Sticking radiator valve.

[Nick]

This is on the only rad in our bathroom. Installed new in 2012 so not too ancient. One valve takes 3.5 turns on to off. The other will only go about 1.25 turns. Valves are identical so I'm presuming something is wrong. Rad never gets more than lukewarm. I've tried many times working it on-off-on-off-on etc with no effect. Also tried opening it with a bit more force than I would normally use and then tapping around the body with a small hammer. Again no effect. Probably answering my own Q but is the answer a drain down and replacement? Thanks, Nick.

[Bod]

Seeing as you'll probably need to drain down to fix it, you might just as well renew.

[Fredxxx]

The worst you can do is break the spindle if you apply too much force.

Only a partial drain is required. Turn the other radiators to OFF and drain down just sufficient that the bathroom radiator is above the water level.

I'd be tempted to replace both valves at the same time with a known make given the overall time and effort to do all this.

[DerbyBorn]

Could be a different make to the other and a coarser thread?

[F]