Rheem HPWH-A108: Understanding and Resolving Condensate Blocked Alarms

What is the A108 Alarm?

The A108 alarm signifies that the condensate rope sensor has become wet. This typically occurs when condensation, generated during the heat pump's operation, cannot drain properly due to a blockage in the condensate drain line or pan. This leads to water backing up and triggering the sensor.

Common Causes Identified

• Clogged Drain Line/Pan: The most frequent cause of the A108 alert.
• Faulty Condensate Rope Sensor: Especially noted in new installations.
• Defective Control Board: A less common, but possible, electronic issue.

Troubleshooting Overview

This bulletin outlines essential troubleshooting steps to diagnose and resolve the A108 alarm. Key actions include:

• Performing initial checks by clearing the alarm and powering down the unit.
• Inspecting and cleaning the condensate drain line and drain pan for obstructions.
• Testing the condensate rope sensor by temporarily disconnecting it to see if the alarm persists.
• Diagnosing the control board if sensor tests do not resolve the issue.

Necessary tools for these procedures include a flathead and a Philips head screwdriver.