When my system is idle and not refilling a tank, the RODI system has started making a hissing noise frequently (every minute or so). The RODI pressure valve starts at 40psi when idle and slowly builds up to 50ish. Then there is a pressure release (I think from the auto-flush valve) and the psi drops back to 40ish - only to repeat (see video). Is this normal? Before adding the auto-flush valve it would hold steady when idle.
Auto-Flush Valve Pressure Release
Auto-Flush Valve Pressure Release