62 AGZ 010B through 034B IOMM AGZB1
Service
!
WARNING
Disconnect and tag out all power sources to the unit before doing any service inside the
unit. 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 special
regard to regulations concerning release of refrigerant to the atmosphere.
Note: Repeated tripping of equipment protection controls must be investigated and
corrected.
Thermostatic Expansion Valve
The expansion valve is responsible for allowing the proper amount of refrigerant to enter
the evaporator regardless of cooling load. It does this by 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 8°F to 12°F (4.4°C to 6.6°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 counterclockwise to reduce superheat.
Allow time for system rebalance after each superheat adjustment.
The expansion valve, like the solenoid 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.
Filter-Driers
If the pressure drop across the filter-drier is in the 6 to 10 psi range, it should be monitored
and changed when the pressure drop reaches 10 psi. 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 unit to operation.
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 by 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.
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