Hot Water Problems

[Rowey1972]

Having had the system drained in the summer to remove a Rad, our central heating system has developed a fault. The boiler fires up and heats the Rads to a good temperature, but with the boiler switched to Heating & Hot Water, we are not getting any hot water.
We have to keep switching the electric switch on at the tank to heat the hot water.
I am told that the problem could be with the 3 port mid position valve, currently the valve 'arm' is situated to the left, and clicked into place, this provides the heating but no hot water, if I release this lever, it automatically moves itself to the right, and the hot water works but the heating does not. There does not appear to be any 'mid position'.
Does anybody have any ideas, I do not want to call a plumber unless absolutely necessary, cost and availability.

 

[gas4you]

What make of valve is it?

Usually the manual lever locks the valve into mid position but does not operate the microswitch.

I would say you need a new valve head as the ch microswitch has broken.

 

[Rowey1972]

Thank you for your reply, I will check the make of valve. If the head does need replacing, is it a big job, could I buy the part and do myself?