E14
Rheem
Reversing Valve (O/B) Control Fault
Thermostat shows E14 and may indicate 'Reversing valve control error' on heat pump systems.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Open or shorted O/B control wire, Misconfigured O/B setting (energize in heat vs cool), Failed reversing valve coil, Defective O/B output driver in thermostat
How to Fix / Troubleshooting
Safety first: Turn off power to indoor and outdoor units before touching wiring or the outdoor valve coil.
Steps:
- Verify configuration: In the Rheem thermostat installer menu, confirm the O/B setting matches the Rheem heat pump requirement (typically O = energized in cooling for many systems; check documentation).
- Check O/B wiring: Ensure the O/B terminal on the thermostat is connected to the O/B terminal on the indoor and outdoor units as per Rheem's wiring diagram.
- Test coil resistance: At the outdoor unit, disconnect the reversing valve coil and measure its resistance. A very high (open) or very low (shorted) reading indicates a bad coil.
- Check 24V at O/B: With a call for cooling (or heating, depending on configuration), measure 24VAC between O/B and C at the outdoor unit. If no voltage and E14 is present, suspect thermostat or wiring.
- If coil is good and voltage present but valve does not shift: The reversing valve itself may be mechanically stuck and requires professional service.
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Repair Difficulty
Hard
4/5
Required Part
Reversing Valve Coil
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