5.0 SYSTEM START-UP AND REFRIGERANT CHARGING
The refrigerant pressures
provided are for preliminary charge check ONLY.
These pressure values are typical, but may vary
due to application. Evaporator load (indoor coil in
cooling mode/outdoor coil in heating mode) will cause
pressures to deviate. The values listed are for the
correct matched indoor coil ONLY!
4. If the measured liquid pressure is below the
listed requirement for the given outdoor and
indoor conditions, add charge. If the measured
liquid pressure is above the listed requirement
for the given outdoor and indoor conditions,
5.8.4 Final Charging by Liquid
1. After preliminary charging by weight or
pressures, find the design subcooling value.
The correct subcooling value is found at the
intersection of the installed system and the
outdoor ambient temperature on the Charging
Chart located inside the access panel cover.
SC° from Charging Chart = _____°F [_____°C].
as measured at the indoor coil are required to
be within 2ºF (1.1ºC) of comfort conditions as
preferred by the homeowner and must have
operated for at least 15 minutes prior to final
charge adjustment. Unit charging is recommended
under the following outdoor conditions ONLY:
Cooling Mode: 55°F [12.8°C] outdoor dry bulb
Heating Mode: Between 40°F [4.4°C] and 60°F
[15.6°C] outdoor dry bulb
5.8.5 R-410A Temperature
Systems should not be charged
below 40°F [4.4°C] outdoor temperature.
If the indoor temperature is
above or below the recommended range, run the
system to bring the temperature down or run the
electric heat/furnace to bring the temperature up.
2. Note the measured Liquid Pressure, Liq Press =
______psig, as measured from the liquid (small)
service valve. Use the Temperature Pressure
Chart below to note the corresponding saturation
temperature for R-410A at the measured liquid
Liquid Saturation Temperature, SAT°= _____°F
3. Note the liquid line temperature, Liq° = _____°F
[_____°C], as measured from a temperature
probe located within 6" [15.2 cm] outside of
the unit on the copper liquid line (small line).
It is recommended to use a calibrated clamp-
on temperature probe or an insulated surface
4. Subtract the liquid line temperature from the
saturation temperature to calculate subcooling.
SAT°_____°F [_____°C] - Liq°_____°F [_____°C]
= SC°_____°F [_____°C]
5. Adjust charge to obtain the specified subcooling
value. If the measured subcooling level is below
the listed requirement for the given outdoor
temperature, add charge. If the measured
subcooling level is above the listed requirement
for the given outdoor temperature, remove
• Disconnect the hoses from the pressure ports.
Replace the pressure port caps and tighten
adequately to seal caps. DO NOT overtighten.
• Replace the service valve top caps finger-tight and
then tighten with a wrench to adequately seal caps.
DO NOT overtighten.
• Replace control box cover and service panel and
install screws to secure panels.
• Restore power to unit at disconnect if required.
• Exit Charging Mode and configure Digital Control
Center or thermostat per the thermostat installation
instructions and set to desired mode and