by stoneyboy »
Tue Feb 09, 2021 11:01 pm
Hi timce
If your hot water cylinder has been around for a while the most likely cause it that the heating coil has perforated.
Presumably your CH expansion tank is higher than your cold water tank so you can check for perforation by tying up the ball valve in the expansion tank, turning off CH and HW and see what happens to the water levels.
Regards S