I do not know if you can help me diagnose this problem.
We have a standard system. However the cold FEED tank is HOT. With the pump running a small amount of hot water is being pumped up into the base of the Feed Tank (in addition to any expansion from the expansion pipe).
Any thoughts? Our plumber has suggested changing the Hot water storage tank suspecting an "internal" leak between the water and the heating coil. But I am suspicious of this diagnosis- as surely the hot water would be discolored from the dirty circulating water from the boiler?
Any thoughts before I commit to more expense?