HVAC / Compressor Controllers
Electronic Unit for Danfoss BD35/BD50F Compressors 101N0500
Quick guide for the Danfoss 101N0500 electronic unit for BD35/BD50F compressors. Includes wiring diagrams, power supply requirements, battery protection settings, and troubleshooting error codes.
Table of contents
Quick guide from the manual
The Danfoss 101N0500 is a multi-voltage electronic unit designed for BD35 and BD50F compressors. It supports both 12V/24V DC and 100-240V AC (50/60Hz) power systems. The unit features built-in thermal protection and automatic power source switching, prioritizing AC when both are connected. Ensure all wiring meets the specified dimensions to prevent voltage drops.
Installation
Mount the electronic unit directly onto the compressor by snapping the cover over the screw head. Ensure the ambient temperature does not exceed 55°C (131°F).
Power Supply
DC Power: Connect directly to the battery poles (+ to +, - to -). A fuse must be installed in the positive cable as close to the battery as possible (15A for 12V, 7.5A for 24V). If using a main switch, it must be rated for at least 20A.
AC Power: Connect to terminals L and N. A 4A fuse must be installed in the live (L) cable. The unit operates between 100-240V AC. If AC power drops below 85V, the unit will switch to DC power after a 1-minute delay.
Battery Protection
The compressor stops and restarts based on voltage limits measured at the + and - terminals. Standard settings are pre-configured, but optional settings can be applied by connecting a resistor between terminals C and P.
Thermostat and Speed Control
The thermostat connects between terminals C and T. Without a resistor, the compressor runs at a fixed speed of 2,000 rpm. To adjust the speed between 2,000 and 3,500 rpm, install a resistor between terminals C and T. Refer to the compressor speed chart for specific resistor values.
Optional Connections
- Fan: Connect a 12V fan between terminals + and F. The output is regulated to 12V, so a 12V fan must be used regardless of the system voltage (12V or 24V).
- Lamp: A 12V 5W lamp can be connected between terminals A and C.
- LED: A 10mA LED can be connected between terminals + and D to indicate operational errors via flash codes.
Troubleshooting
If an error occurs, the LED will flash a specific number of times every 4 seconds. Common errors include thermal cut-out (system overloaded or high ambient temp), minimum motor speed error (system overloaded), motor start error (rotor blocked or high differential pressure), fan over-current (fan draws >1A), and battery protection cut-out (voltage outside limits).
Manufacturer information
Danfoss A/S
Practical help
Common problems
Thermal cut-out
The refrigeration system is too heavily loaded or the ambient temperature is too high. Ensure proper ventilation.
Minimum motor speed error
The refrigeration system is too heavily loaded; the motor cannot maintain the minimum 1,850 rpm.
Motor start error
The rotor is blocked or the differential pressure in the refrigeration system is too high (>5 bar).
Fan over-current cut-out
The fan is drawing more than 1A peak current. Check fan specifications and wiring.
Battery protection cut-out
The supply voltage is outside the configured cut-out settings.
Before use
- Verify the fuse rating: 15A for 12V DC, 7.5A for 24V DC, or 4A for AC.
- Ensure DC connections are made directly to battery poles (+ to +, - to -).
- Check that wire dimensions match the distance between the battery and the unit (see Fig 2).
- Ensure the ambient temperature is below 55°C.
- If using a fan or lamp, ensure they are 12V rated, as the output is regulated to 12V.
Model compatibility
- Compatible with BD35 and BD50F compressors.
- AC power is prioritized if both AC and DC are connected.
- A 12V fan and 12V lamp must be used even in 24V systems.
Manual page author
David Miller
Documentation analyst
Organizes user manual content into clear summaries, with attention to model details, product context, and everyday usability.