Rheem 96P series Installation Instructions Manual page 97

TABLE 20 (continued)
90P 2 STAGE FAULT CODES WITH DESCRIPTIONS AND SOLUTIONS
STATUS: This is a critical fault experienced by the furnace. The furnace will not operate in gas heat modes but all other modes
(e.g. cooling) should function if a call is present.
DESCRIPTION: The IFC cannot detect electrical continuity between pins 1 and 2 of connector P4 of the furnace control. The
IFC looks for continuity between these pins to determine if the water sensors (2) are present in the circuit. When both sensors
are present and properly connected and wiring is not damaged, there should be electrical continuity between these pins.
EXPECTED OPERATION: No gas heating operation can proceed and the fault is displayed. All other modes (e.g. cooling) of
operation should operate as normal.
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CAUSE:
(1) Wiring has been damaged between the control or sensor.
(2) Connection of P4 at the IFC or at the water sensors is not properly made.
(3) Water sensor has been removed.
SOLUTION:
(1) Repair or replace wiring.
(2) Repair connections or replace wiring or sensors or controls as necessary.
(3) Replace missing water sensor.
STATUS: This is a critical fault experienced by the furnace. The furnace will not operate in gas heat modes but all other modes
(e.g. cooling) should function if a call is present.
DESCRIPTION: The IFC has detected current flowing from pin(s) 1 and/or 2 of connector P4 of the furnace control. The IFC
looks for current flow from these pins to determine if water is present in the collector box. When water is present, the sensor will
pass a small amount of electrical current to the sheet metal of the furnace. This current flow will notify the IFC that water is
present.
Note: The condition must be present continuously for at least ten seconds before the IFC will declare the fault.
EXPECTED OPERATION: No gas heating operation can proceed and the fault is displayed. All other modes (e.g. cooling) of
59 operation should operate as normal.
CAUSE:
(1) A blocked condensate drain or the drain trap has become blocked and cannot allow condensate water to flow properly.
(2) Wiring to the sensors has been damaged and exposed wiring is touching the furnace sheet metal.
(3) Water sensor has been removed from the collector box with wires still attached and the metal probe is touching the sheet
metal portion of the furnace.
SOLUTION:
(1) Remove/Repair drain blockage.
(2) Replace/Repair wiring between IFC and both sensors.
(3) Return sensor(s) to proper location in the collector box.
WATER CIRCUIT OPEN
WATER SENSED/BLOCKED DRAIN
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