Danfoss BD35F variable speed refrigeration compressors are designed for connection to 12V and 24V DC power supply and for refrigerant R134a. These compressors can be used in refrigerators and freezers using either capillary tube or TEV as the throttling device. Danfoss BD compressors especially used in mobile applications such as boats, cooling boxes, caravans, buses, vans, trucks, etc. If you are looking for Danfoss BD35F compressor troubleshooting, read on to this entire blog to repair it easily.

Danfoss BD35F Compressor Troubleshooting

These compressors are also suitable for stationary applications powered by photovoltaic solar panels due to their low energy consumption and wide supply voltage range. Before starting the Danfoss compressor troubleshooting process, we will have a look at a few instructions on the compressor.

The Danfoss BD compressor includes an electronic unit. It has features battery protection, overload protection, fan, LED, and lamp connections, load dump and adaptive energy optimizing. This electronic unit has internal voltage recording and calibration to the applied voltage. It is also powered directly from certain types of electronic power supply units so that no particular battery is required.

Danfoss BD compressors should be mounted in a dry and clean place. They will withstand storage temperatures down to -35°C.

Condensing temperatures:

At stable conditions, maximum 60 degrees C and 70°C at peak load.

Ambient temperatures: Max. 55°C and Min. -10°C.

You should use filter driers which are declared by the Danfoss only in the refrigeration systems with BD compressors. Filter material powder ending up in the compressor will lead to excessive wear of the piston. And, transmission parts deposited in the motor windings will cause the compressor to stop because the electric signal back to the electronic unit is disturbed.

The electronic unit should be mounted on the compressor. It always be connected to the battery poles or power supply unit terminals directly. You should install an external fuse in the power supply cable close to the battery or power supply unit.

If the compressor is to be stopped for a long period, you can install the main switch to avoid the battery from being drained.

Danfoss BD Compressor Troubleshooting

Is your Danfoss compressor stops working? It is recommended to use a LED which is installed between the terminals + and D to determine why your compressor not working.

You should check the electronic unit that is connected properly to the power supply.

Verify if the thermostat is ON.

The number of flashes emitted by the LED will give you a hint about the cause for interruption of compressor operation.

Check the motor windings for defects by measuring the resistance between the current lead-in pins.

If the measured resistance values between all three pins are approximately same, consider that the motor is most likely all right.

Here, you can check the error types based on the number of flashes emitted by the LED.

1 flash - Battery protection cut-out.

The voltage is outside the cut-out setting.

2 flashes - Fan over-current cut out.

The fan loads the electronic unit with more than one Amp.

3 flashes -Motor start error.

The rotor might be blocked or the differential pressure in the refrigeration system is too high.

4 flashes -Minimum motor speed error.

If the refrigeration system is overloaded, then the motor cannot be maintained a minimum speed at approximately 1850 rpm.

5 flashes -Thermal cut out of the electronic unit.

If the refrigeration system has been too heavily loaded or the ambient temperature is high, the electronic unit will run too hot.

Protection Systems

Danfoss BD35F compressor system has facilities against its overload and starts failure, fan overload, electronic unit loading, and destructive battery discharge. When the overload protection feature is activated, the compressor enters a cycle in which it attempts to start at 66 seconds intervals approximately until a successful start is achieved.

Voltage protection - If a voltage other than the specified range is applied to the electronic unit, then the compressor doesn't start or it stops the exceeded voltage limit during operation. Moreover, your BD compressor will restart after a minute automatically when the supply voltage has reached the reset voltage. If a fan is there, it also starts running automatically without a delay once the reset voltage is reached.

Battery protection - The Danfoss BD electronic unit has integrated battery protection to avoid permanent damage to the battery due to heavy discharge and to ensure sufficient battery power for the correct operation of the compressor. Moreover, the compressor is stopped and restarted again as per dedicated voltage limits measured on positive and negative terminals of the electronic unit.

Final Words

Danfoss BD compressors bring comfort at work and leisure. So, when you get problems with the Danfoss compressor , repair it quickly. However, we hope this Danfoss BD35F compressor troubleshooting guide helped you to fix the problem. Additionally, you can get more information regarding Danfoss BD compressor troubleshooting, safety precautions, etc. in the owner's manual. Stay connected with us to get more HVAC components troubleshooting tips.