Radiator dial query - anyone else's not work on lower setting?

[Jasper76]

I have recently moved into a property and three of the existing radiator dials didn't work - they were not moveable and on constantly so I couldn't turn them off. I had a plumber come and drain the system to replace the three and now if I have the new dials on between 1-3 there is no heat only 4-5. I wondered what this might be so I have queried it and in the jest instance was told it would be rectified, but on second phone call the whole tone had changed and seemingly the problem can't be rectified without balancing the boiler or something? The only reason I am querying it is because the same plumber has told me 2 different things and I wondered if perhaps i had just been given rubbish dials? Anyone shed any light? Thanks

 

[oz-plumber]

Google ' Thermostatic radiator valves ' and the brand that you have installed.

It should give an explanation and the temperature range of the numbers on the dial.

 

[Jasper76]

The fact they have 1-5 on them is surely proof enough that the valves should come on between those numbers surely? they do turn between 1-3 but no hot water is teleased

 

[doitmyself]

The numbers on the radiator thermostats represent room temperatures, e.g 1=10C up to 6 = 28C The actual values will vary slightly depending on the make and model of thermostat. If the actual room temperature is below that set on the thermostat the thermostat will be open so heat is given off by the radiator when the required temperature is reached the stat will shut the radiator off.

The rads with the stats set to 1-3 are probably cold because the room is already up to temperature, ie over 10C to 18C. 4-5 represent a temperature of 20 to 23C so the rads will be hot if the room is below that temperature

Thermostatic radiator valves work much better of the flow through them is correct. This is achieved by balancing the system.

 

[oz-plumber]

That's probably because between 1-3 the temperature range is from 'off' to @ 20C
4 maybe 23C and 5 is completely open.
They are thermostatic heads and are controlled by the ambient room temperature.
That may be why the radiators are heating up on 4 or 5.

 

[rpm]

The fact they have 1-5 on them is surely proof enough that the valves should come on between those numbers surely? they do turn between 1-3 but no hot water is teleased

Did you do what oz suggested or did you just dismiss it because it wasn`t what you wanted to hear?

 

[solutions]

The fact they have 1-5 on them is surely proof enough that the valves should come on between those numbers surely? they do turn between 1-3 but no hot water is teleased

The valves are "thermostatic". They open and close based on the temperature in the room. The number's on the valve head (dial as you called it) correspond to approximate room temperatures. Each manufacturers are slightly different and they are not the most precise of devices but there is a good chance that numbers 1-3 on your valve heads are for a temperature your room is already at so the valve does its job and shuts hot flow to the radiator off.

 

[SimonG]

Wish I had a pound for everytime I have to explain to a customer that the valve isnt broken, its just doing its job. If the room is warm enough then they shut down.

 

[oz-plumber]

Wish I had a pound for everytime I have to explain to a customer that the valve isnt broken, its just doing its job.

Me too... I would be on double the money I am on now