Barker PTD-RGC Installation & Operation Manual page 21

Defrost & Temperature Control Thermostat
The defrost termination control thermostat and the
temperature control thermostat are located in one of two
places depending on the rear sill. For cases with a standard
fl at rear sill the thermostat is located in the sliding ballast
tray on the bottom. For cases with an extended rear sill the
thermostats are located under the rear sill behind an easily
removable cover.
To access the thermostats on cases with a standard fl at rear
sill it requires that the rear panel be removed. For cases with
an extended rear sill, access to the thermostats simply by
lifting off the ballast cover from under the rear sill.
It is important to consult the control setting guidelines shown
on pages 2-9 before setting defrost times. Further adjustment
may be required depending on store conditions.
DETERMINING SUPERHEAT
To identify proper superheat settings, complete the following:
1. Obtain suction pressure from access port; obtain suction
line temperature from area near TXV bulb at the outlet of
evaporator coil.
2. Using the suction pressure reading, convert pressure to
temperature using temperature pressure chart (see
Appendix C1).
3. Finally, subtract the converted temperature reading from
the actual temperature reading for superheat setting.
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AIRFLOW & DEFROST