20
T5BP HEAT MODE VERIFICATION CHARTS - HEATING ONLY
•
Read all notes and warnings for the Cooling-mode charging charts prior to using these Heating-mode
charge verifi cation charts. 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 leakages, always use a nitrogen (inert) gas to protect the refrigerant system and pressure
check the repair before re-charging. Always replace the fi lter-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 specifi ed on the unit rating label.
• All T5BP-090/120 units are shipped from the factory with accumulators installed in the refrigeration system and
a 90 oz. factory holding charge.
• Before using the heat mode verifi cation charts (Figures 10 or 11, page 21), determine the outdoor ambient
temperature and the return air temperature to the unit. Locate the appropriate location on the units verifi cation
chart based on those measurements to determine the ideal liquid line pressure and temperature. Verify the outdoor
fan and compressor are running and the outdoor coil is free from frost accumulation. Also verify the system is
not operating in defrost mode before inspecting the system.
NOTE:
If the unit is equipped with an economizer,
determine the mixed air temperature entering the fi lters.
• Always use quality instruments that are in good working order to measure the actual operating point of the
refrigeration system. The liquid line temperature should be within 2 degrees of the ideal value and the pressure
should be within 2%.
• The most reliable way of verifying the system is at the correct charge is to evacuate the system and weigh in the
charge to the amount shown on the rating label. However, if an inspection with these verifi cation charts does not
line up with the values shown and the ambient temperature is above 50˚ F, then a more accurate way to inspect
the system for proper charge is with the cooling mode charging charts. Switch the unit into cooling mode and
allow it to operate and stabilize for a few minutes then inspect the unit operation with the cooling mode charts
and procedures.
Before changing the unit charge, always inspect the following items fi rst:
1. Inspect the liquid line temperature on the inlet and outlet of the fi lter dryers. If it is the factory dryer and in good
condition there should be no temperature difference. If the
Δ
T is larger than 5˚, replace the fi lter dryer with one
that is bi-directional and has acid removal capability. Refer to the unit RPL for the recommended part number
and size.
2. Inspect the units input voltage. Units operating at less than 95% of the nominal voltage may deviate more from
the chart then previously stated.
3. Inspect the input voltage for a phase imbalance. Units with greater then a 2% disparity will not operate at the
rated performance.
4. Verify that the unit fi lters are installed and are clean. The pressure drop across the fi lters should not exceed 0.08
in-W.C.
5. Inspect the indoor coil, indoor blower and blower motor for cleanliness, clogging, and proper operation. Verify
the drive belt is in good condition and properly tightened.
6. Inspect the system for leaks. If a leak cannot be located the system charge is probably correct. Re-inspect the
return air and ambient temperatures and verify that the correct system point on the verifi cation chart was selected.
DO NOT
use the charts in systems that have the fan cycling under a low-ambient control. Low-ambient controls are
for cooling operation. In heating mode, the low ambient control should be disabled. Unless the unit is in defrost mode,
the outdoor fan should always operate in conjunction with the compressor.
Application Notes on the use of Heating-mode charge verifi cation charts:
