T059_F: Water Sensed
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. However, if drain is completely blocked in common drain, condensation from the cooling coil in an up-flow configuration with a vent stand pipe above the sensor, water can back up into the secondary heat exchanger and eventually leak internally or get into inducer housing.
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 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.
4. A blocked drain in the main drain after the furnace and evaporator coil could cause water to back up into the furnace even in cooling mode in an up-flow arrangement. Even though this will not shut the cooling down, water will eventually leak inside 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.
4. Clear drain all the way to its termination. Make sure furnace condensate piping is correct with vent tee and the vent tee is NOT used to manage evaporator coil condensate.
It is recommended to use separate drains for furnace and evaporator coils. If a common drain is used, vent tee for furnace should be well above any consolidation of drain lines.
A059_F: Water Sensed
If water is sensed four consecutive times during the same call for heat. It will alternate on the IFC as a fault 59, and a fault 10 (One Hour Lockout)on the two 7 segment LED’s.
