i had the problem in my house that some rooms got stiflingly hot while others remained relatively cool/just right [different amounts of heat retention].

I also hoped this would help lower my fuel bills. A friend of the family builder duly fitted for me and i note he has fitted the Wickes TRVs.. I had simply assumed these would work [rather like a room thermostat] by you waiting til the room gets to the desired temp and then moving the dial until it just "clicks" off.

However these bascically have a dial numbered from 1 to 5 [and no discernable noise of them "shutting" now matter if i swung the dial from 1 extreme to the other]. I didnt patiently see if they work by seeing if a radiator got cooler [ie no hot feed in] if i turned the dial down to 1 or * but basically i don tknow how they work! Do i randomly try different numbers in each room until i manage to match a "number" with a comfirtable temp?

Do these valves simply work by restricting the amount of hot water that enters depending on how high a setting is selected [and if no how would that differ from the normal turn-screw valves that were on there?]

I appreciate helping me solve this simple but perplexing matter. Thanks

[Dave Plowman (News)]

They allow the full flow until up to temperature then shut it off.

It's not possible to mark them accurately in degrees, as they are to some extent influenced by positioning. So you'll just have to experiment a bit.

[Andy Hall]

Basically they have an expanding wax insert inside the valve head.

They do not click off, but gradually restrict the flow resulting in a cooling of the radiator. As the room cools, they open more and the radiator will become warmer.

All that you need to do is to adjust the setting of the TRV in each room until yu arrive at the temperature that you want.

You will find that the radiator will reach an equilibrium temperature and stay at that if the temperature outside remains the same. If it cools down outside, heat loss increases from the rooms and then the TRV will allow more water flow through the radiator to make it warmer.

You can get a situation if the room is warm that the TRVs will close off the flow completely.

In any case you should balance the radiators using the procedure in the FAQ. THis would involve opening the TRVs full and adjusting the lockshield valves to equalise temperature drops across the radiators. Although TRVs will deal with this issue in part, it is best to have reasonably equal starting conditons between rooms.

[BigWallop]

Try turning the hotter radiators down to three and the rest up to five to see if it makes a difference.

[EricP]

Very (VERY) crudely the temps are:

0 Off

• Frost

1 10C 2 15C 3 20C 4 25C 5 30C

The Plastic tower has an expanding substance in the form of a piston. When this heats up, it expands and pushes a plunger into the tap valve, reducing the water flow and turning off the water valve. It cools, opens and allows water to flow etc.

Crude but effective.