Bung System - Advice Needed

[zakaryfaithfull]

I’ve attempted to bung our conventional heating system to change some upstairs bedroom radiator valves and respective radiators. I’ve noticed when I bung the system the bathroom and kitchen taps appear to drain off if I open them, however the radiator pipes appear to constantly flow with water.

Could I please have some advice on whether I’m missing something? Thanks!

 

[HERTS P&D]

You are bunging the wrong 'tank'.

Andy

 

[CountryFan]

Do you have a feed and expansion cistern for heating?

 

[zakaryfaithfull]

So I have 2 tanks, one larger than the other.

The large one (the one I initially tried to bung) is pretty full of water and is the one that appears to work for the taps as mentioned.

The smaller tank next to it only has a small amount of water in it, and the water is very low and dirty. So I’m not entirely sure how I’d bung this one? As there’s no outlet hole below the water level as seen in the pics.

Again, any advice much appreciated! I can do the pipe work, valves etc. but can’t seem to nail this part

 

[Tricky-Dicky]

There will be an outlet on the smaller tank, otherwise the tank serves no purpose!
The higher white pipe is the overflow/warning pipe.
I think I can see an outlet pipe near the bottom of the tank, below the white overflow tank. A torch or feeling for it might confirm.
PS, you will also need to 'bung' the vent pipe, that discharges above the water level (yours has a green verdigris coating).
I couldn't get the bunging trick to ever work for me, but a plumber who recently replaced out system boiler could, and it worked a treat!
Best of luck.