How to stop water hammer in my Bosch SM036 system?
If you're experiencing water hammer with your Bosch Heat Pump, it's likely due to fast-closing valves being installed. Change the valves to a slow-close type to resolve this issue.
Why does Bosch SM036 Heat Pump UPM board show fault in test mode?
If your Bosch Heat Pump operates in test mode but the UPM board shows a fault, it's likely because the UPM board is in test mode. Change the dip switch setting to Normal. This is part of the test mode to ensure that freeze 1 and freeze 2 sensors are correctly located.
Why does my Bosch SM036 have no delay on startup?
If your Bosch Heat Pump operates but has no or short delays on start or restart, the UPM board might be in test mode. To resolve this, change the dip switch setting to Normal.
Why isn't my Bosch SM036 Heat Pump switching between heating and cooling?
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.
What to do if the fan on my Bosch SM036 Heat Pump isn't working?
If your Bosch Heat Pump's ECM constant airflow motor isn't operating, there could be several reasons. First, check for 24 VAC between "G" and "C" and verify all wiring connections, as there may be no fan operation signal. Loose wiring can also cause this issue, so check all wiring connections at the motor and control box, ensuring that power and control harnesses are securely connected. Interface board problems could also be the cause; make sure the interface board isn't damaged and that all DIP switches are in the proper configuration. Finally, a faulty motor could be the problem; check the supply voltage to the motor and ensure all motor wires are secure.
How to fix excessively cold air from Bosch SM036 in cooling?
If your Bosch Heat Pump is producing excessively cold air during cooling or excessively hot air during heating, it could be due to reduced airflow. Try replacing the filter. The fan speed might be too low, so consult the blower performance table and increase fan speed if possible. Also, excessive duct pressure drop can cause this issue; consult the blower performance table and increase fan speed if possible.
Why is my Bosch Heat Pump blowing warm air in cooling mode?
If your Bosch Heat Pump is providing excessively warm air in cooling or excessively cool air in heating, several factors could be responsible. The airflow might be too high; consult the blower performance table and reduce fan speed if possible. High or low water temperature could also be a cause; check the unit's capacity versus the water temperature. Air leakage in the ductwork can also lead to this issue, so inspect the ductwork. Finally, a loss of refrigeration capacity could be the reason; in that case, check refrigerant pressures with a gauge set.
Why is there high humidity with my Bosch SM036 Heat Pump?
High humidity with your Bosch Heat Pump can stem from several causes. The airflow might be too high, so you may consult the blower performance table and reduce fan speed if possible. Another reason could be a loss of refrigeration capacity, in which case you should check refrigerant pressures with a gauge set. Short cycling could also contribute, so check the unit's performance against building load calculations. Finally, ensure that the thermostat isn't located near a supply air duct, as a poor thermostat location can affect humidity levels.
Why is my Bosch SM036 Heat Pump fan running but the compressor isn't?
If your Bosch Heat Pump's fan runs but the compressor doesn't, it could be due to a high-pressure fault caused by no or low water flow. Check the water valves and/or pumps for proper operation and inspect for any water coil blockages. It might also be due to high water temperature; ensure it is within the correct range. A fouled or scaled water coil could also be the culprit; check for proper flow rate and water temperature. Also, check the fan motor for proper operation. Alternatively, a low-pressure fault due to low refrigerant could be the cause; in this case, check the refrigerant pressure with a gauge set. If it is a freeze fault, it may be caused by low water temperature. Check if the water temperature is below 40° entering.
Why is my Bosch Heat Pump not heating or cooling sufficiently?
If your Bosch Heat Pump isn't providing enough cooling or heating, start by recalculating the heating and cooling loads of your space; adding insulation and shading might help. Check for leaks in ductwork or ambient air entering through doors and windows. Ensure adequate airflow and proper air distribution, replacing dirty filters if needed. A low refrigerant charge could also be the cause. Check the compressor for defects. Also, compare unit operation pressures to the pressure/temperature chart for the unit. Check TXV for possible restriction or defect. The refrigerant system may be contaminated with moisture or noncondensables. Reclaim refrigerant, replace filter dryer, evacuate the refrigerant system, and recharge with factory recommended charge.
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