5284792-UIM-A-0317
Johnson Controls Unitary Products
9
TOTAL SYSTEM CHARGE DETERMINED
1. Determine outdoor unit factory charge from Tabular Data Sheet.
2. Determine indoor coil adjustment (if any) from Tabular Data Sheet.
3. Calculate the additional charge for refrigerant piping using the Tabu-
lar Data Sheet if line length is greater than 15 feet (4.6 m).
4. Total system charge = item 1 + item 2 + item 3.
5. The manifold gauge set is already installed on the unit for evacua-
tion and charging. Use these gauges to initially charge the system
using system pressures and subcooling. You will find the charging
information printed on the bottom of the unit data tag. More charging
information is available in the “Service Data Application Guide”,
available online. For subsequent annual maintenance visits the
charge verification display can be used to quickly check overall sys-
tem condition and the system charge without attaching a separate
manifold gauge set or temperature sensors.
6. Permanently mark the unit data plate with the total amount of refrig-
erant in the system.
CHARGE VERIFICATION MODE
The outdoor display will assist the installer with charging the system.
Through interaction with the Outdoor Display the system will operate at
predetermined nominal speed values. During this operation the system
will monitor pressures and temperatures. When the subcooling is within
the predetermined values set by the OEM, the outdoor display will indi-
cate SYSTEM CHARGE VALIDATED. This mode is only available
when the ID temperature is within 73 to 83°
F and humidity is less than
73% as measured by the Hx
TM
thermostat. Operation will continue but
charge will not be verified.
User Interaction/Operation:
1. Press Menu, press Arrow until Modes is displayed, press Select.
Press Arrow until Charge Verification is displayed, press Select.
2. Press Select while in Charge Verification Mode. The system will
detect the Unit Type and Unit Tonnage. The outdoor display will
update and scroll text, see the example below.
Example:
4-TON AC FOUND * VERIFY CHARGE? * 4-TON AC
FOUND * VERIFY CHARGE?
3. Press Select to verify charge, the outdoor display will update and
scroll text, see the example below.
Example:
VERIFYING CHARGE * PLEASE WAIT * VERIFYING
CHARGE * PLEASE WAIT
(5 minute wait time during initial charge calculation)
4. ADD CHARGE or REMOVE CHARGE will display on the banner
with the appropriate response dependent upon the OEM's predeter-
mined values, user may press Select when the banner displays
ADD CHARGE or REMOVE CHARGE. The display will indicate
ACCEPTED for 5 seconds and return to the example defined in
Step 1. However, if the system does meet the charge requirements
defined by the OEM, the outdoor display will indicate the below text
example for 5 seconds and return to the text example in Step 2 until
charge verification has fully completed.
Example:
SYSTEM CHARGE VALIDATED
The system will repeat steps 1-3 until the subcooling has reached the
predetermined values set by the OEM.
5. Once charge verification is fully complete the outdoor display will
return to the Second Menu Layer.
SECTION VII: SYSTEM OPERATION
ANTI SHORT-CYCLE DELAY
The control includes a five-minute anti short-cycle delay (ASCD) timer
to prevent the compressor from short-cycling after a power or thermo-
stat signal interruption. The ASCD timer is applied when the control is
first powered and immediately following the completion of a compressor
run cycle. The compressor and the outdoor fan will not operate during
the five minutes that the timer is active.
LOW VOLTAGE DETECTION
The control monitors the outdoor transformer secondary (24 VAC) volt-
age and provides low voltage protection for the heat pump and its com-
ponents. If the voltage drops below approximately 22 VAC, the control
continues to energize any outputs that are already energized. If the volt-
age drops below approximately 19 VAC, the control immediately de-
energizes the outputs and can no longer energize any outputs until the
voltage level increases above 22VAC. The control stores and displays
the appropriate fault codes when low voltage conditions occur.
TEST MODE OPERATION
Test mode operation provides the features found in Table 3 to assists in
unit commissioning and troubleshooting. TEST MODE is accessed
through the Outdoor Display. Please see Page 11 for detailed Outdoor
Display operation.
WARNING
DO NOT attempt to pump “Total System Charge” into outdoor unit for
maintenance, service, etc. This may cause damage to the compres-
sor and/or other components. Recover and weigh “System Charge”
into an appropriate recovery cylinder for any instances requiring
evacuation.
CAUTION
It is unlawful to knowingly vent, release or discharge refrigerant into
the open air during repair, service, maintenance or the final disposal
of this unit.
FIGURE 10:
Main Outdoor Control and Display
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