Boiler and rad issue

[eumac]

I have two problems, first, my wate cylinder is getting to hot/burning hot, the thermostat is not kicking in. How can I verify that this is the problem, any wiring diagram for a cylinder?
Second, air locked rads, i am using a gas burner to heat the rads, I have a total of x11 rads in the house, x4 rads are upstares, and these 4 are getting airlocked. When I blead the 4 they are ok, for about a day, and then get locked again. Is air getting into the system, upstares?, how can i isolate the problem, and how can i fix?

thanks in advance

 

[oilman]

my wate cylinder is getting to hot/burning hot, the thermostat is not kicking in. How can I verify that this is the problem?

Because your cylinder is getting to burning point.

 

[ChrisR]

Just put a new thermostat in - they're quite cheap.

Sounds like air is being drawn into your heating. Could be an original design fault, or something which has developed because of sludge build-up. Either way you need a heating engr to sort it out.