Ruud ANL-AZ 13 SEER Series, Installation Instructions Manual

23

With an accurate scale (+/– 1 oz. [28.3 g]) or 

volumetric charging device, adjust charge 

difference between that shown on the unit data 

plate and that calculated for the new system 

installation� If the entire system has been 

evacuated, add the total calculated charge�

IMPORTANT:

 Charging by weight is  

not always accurate since the application can 

affect the optimum refrigerant charge� Charging by 

weight is considered a starting point ONLY� Always 

check the charge by using the Charging Chart 

and adjust as necessary� CHARGING BY LIQUID 

SUBCOOLING MUST BE USED FOR FINAL 

CHARGE ADJUSTMENT�

With thermostat in the “Off” position, turn on the 

power to the furnace or air handler and the heat 

pump� Start the heat pump and the furnace or air 

handler with the thermostat� Verify that the outdoor 

unit is operating in second stage and the indoor 

air mover is delivering the second-stage airflow for 

the system size�

Gross Charging by Pressures

1� Following airflow verification and charge weigh-

in, run the unit for a minimum of 15 minutes 

prior to noting pressures and temperature�

IMPORTANT:

 Indoor conditions 

as measured at the indoor coil must be within 

2°F [1.1°C] of the following during gross charge 

(pressure) evaluation:

Cooling Mode: 80°F [26.7°C] Dry Bulb
Heating Mode: 70°F [21.1°C] Dry Bulb

NOTICE:

 If the Indoor temperature is above  

or below this range, run the system to bring the 

temperature down or run the electric heat/furnace 

to bring the temperature within this range� System 

pressure values provided in the Charging Chart for 

outdoor dry bulbs corresponding to conditions outside 

of these ranges are provided as reference ONLY� 

2� Note the Outdoor Dry Bulb Temperature, 

ODDB° = _____°F [_____°C]� Unit charging is 

recommended under the following outdoor 

conditions ONLY:
Cooling Mode ONLY: 55°F [12.8°C] outdoor dry 

bulb and above
Heating Mode ONLY: Between 40°F [4.4°C] and 

60°F [15.6°C] outdoor dry bulb

3� Locate and note the design pressures� The 

correct liquid and vapor pressures are found at 

the intersection of the installed system and the 

outdoor ambient temperature on the Charging 

Chart located inside the access panel cover� 
Liquid Pressure: = ______psig; Vapor Pressure = 

______psig

NOTICE:

 The refrigerant pressures provided 

are for gross 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� 

Note that all systems have unique pressure curves� 

The variation in the slope and value is determined 

by the component selection for that indoor/outdoor 

matched system� The variation from system to 

system seen in the table is normal� The values listed 

are for the applicable indoor coil match 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, 

remove charge� 

Final Charge by Subcooling

1� After gross charging, note the designed 

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].

IMPORTANT:

 Indoor conditions as 

measured at the indoor coil are required to be 

between 70°F [21.1°C] and 80°F [26.7°C] dry 

bulb for fine-tuned unit charge adjustment� Unit 

charging is recommended under the following 

outdoor conditions ONLY:

Cooling Mode ONLY: 55°F [12.8°C] outdoor dry 

bulb and above
Heating Mode ONLY: Between 40°F [4.4°C] and 

60°F [15.6°C] outdoor dry bulb

START-UP

Checking Refrigerant Charge (cont�)

Refrigerant