any way to fix sticky TRV?

Nom_Deplume

One of our Danfoss TRVs sticks in a closed position and will not open to allow hot water flow when the thermostatic controller calls for it (e.g. even if I turn it up beyond 5).



I can take the thermostatic controller off and move the pin in and out a few times, and this will cause water to flow again, but only for a few days. I've lubricated the pin from the outside, but I believe the problem is not that the pin itself sticks, but rather the mechanism inside the valve body where the lubricant does not easily reach.



Is there any fix short of draining the system and replacing the valve? Just to emphasize, the detachable plastic thermostatic thingy works just fine, the sticking is in the metal valve.