What causes water hammer in my Bosch LV015 Heat Pump and how to fix it?
- ZzclarkSep 23, 2025
If you're experiencing water hammer with your Bosch Heat Pump, the cause may be fast closing valves. In this case, change the valves to a slow-close type.

What causes water hammer in my Bosch LV015 Heat Pump and how to fix it?
If you're experiencing water hammer with your Bosch Heat Pump, the cause may be fast closing valves. In this case, change the valves to a slow-close type.
How to reduce objectionable noise levels from my Bosch LV015 Heat Pump?
If you're experiencing objectionable noise levels from your Bosch Heat Pump, ensure the duct work and grilles are properly sized for unit air flow. If the fan speed setting is too high, consult the blower performance table and reduce fan speed if possible. To address structure borne noise, mount the unit on a vibration pad. Also, install the unit in accordance with the provided instructions and adjust the unit location to prevent it from touching the structure.
What to do if my Bosch LV015 compressor isn't running and the fan is on, but I suspect low refrigerant?
If your Bosch Heat Pump's compressor isn't running but the fan is, it could be due to a low-pressure fault caused by low refrigerant. Check the refrigerant pressure with a gauge set.
What to do if the compressor of my Bosch Heat Pump doesn't work but the fan runs and there is a freeze fault?
If your Bosch Heat Pump's compressor isn't running but the fan is, it could be due to a freeze fault in the water coil caused by no or low water flow. Check the water valves and/or pumps to ensure they are operating correctly. Also, check the water coil for any blockages.
Why is my Bosch Heat Pump compressor not running but the fan is, possibly due to high water temperature?
If your Bosch Heat Pump's compressor isn't running but the fan is, it could be due to a high-pressure fault caused by high water temperature. Check the water temperature to ensure it is within the appropriate range.
What to do if the fan is not working on my Bosch LV015 Heat Pump with a PSC motor?
If the fan on your Bosch Heat Pump isn't working (PSC motor), first check the supply voltage from the fan relay to the motor and ensure that all motor wires are secure. With the power off, spin the motor shaft; noise, resistance, or uneven motion can indicate motor failure. Also, check for 24 VAC across the fan relay coil and check all wiring connections. If the relay coil is energized but the relay does not pull in, check the resistance across the relay coil; an open circuit indicates a faulty relay.
What to do if the compressor is not working but the fan runs on my Bosch LV015 Heat Pump, and it might be related to a brown out fault?
If the compressor of your Bosch Heat Pump isn't working, but the fan is still running, it could be due to a brown out fault. This could be caused by low supply voltage, so check the primary voltage to ensure it is within the limits listed on the unit data plate. Another cause may be an overloaded control circuit; if the control voltage is below 18 V, check accessories connected to the unit and ensure that they do not exceed the VA draw. A bad thermostat connection can also cause this issue, so check that the thermostat wiring is the proper gauge and length, that it is not damaged, and that all connections at the thermostat and heat pump are secure.
What to do if the compressor is not working but the fan runs on my Bosch LV015 Heat Pump, and it might be related to thermostat?
If the compressor of your Bosch Heat Pump isn't working, but the fan is still running, ensure that the thermostat is on and calling for 'Y'. Check the 'Y' connection from the thermostat, ensuring that there is 24 VAC between 'Y' and 'C'. Also, check the wiring to ensure that there is 24 VAC across the contactor coil. Finally, test the contactor with 24VAC (between 'R' and 'C'). Ohm the contactor coil; an open circuit indicates a burned coil.
Why is my Bosch LV015 compressor not running, but the fan is, possibly due to condensate drainage issues?
If your Bosch Heat Pump's compressor isn't running but the fan is, it could be due to a condensate fault caused by poor drainage. Check the condensate pan for a high water level. Check the drain line for blockages, double trapping, or inadequate trapping.
How to troubleshoot a Bosch LV015 Heat Pump with no compressor operation but running fan, possibly due to a bad thermostat connection?
If the compressor of your Bosch Heat Pump is not working, but the fan is running, it might be due to a brown-out fault caused by a bad thermostat connection. Check that the thermostat wiring is of the proper gauge and length, is undamaged, and that all connections at the thermostat and heat pump are secure.
| Refrigerant | R410A |
|---|---|
| Cooling Capacity | 5.0 kW |
| Sound Level | 45 dB |
| Heating Capacity | 16, 000 BTU/h |
| Noise Level (Outdoor Unit) | 45 dB |
| Weight (Indoor Unit) | 12 kg |
| Weight (Outdoor Unit) | 35 kg |
| Dimensions (Indoor Unit) | 700 x 250 x 190 mm |
| Dimensions (Outdoor Unit) | 780 x 290 x 540 mm |
Provides critical safety information before installation and servicing.
Details on how to mount vertical and horizontal units, including vibration pads and pitching.
Procedures for installing the condensate drain line, including slope and trap requirements.
Instructions for wiring the high voltage power supply to the unit according to codes.
Lists safety features and UPM board functions like anti-short cycle and freeze protection.
Checklist of essential system checks before initial unit startup.
Steps for starting the unit in cooling/heating modes and verifying performance.
Diagnosing and resolving issues when the compressor doesn't run but the fan does.
Diagnosing freeze faults related to water flow or low refrigerant.
Diagnosing issues with condensate, low voltage, brown outs, and air coil freeze faults.
Addressing thermostat connection problems and reversing valve operation.
Diagnosing compressor faults, power supply problems, and control transformer issues.
Diagnosing issues with PSC fan motors, including faulty motors or relays.
Diagnosing ECM motor faults and problems with the unit not shifting into cooling.