Carrier EverFRESH Operation, Service And Parts Manual page 28

AL977 Membrane Pressure Transducer (MPT) Fault
Cause: When the EverFRESH Air Compressor (EAC) is running and pressure is not between -5 psig and 200
psig or the EAC has been OFF for five minutes and pressure is not within the range of -5 psig and 5
psig.
Component Membrane Pressure Transducer (MPT)
Troubleshooting With the EverFRESH system off for 15 minutes, bring up function code Cd44
Component ML5 Controller
Troubleshooting Access function code Cd74 to perform an ML5 self-diagnostic test.
AL978 Air Compressor Pressure Low
Cause: EverFRESH Air Compressor (EAC) engaged and Fresh Air Vent (FAV) and Water Drain Valve
(WDV) are closed and compressor has been running for longer than 20 seconds and Membrane
Pressure Transducer (MPT) pressure is less than 75 psig.
Component Membrane Pressure Transducer (MPT)
Troubleshooting With the EverFRESH system off for 15 minutes, bring up function code Cd44
Component System Plumbing
Troubleshooting Inspect plumbing, hoses, fittings, check valve, and orifices for signs of
AL979 Air Compressor Pressure High
Cause: EverFRESH Air Compressor (EAC) engaged and pressure is more than 135 psig.
Component Membrane Pressure Transducer (MPT)
Troubleshooting With the EverFRESH system off for 15 minutes, bring up function code Cd44
Component System Plumbing
Troubleshooting Inspect plumbing, hoses, fittings, check valve, and orifices for signs of
T-374
Table 4–1 Alarm Indications and Descriptions
and scroll to "EF Pt". Verify that the value is between -5 psig and 5 psig. A "-
- - - " value indicates a failed sensor or harness. Pressure outside of range
indicates a bad sensor, replace the sensor.
and scroll to "EF Pt". Verify that the value is between -5 psig and 5 psig. A "-
- - - " value indicates a failed sensor or harness. Pressure outside of range
indicates a bad sensor, replace the sensor.
leakage. Repair as required.
With the compressor running, spray the pressure relief valve with soapy
water. Replace if leaking. If a spare pressure relief valve is not available, try
opening and closing the valve with an O-Ring on the valve to try and re-seat.
See the condition for Membrane Pressure Transducer (MPT) Reading Low in
Section 4.2
EverFRESH Troubleshooting.
and scroll to "EF Pt". Verify that the value is between -5 psig and 5 psig. A "-
- - - " value indicates a failed sensor or harness. Pressure outside of range
indicates a bad sensor, replace the sensor.
blockage. Repair as required.
See the condition for Membrane Pressure Transducer (MPT) Reading High in
Section 4.2 EverFRESH Troubleshooting.
4–4