Manual rad valve: always on full blast

[vulcancontinental]

Then do as I explained earlier.
Next cold weather turn the big rad off then open the valve a quarter of one rotation.
Ignore the temperature at the top of the radiator, your body is the best sensor you have not your hand at the hottest section.
After an hour if you're warm enough that's it, if not open the valve a quarter turn more. repeat as necessary.

My understanding is that the manual valve is either on or off.
But your instructions suggest that changing the setting of the manual valve will affect the rad temp.

Things are never clear cut are they?

No, the radiator temperature will not alter at the top of the radiator because the temperature of the water entering the radiator will remain the same and naturally gravitate to the top.

The amount of hot water entering the radiator will be reduced however and that means less of the total radiator area will be as hot and so will emit less heat.

The object of the exercise is to warm the room, the temperature of the radiator is only a factor. Forget the radiator temp. Starting from the valve closed position open the valve a quarter of one rotation in the cold weather and wait; if you're warm enough job done. If you're not warm enough open it a quarter turn more. Repeat as necessary.

 

[gasafengineer]

As has been noticed with regard to turn-down ratio of wheel head , response curve is highly non-linear due to large reductions in water flow rate resulting in only a small reduction in heat output rates .....................in other words valve stem movement (turn down ratio) will play a critical part regards 'modulation of water flow rate'................cheapo type rad valves with high ratio stem movement will be a PITA to modulate rate of flow hence the reason TRVs are used...............will await the nonsense posting with regard to the WC fans amoung us.

 

[monoxide62]

Can see this thread ending up with who has the largest Kahunas.

 

[bengasman]

Kahunas? Has central heating become some sort of witchcraft?

 

[monoxide62]

Kahunas? Has central heating become some sort of witchcraft?

Balls.

 

[bengasman]

Kahunas? Has central heating become some sort of witchcraft?

Balls.

In what language?

 

[Charnwood]

I think he means cohones; "Spanish slang for testicles, balls. Normally said in reference to someone's bravery or guts."

Kahunas means big boobies.

 

[dal5band]

Mike004, I think the answer is that you need a proper control system if you want to control the temperature in your lounge. If you insist on using the manual valve frequently you will soon wear out the gland seal in the valve head and it will start leaking past the stem.