Service Frequently Asked Questions

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Cooling Units

Is my unit cooling unit phase sensitive?

Pfannenberg manufactures three Side Mount Cooling Units that contain compressors that are phase sensitive.  These three models are the DTS 32×5, DTS 34×1, and the DTS 31×5.

How do I tell if the phasing to my cooling unit is correct?

All cooling units that are phase sensitive will contain a phase monitor, located in the electrical box on the cooling unit.  It will be labeled “PM 1.”  On the phase monitor, there are two LED lights, one labeled “FAULT,” the other labeled “ON.”  If the LED is the color GREEN, and is labeled “ON,” the phasing is correct.

How do I tell if my cooling unit is out of phase?

All cooling units that are phase sensitive will contain a phase monitor, located in the electrical box on the cooling unit.  It will be labeled “PM1.”  On the phase monitor, there are two LED lights, one labeled “FAULT,” the other labeled “ON.”  If the LED is the color RED, and labeled “FAULT,” your cooling unit is out of phase.  Also, please note that if the unit is out of phase, the evaporator fan, and condenser fan will run, but the compressor will not.

Where is the phase monitor on my cooling unit located?

The phase monitor in the side mount cooling units can be located in two places, reason being there is two styles to the cooling unit electrical boxes.  The first style will have a site glass, on the side of the unit that bolts up to the cabinet being cooled.  Through this sight glass, you are able to view the status LED on the Phase monitor.  The second style electrical box will not contain a sight glass; however with the removal of two screws, the phase monitor is easily accessible.

Simply remove the two screws that hold the electrical box upright, and fold the electrical box down towards you.  You will then see the phase monitor located in the top right corner of the electrical box.  The LED is clearly viewable.

If my cooling unit is out of phase, what steps do I take to phase it correctly?

Properly phasing a cooling unit is a very simple process however, proper safety precautions should be taken to reduce the risk of electrical shock.  First, shut off the power that supplies the cooling unit from the enclosure (most often times via disconnect or breaker).  Next, verify that there is no voltage at the X50 power supply terminal located in the e-box of the cooling unit.  After it is proved that there is no voltage at the X50 simply use a WAGO screw driver to swap two of the three power wires going to the unit. Ensure that the wires are seated properly in the X50 terminal, and will not be able to vibrate out.  Next, restore power to the cooling unit and verify that the status LED on the phase monitor is on, and is green.

Why are the dip-switches on the control board set to 95°F/35°C?

Pfannenberg sets the dip-switches on the control board to 95°F/35°C in the factory, and recommends that the dip switch settings are not altered.  Setting the dip-switch temperature to a lower set point can cause damage not only to the cooling unit, but to the composure as well.  Changing the set point can cause the cooling unit to run excessively, possibly causing damage to the compressor and other components.  It can also cause composures to produce condensate, possibly damaging electrical components inside the cabinet.

I have connected power to my cooling unit. Why does it not run?

All Pfannenberg cooling units have an integrated door switch which is designated as X54. This door switch must be in the closed position for the cooling unit to run. If a door switch is not utilized on your cabinet, Pfannenberg has included a wire in the accessory pack that can be placed on the supplied connector jumping pins 3+4 together.