Heated towel rail
Hope you can help. We recently had our central heating flushed out and the plumber put in a new pump and valve and also had to make a low level drainage point cos there wasn't one.
The heated towel rail in the bathroom has ALWAYS been on but since we have had this work done it works fine when the water heating is on but when we put the central heating on it goes off completely and will not come on again until we drain it off again.
Please can anyone advise what the problem could be?
Not without being there and seeing the system and how it is controlled. If it has to be drained to get it working again, there is a functional problem that we cannot diagnose from here.
It could have a air bubble in it.
Note: I'm making some assumptions on how your system is set up.
My folks had air bubbles in there system and the HVac guy fixed it by using a small pump to drain all the water from the system into buckets and then re-fill it using the same water. I'm guessing that his piston hand pump pulled a vacuum in the process and that removed all of the air.
Air bubbles will fix themselves over time if you have a air trap in the system.