Typical Field Wiring; Electrical Connections; R-410A Saturation Properties - York YZF Installation Manual

CHARGING IN HEATING MODE
If charging in heating mode, there are two methods for charging:
Weighing in the charge is the best method for ensuring the unit per-
forms as rated. However, if a device is installed in the line set that alters
the amount of refrigerant, such as a refrigerant flow meter, then the bet-
ter method for charging is to match the liquid pressure from the heating
charging chart (if available) or heating service data (available from
wwwupgnet.com). If no such device exists in the line set, then the
method is acceptable if weighing in the charge is not an option.
If servicing a unit for low heating performance and you find that you
have to add a significant amount of charge (ex: 20-30 ounces) in order
to match the published liquid pressures, the unit will NOT be over-
charged in cooling. Heat pumps are sensitive to charge in heating, but
not in cooling.
CHARGING WITH GAUGES
Refrigerant charging should only be carried out by a qualified air con-
ditioning contractor.
Do not charge a heat pump in cooling mode with gauges or charging
charts or any other method other than weighing in the charge.
Compressor damage will occur if system is improperly charged. On
new system installations, charge system per tabular data sheet for
the matched coil and follow guidelines in this instruction.
However for servicing a heat pump unit, the charging charts are an
acceptable troubleshooting method, but when the servicing is com-
pleted, the charge should be reclaimed and weighed in (to guarantee
optimal performance in heating mode). If servicing in heating mode, the
charge does not have to be reclaimed if the liquid pressures match the
published values.
Before measuring the pressures, use the method above to check the air
flow and then consult the table and match the liquid pressure to that air
flow.
Before servicing a unit, confirm that your gauges are accurate by
comparing the gauges against a calibrated pressure gauge that has
been calibrated against a national standard. If a calibrated pressure
gauge is not available, place a R-410A virgin refrigerant container in a
conditioned space long enough to come to temperature equilibrium with
the surroundings. Then measure the temperature of the air and the
pressure of the refrigerant and compare it to the following table:
:
TABLE 2: R-410A Saturation Properties
Temp Pressure Temp
(°F) (Psig) (°F)
40 119 75
45 130 80
50 143 85
55 156 90
60 170 95
65 185 100
70 201 105
Johnson Controls Unitary Products
Pressure Temp Pressure
(Psig) (°F) (Psig)
218 110 365
236 115 391
255 120 418
274 125 447
295 130 477
317
341
If the gauges are correct, then measure the pressures using both
the cooling and heating charts.
SECTION VII: ELECTRICAL
CONNECTIONS
GENERAL INFORMATION & GROUNDING
Check the electrical supply to be sure that it meets the values specified
on the unit nameplate and wiring label.
Power wiring, control (low voltage) wiring, disconnect switches and over
current protection must be supplied by the installer. Wire size should be
sized per NEC requirements.
All field wiring must USE COPPER CONDUCTORS ONLY and be in
accordance with Local, National Fire, Safety & Electrical Codes. This
unit must be grounded with a separate ground wire in accordance
with the above codes.
The complete connection diagram and schematic wiring label is located
on the inside surface of the unit service access panel and this instruc-
tion.
FIELD CONNECTIONS POWER WIRING
1. Install the proper size weatherproof disconnect switch outdoors and
within sight of the unit.
2. Remove the screws at the bottom of the corner cover. Slide corner
cover down and remove from unit. See Figure 5.
3. Run power wiring from the disconnect switch to the unit.
4. Remove the service access panel to gain access to the unit wiring.
Route wires from disconnect through power wiring opening provided
and into the unit control box.
5. Install the proper size time-delay fuses or circuit breaker, and make
the power supply connections.
6. Energize the crankcase heater if equipped to save time by preheat-
ing the compressor oil while the remaining installation is completed.
Service
Access
Panel
Control
Wiring
Power
Wiring
Ambient
Temperature
Sensor
FIGURE 5: Typical Field Wiring
835966-UIM-E-0814
Corner
Cover
A0203-001
7