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Quantum Energy Technologies
Owners Manual
6h: Service Warnings
WARNING
Disconnect and tag out all power sources to the unit before doing any service inside.
Failure to do so can cause severe personal injury or death.
CAUTION
Service on this equipment is to be performed by qualified service personnel with
particular regard to regulations concerning release of refrigerant to atmosphere.
Note: Repeated tripping of equipment protection controls must be investigated and corrected.
6i: Thermostatic Expansion Valve
The expansion valve is responsible for allowing the proper amount of refrigerant to enter the
evaporator and maintaining a constant superheat. (Superheat is the difference between refrigerant
temperature as it leaves the evaporator and the saturation temperature corresponding to the
evaporator pressure.) Typically, superheat should run in the range of 4°C to 7°C).
The superheat setting can be adjusted by removing the cap at the bottom of the valve to expose the
adjustment screw. Turn the screw clockwise (when viewed from the adjustment screw end) to
increase the superheat setting and counter clockwise to reduce superheat. Allow time (at least
15min) for the system to rebalance after each superheat adjustment.
The expansion valve should not normally require replacement, but if it does, the unit must be
pumped down by following the steps involved when changing a filter drier.
If the problem can be traced to the power element only, unscrew the element from the valve body
without removing the valve, but only after pumping the unit down.
6j: Filter Drier
If the pressure drop across the filter drier is in the 40 to 70kPa range, it should be monitored and
changed when the pressure drop reaches 70kPa. To change the liquid line sealed filter, de-energize
the unit and pump out the refrigerant. After changing the filter drier, check for leaks before
recharging and returning the unit to operation.
6k: Liquid Line Solenoid
The liquid line solenoid valve does not normally require any maintenance. It may, however,
require replacement of the solenoid coil. The solenoid coil may be removed from the valve body
without opening the system, after disconnecting power to the unit. The coil can then be removed
from the valve body by simply removing the nut or snap ring located at the top of the coil.
Page 27 of 33
Document Number : QDC0049PD-5
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Troubleshooting
