Pin below the TRV Valve

[Lk1980]

Hello
I have a slight issue with 2 of the radiators at home. When the heating starts in the morning, the radiators get nice and warm but after a while they cool down and doesn't warm up some times and they remain cold.

First I thought as the rads are about 11 years old, there might be a build up of sludge in them as a result they might not warm up.

After bleeding all the rads the water that came out was not dirty so not sure if there is any sludge in the system.

After a bit of reading on forums and YouTube etc... I discovered that the thick metal pin that sits below the trv valve has to come up in order for the rads to warm up. In my case, once it goes down it does not come up until the upper part of the trv is removed and the pin is pushed up with pliers.

I wanted to ask whether the pin is supposed to spring up immediately if pushed down or it comes depending on the temperature of the water in the system.

I did try and spray wd40 thinking it might loosen up a bit.

I don't want to spend unnecessary money on having power flush and change of rad trv valves.

Any help and advice will be most gratefully appreciated.

Cheers
Bineet

 

[terryplumb]

The pin moves up freely ,under spring pressure ,when the actuator head is removed. So you can press it down ,and it should pop up again.

 

[oldbuffer]

1. Don't pull the pins too hard. If they come out you will have a leak.
2. The pin should spring up immediately. Its the capsule in the removable valve head which senses the room (not water) temperature, expands and pushes the pin down to close the valve.
3. Don't use WD40. It's not meant as a lubricant, can attack rubber seals, and tends to go gummy. Silicone grease is a better alternative, but more difficult to apply.
4. It sounds as if you need to either free up the pins or replace the TRVs. It doesn't sound as if you need a power flush.

 

[Lk1980]

Thanks Oldbuffer & terryplumb. Thats great. I suppose, I will get the TRV changed.