P4AX : High Pressure A

Pressure in the hose and pumps will increase as the system heats up.  Turn on heat and allow all zones to reach the temperature setpoint before turning on the pumps.


Verify the ADM pressure reading and the analog guages at the manifold.  Replace transducer if they do not match.


Alarm level is lower for H-30, H-40 and H-50 than for H-XP2 and H-XP3.  Ensure dial on HCM is set to position "3" for H‑XP2 or "4" for H‑XP3.