TROUBLESHOOTING REFRIGERATION COMPRESSORS
(Older Adler-Barbour, Grunert, Sea Frost, Technautics, etc.):
Newer Danfoss compressors BD3.5 and BD5.0 have a built in troubleshooting computer chip to make it much easier to find and solve problems.
Older Danfoss Compressors # BD 2, BD 2.5, and BD 3
Ninety percent of the time it is not the compressor
, or refrigerant system that causes the failure of the compressor
to start. The Danfoss electrical
modules are prone to failure.
If you have bypassed the thermostat at the module, and run the following tests, I would have the module tested. They no longer manufacture modules for the BD2.5 or BD3 compressor but they are available from Frigoboat http://www.frigoboat.com/home.html
PN E254412 - Price
: $198.00 http://www.frigoboat.com/Merchant2/m...de=otheraccess
Note: See the Frigoboat web-site (above) for some excellent refrigeration tutorials.
Repeated failure of start, and an audible cycle beep is caused by a program in the electronic module unit. It is programmed to stop the compressor if;
1. Low Voltage (<11.5VDC)
If the voltage is below 11.5 volts during start. Check batteries for charge. Check for a high-resistance connection. The best and quickest way to do this is run a temporary set of wires from a fully charged battery
to the compressor electrical
module. The wire size and polarity is important.
2. HIGH FAN/PUMP CURRENT
(> 1 Amp)
If the fan or if water-cooled, the pump relay, is drawing more than one amp. To check, disconnect one of the wires to fan. If the compressor starts OK replace fan or pump or relay.
3. HIGH COMPRESSOR CURRENT
(> 7.5 Amps)
If the compressor is going bad and drawing more than 7 1/2 amps. To check, install an ammeter in the power wire to the refrigeration unit. It should draw 5 to 6 amps when running - if more than 7 amps, the compressor is about to fail. To do this test, the unit must be running. It is sometimes possible with a failed compressor to see a quick movement of the ammeter to 10 amps. or higher.
4. COMPRESSOR RESISTANCE:
The best test to determine condition of the compressor field windings is to check their resistance with an ohmmeter*.
Resistance between terminals 1 and 2 is 0.2 ohms.
Resistance between terminals 4 and 3 is 0.2 ohms.
Resistance between terminals 2 and 3 is 3.5 ohms.
5. If the compressor tests bad, do not install a new module on it.
6. If the compressor checks out, have the Module tested
* Pin Locations:
Pin 1 is located at the 2:30 clock position, Pin 2 at 11:00, Pin 3 at 5:30, pin 4 at 8:30.
Take care in removing the connector plug
from the compressor.