Tech Tip 4

Danfoss electronic control modules in current production

     In 1996 Danfoss released their variable speed BD energy efficient compressors. Lowering compressor speed manually by changing resistance in the thermostat's electrical wiring daily energy consumption can be reduced on many refrigerated box applications. These new variable speed control modules are also equipped with a microprocessor, troubleshooting, LED similar to an automobile computer. Although the control module is LED ready, some job shops require you to purchase an expensive option in order to get dealer installed LED.

     No longer will Danfoss provide fuse protection on BD 35 and BD50 electronic control modules. Responsibility for preventing fire or power damage to the module is left to the person installing the system. Installation instructions vary with system design as to wire size and wire distance. To protect electronic module from damaging voltage spikes and module failures due to repeated cycling caused by low voltage, Positive and Negative power wiring should be independent of all other boat wiring by avoiding branch circuit busses.

Module protection relies on the correct size fuse and also battery to dampen out power surges so larger gauge refrigerator wiring is good as long as fuse protection meets Danfoss recommendation.

     Another installation requirement by Danfoss for BD50 compressors intended to be operated at high RPM is that the module needs an extra Fan to move the air over its heat sink..

Danfoss Electronic control Module model numbers are confusing because the last number identifies how many were in the shipping box. End number 0 stands for one in the box and a 1 stands for 30 in a shipping container. This means that 102N0210 and 101N211 are the same unit.

     Compressor manufacturer Danfoss offers several other module model options than their standard 101N210 model for both BD35 and BD50 compressors:

  • 101N0220 Module EMI Shielded unit protects against RF noise and other radiated emissions. Introduced in 2003 and still available.
  • 101N0300 AEO Module Automatic speed controller to produce Adaptive Energy Optimization. This unit, by finding the most energy efficient lowest rpm, balances all components of a system and a box’s hourly heat load. Introduced in 2003 but not used as standard equipment by any of the Job Shops selling icebox conversion refrigeration units kits.
  • 101N0500 Electronic Module with built-in AC to DC converter. This extends battery bank life for boats spending lots of time plugged into shore power.
  • 101N0230 BD 50 F Hard Start Module Intended to solve the compressor’s first start up with a warm box in hot climates. Introduced in 2004

Danfoss electronic control modules no longer available from Danfoss

     Older fixed speed BD 2, BD 2.5, and BD 3 Danfoss fixed speed compressors covering some twenty plus years prior to 1996 used a totally different design. Danfoss produced a number of different electronic module models before 1996 as product improvements but in the end they all performed much the same. That story with pictures available on my web site Click on MODULES.