Hi
When secondary return pump is on theres no flow to hotwater taps but when the pump is not running water flows through tap.
Any one come across this before??
There’s your problem bet it’s less than 5m to the tanks (high) the check valves are too high of a resistance and there not opening eg tmv on gravity crap
Water taking the path of least resistance when the pumps on
With the pump pressure the water wants to flow round the loop rather than out the taps either slow the pump down or make more resistance on the return tapping at the tank
With the pump pressure the water wants to flow round the loop rather than out the taps either slow the pump down or make more resistance on the return tapping at the tank