Reznor JT4BD Unit Installation Manual - Manual (Page 11)

11
High Pressure Switch (HPS) - A high-pressure switch is
factory-installed and located in the compressor discharge
line internal to the outdoor unit. The switch is designed to
de-energize the system when very high pressures occur
during abnormal conditions. Under normal conditions, the
switch is closed. If the discharge pressure rises above
575 psig, then the switch will open and de-energize the
outdoor unit. The switch will close again once the liquid
pressure decreases to 460 psig. Please note that the
switch interrupts the thermostat inputs to the unit. When
the switch opens and then closes, there will be a 5 minute
short cycling delay before the outdoor unit will energize.
low Pressure Switch (lPS) - A low-pressure switch is
factory-installed in select models only. If provided, this
located in the suction line internal to the outdoor unit. The
switch is designed to protect the compressor from a loss
of charge. Under normal conditions, the switch is closed.
If the suction pressure falls below 5 psig, then the switch
will open and de-energize the outdoor unit. The switch
will close again once the suction pressure increases
above 20 psig. Please note that the switch interrupts the
thermostat inputs to the unit. When the switch opens and
then closes, there will be a 5 minute short cycling delay
before the outdoor unit will energize.
t4BD rEFrIgErant cHargIng cHartS - coolIng onlY
application notes on the use of charging charts
notES:
1. All pressures are listed psig and all temperatures in °F
2. Discharge temperatures GREATER than charted values
indicate an UNDERCHARGED system.
3. Discharge temperatures LESS than charted values
indicate an OVERCHARGED system.
•
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 (Figures 6 - 12, pages 14 - 17), 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)
lEgEnD
Shaded boxes indicate flooded conditions.
Rated design values. The suction pressure
will be lower than design value if outdoor air
flow, entering dry bulb, or entering wet bulb
temperatures are lower than design.
• Inspect the outdoor coil at the beginning of each cooling
season. Remove any debris. Clean the outdoor coil
and louvers as necessary using a mild detergent and
water. Rinse thoroughly with water.
• Inspect the electrical connections for tightness at the
beginning of each heating and cooling season. Service
as necessary.
cautIon:
the unit should never be operated without a
filter in the return air system. replace disposable
filters with the same type and size.
• Do not add additional oil to motors unequipped with oil
tubes. The compressor is hermetically sealed at the
factory and does not require lubrication.
coMPonEnt FunctIonS
comfort alert tM Diagnostics - The Comfort Alert
diagnostics module troubleshoots heat pump and air
conditioning system failures and accurately detects the
cause of electrical and system related failures without
any sensors. A flashing LED indicator communicates the
ALERT code to quickly direct the technician to the root
cause of a problem.