Reznor JS4BD (3ph) Unit Installation Manual - Manual (Page 8)

8
Charging the Unit in AC mode at outdoor temperatures
above 55° F for optimized sub-cooling of 10° F - 12° F.
1. With the system operating at steady-state, measure the
liquid refrigerant pressure (in psig) at the outdoor unit
service valve.
2. Measure the liquid refrigerant temperature (in
Fahrenheit) at the service valve.
3. Determine the required liquid refrigerant pressure from
the appropriate charging chart Tables 3, 4, & Figure 2.
• If the pressure measured in Step 1 is greater than
the required liquid refrigerant pressure determined in
Step 3, then there is too much charge in the system.
Remove refrigerant and repeat Steps 1 through 3
until the system is correctly charged.
• If the pressure measured in Step 1 is less than the
required liquid refrigerant pressure determined in
Step 3, there is too little charge in the system. Add
refrigerant and repeat Steps 1 through 3 until the
system is correctly charged.
application notes for using charging charts
•
this equipment’s cooling system contains
refrigerant under high pressure. always use safe
and environmentally sound methods when handling
refrigerant handling or servicing the unit. review
the factory literature and safety warnings prior to
servicing.
• When repairing system leaks, always use a nitrogen
(inert) gas to protect the refrigerant system and pressure
check the repair before re-charging. Always replace
the filter-dryers when performing any repair to the
refrigeration system with one capable of acid removal.
After completing the repairs, evacuate the system to
350 - 500 microns and weigh in the refrigerant to the
amount specified on the unit rating label.
• Charging charts are valid for a variety of indoor, return
air conditions and are most influenced by the outdoor
ambient temperature, outdoor fan operation and the
unit operating voltage. Before using these charts, make
sure the unit is in a stable operating mode. As shown
in the charging charts (Tables 3 & 4 and Figure 2), the
ideal system sub-cooling can vary over the range of
operation. Reference the charts to determine the ideal
amount of sub-cooling for a given liquid pressure. Units
charged to other values will not perform at the rated unit
efficiency (EER) or rated Coefficient of Performance
(COP) in heating mode.
• To inspect a systems operation using quality
instruments, match the measured liquid temperature
to the units chart. The measured liquid pressure
reading should be within 3% of the charts value for
most installations.
• For systems that are operating with more than a 5%
deviation, inspect the unit for the proper voltage and
phase balance and the refrigeration system for leaks.
• Units that are operating at less then 95% of the nominal
voltage or with a 2% phase imbalance may see a more
significant deviation than the amount stated above.
• do not use the charts in systems that have a fan cycling
under low-ambient control. Refer to the low-ambient
kit instructions for more information. (If applicable)