A058_F: Water Circuit Open
Status
This is a critical fault. The furnace will not operate in gas heat modes but all other modes(e.g. cooling) should function. This occurs on 90+ furnaces only.
Description
The control cannot detect electrical continuity between pins 1 and 2 of connector P4 of the furnace control. The control 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 on a 90+ furnace.
Expected Operation
No gas heating operation will proceed and alarm "A058_F Water Circuit Open" is declared. All other modes (e.g. cooling) of operation should operate as normal.
Cause
1. Wiring has been damaged between the control or sensor. This may be a result of seepage of water though the sensor to the Molex connector. Check the harness continuity. This circuit uses a very small current for the water sense and open circuit that only as small amount of corrosion can cause the circuit to fail.
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 harness. If corrosion has occurred as moisture leakage through sensor, replace harness and sensor.
2. Repair connections or replace wiring or sensors or controls as necessary.
3. Replace missing water sensor.
