How do i repressurise boiler

Sq

i watched a couple of videos but not seen one that mirrors my system, it used to work with some rads partly warm and 1 or 2 hot while the others stayed cold even after bleeding the rads, but i noticed after turning on the thermostat yesterday, i could get hot water but no central heating, i also couldn't hear the "boiling sound" from the external boiler.

Lenar3556

You could have few things going on there and a plumbing contractor will be able to get a handle on it more efficiently than you will.

But, to answer your question - there appears to be an automatic filling valve in the bottom photo with the pressure gauge pointing to zero, which would suggest the system pressure is low. The handle is broken off the filling valve so you will need to pair or pliers on the spindle to open it manually - it’s the spindle on the inside (pointing away from the cylinder) that you would need to open by turning anticlockwise. You should then hear water flowing through the valve. Fill until the gauge is at about 1 bar.

John.G

You might also have to get the ST pump running, just open a cold tap enough to get the pump running. Also, (latch) open the two motorized zone valves before refilling and unlatch them when finished.