Hillphoenix OHMA-NRG, Installation & Operation Manual

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AIRFLOW, DEFROST & TEMP CONTROL
AIR FLOW & PRODUCT LOAD
Cases have been designed to provide maximum product
capacity within the refrigerated air envelope. Please keep
products within the load limit line shown on the diagram
below (Fig. 4).
It is important that you do not overload the food product dis-
play so that it impinges on the air flow pattern. Overloading
will cause malfunction and the loss of proper temperature
levels, particularly when discharge and return air sections
are covered.
DEFROST & TEMPERATURE CONTROLS
OHMA cases are equipped with timed-off defrost. When
timed-off defrost is used, the refrigeration cycle is turned off
by the case controls for a specified amount of time; there-
fore, there are generally no active defrost components uti-
lized.
The discharge air probe monitors the temperature of the
discharge air and may be used as the defrost termination
sensor. The probe can generally be found behind the rear
baffle, in the upper baffle, or in front of the honeycomb.
For more detailed information on suggested defrost times
and settings, see Appendix A . Further adjustment may be
required depending on store conditions.
Fig. 5 Obtain pressure and temperature readings
SUCTION
LINE TEMP
READING
SUCTION
PRESSURE
READING
TXV
BULB
DETERMINING SUPERHEAT
To identify proper superheat settings, complete the follow-
ing:
1. Obtain suction pressure from access port; obtain suc-
tion line temperature from area near TXV bulb at the
outlet of evaporator coil (Fig. 5).
2. Using the suction pressure reading, convert pressure
to temperature using temperature pressure chart ( see
Appendix D ).
3. Subtract the converted temperature reading from the
actual temperature reading for superheat setting.
Fig. 4 Airflow
RETURN
AIR
DISCHARGE
AIR
AIR FLOW
LOAD
LIMIT
6
• P111801H