the Icos has a drain off underneath it nr the isolation valve, isolate the the flow & return and place a bucket or something similar underneath and undo the drain cock, the pressure should drop to zero. When undoing the the 4 allen keys for the pump, undo the bottom 2 first and slowly undo the...
He' s right, if you remove the Central Heating Honeywell cover (soundslike the faulty one) and see 4 screws that attach the head to the body you need a plumber (or some bungs), if it has 2 screws, 1 at the top the other at the bottom you can unscrew those and remove the head. Turn the the...
pop your finger or thumb underneath the black arm and see if you can lift it out of the midpositon its stuck in or as stated above depress the black button on the side of the head and take the actuator off the valve body and check the body isn' t stuck.
The overheat stat doesn' t reset itself, you have to pop the switch back in yourself. The grey facia underneath the boiler has a hole in it, stick your finger in there and hey presto, there' s your OH stat.
You sure its gravity when you have a 3port valve also ??