Rheem Technical Service Bulletin

A108: Blocked Condensate Line

Subject: Heating Source Defaults to Elements Due to Condensate Drain Blockage

This bulletin addresses a common issue where the heating source defaults to elements because of a blocked condensate drain line in Rheem A108 units.

Troubleshooting Steps:

1. Customer Inquiry: Ask the customer where the condensate is being routed. It should be routed to an appropriate location per local or national codes.
2. Visual Inspection: Visually inspect the condensate line to ensure it is clear. If necessary, unclog the condensate line.
3. Sensor and Pan Check: Remove the top cover from the tank or pull the filter to view the condensate sensor and pan.
   • Ensure there is not excessive condensate in the condensate pan and on the sensor.
   • If water is present, dry the sensor and drain pan using a paper or cloth towel. The sensor can be unplugged for 24 to 48 hours to allow it to dry.
4. Sensor Testing: If the pan and sensor are dry and no blockage is present, check the condensate sensor with an ohm meter. The condensate sensor should read "open" (no continuity). If resistance is present, replace the condensate sensor.
   • Note: Measure resistance across the leak sensor. If it shows any continuity while dry, replace the leak sensor. Use the highest resistance scale on your meter.
   • Note: Check the sensor to ensure correct location in the drain pan. The sensor should be located in a pocket underneath the evaporator coil above the drain pan. Ensure this area is dry.
5. PCB Check: If the sensor and sensor location are dry, and the sensor checks good, unplug the sensor from the PCB (two grey wires). Allow the unit to operate for 24 to 48 hours. If the code returns, replace the PCB. Clear the alarms. The unit will operate with the sensor unplugged.

[Placeholder: Figure 1 - Visual inspection of condensate line]

[Placeholder: Figure 2 - Condensate sensor and pan view]

[Placeholder: Figure 3 - Sensor location detail]

How to Replace Condensate Sensor

This section provides step-by-step instructions for replacing the condensate sensor.

1. Power Disconnection: Turn the unit off and disconnect power at the junction box.
2. Top Pan Removal: Remove the screws around the top pan and detach the top pan.
3. Control Board Removal: Remove the control board from the front of the unit.
   • Use a flat blade screwdriver to pop off the cover surrounding the control board display.
   • Remove the 2 screws and pull off the control board.
4. Sensor Connector: Disconnect the 2-pin connector associated with the condensate sensor (two grey wires) from the control board.
5. Sensor Extraction: Reach down through the top of the heater and lift the condensate sensor from the tray.
6. Sensor Routing: Route the condensate sensor through the grommet on the edge of the evaporator.
7. New Sensor Installation: Install the new condensate sensor in the reverse order of removal.
8. Reassembly: Reassemble all components.
9. Testing: Test the operation of the heater.

[Placeholder: Figure 4 - Condensate sensor replacement procedure]

Manufacturer Information:

Rheem Water Heating

800 Interstate Park Dr. Montgomery, AL 36109

Website: www.rheem.com

In keeping with its policy of continuous progress and product improvement, Rheem reserves the right to make changes without notice.

Document Date: 6/4/2019