Belmont rad valve leaking

[JimDowson]

Belmont type rad valve (old) leaking slightly in my bedroom, round the top, I've never had to change any of my valve before or fix them, I believe i need a new oring (s) for these type of valves.... as they're unlike the packing gland (ptfe) standard rad valves, do i need to drain down to undo/get to the o-rings?.....??

Have never worked on 1 before, so any advice would be great before I start!! They all happen at once!

 

[clf-gas]

Seeing as you want to add inhibitor to this system then why not, drain off and remove rad valve, inject inhibitor repair and replace valve, refill system and run to circulate.

 

[JimDowson]

Good idea!

System is full of water now though .... took ages to re-fill Was thinking of draining a bucket or so and then adding inhibitor then topping up as necessary to get back to 1.5 bar.

ARe these valves hard to replace o rings?

 

[Boilerman2]

There are two types of O ring, Red & Green, One is for the Old Belmont Valve (Grey Knob) and the other is for the newer version, I'm sorry I can't remember which is which, I do know that the valve is a nightmare to fix and only for the very brave!!

You have to turn the valve fully on, then remove the knob, undo the brass packing nut, using a spanner on the spindle, unscrew the spindle out of the valve, the spindle will leave the valve seat in place inside the body, (the pressure of water holds it in place!!!,) repalce the O ring on the spindle and NOW THE SCARY BIT... you have to re-insert the spindle into the valve and screw it back down, DO NOT PUSH OR FORCE TOO HARD or you will overcome the pressure of water holding the seat, causing it to drop which will result in a system full of water to pour out of the valve, and leaving you with a total disaster. BEST TO FIT A NEW VALVE