Why isn't my Bosch SM070 Heat Pump switching between heating and cooling?
- MMartha SavageSep 6, 2025
If your Bosch Heat Pump isn't shifting between cooling and heating modes, a faulty solenoid could be the cause. Check that the reversing valve solenoid is receiving 24 VAC; if it is, check the resistance of the solenoid, as an open circuit may indicate a burned-out solenoid. A miswired or faulty thermostat could also be the problem; ensure that the reversing valve thermostat wire is connected to the "O" terminal of the thermostat. Finally, check for a loose wire on the "O" terminal, ensuring that the wires from the thermostat to the unit are securely connected, as well as the wires from the electrical box to the reversing valve.






