Removing Danfoss TRV cover??

[HaplessHubby]

I am having a heck of a time trying to get the plastic control knob off an older-style Danfoss thermostatic radiator valve in order to gain access to the stuck valve pin. It does not seem to unscrew and there is no (obvious) mechanism to allow removal. I'm sure there is an easy trick to do this but sadly I don't know it! My Danfoss radiator valves are around 15 years old. Can anyone help. Thanks in advance for any advice you can offer

 

[leakydave]

Photo would help...

 

[Phill Peck]

The knurled black plastic bit where it attaches to the brass body will twist.
It may have a retaining plastic clip that needs to be popped out with a screwdriver to allow it to twist.

This is of course an educated guess based on what TRVs I think u have, as suggested a picture would help

 

[HaplessHubby]

Many thanks for prompt response.
I'll get a picture posted when I get back to house.

 

[HaplessHubby]

Please find attached photo of the TRV in question.

 

[Phill Peck]

Tbh I'm not sure I've ever seen that particular head but u would be having a look at the small square facing up on the knurled black bit.
See if that will pop/prize out.
I would then expect the knurled bit to twist.

Btw u don't always have to remove the head to unstick a pin.
Set valve to max turn htg on and hit the valve with hammer. Not so hard that u are swinging at it but a couple of short blows and see if the heat start to comes through.

 

[Aquaheat]

On these there was generally a small grub screw located on the lower half of the valve. It looks to be facing up on yours but is hard to tell as picture isn't very clear.

Undo grub screw and head should pull off, might Nedd to give it a wiggle and a bit of oomph as they can be quite tight.

Jon.

 

[HaplessHubby]

Problem solved!
Many thanks to all who contributed