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5.0 SYSTEM START-UP AND REFRIGERANT CHARGING
5.7 Indoor Air-Flow
Verification
Correct indoor air-flow and proper supply air
distribution is critical to system comfort, efficiency and
reliability. Excessive indoor air-flow results in elevated
humidity levels in the cooling mode and excessive air
noise. Low indoor air-flow reduces system capacity
and can result in coil icing and compressor failure in
the cooling mode and can cause nuisance high pres
-
sure switch tripping and increases power consumption
in the heating mode.
Fortunately, when the (-)A20 condensing units are
matched to the correct air-handler or furnace/coil
combination and are controlled by the communication
EcoNet
TM
Control Center, the indoor air-flow is auto
-
matically controlled to the proper level based on the
model data stored in the VSODC memory card. When
the indoor blower is operating, the EcoNet
TM
Control
Center will display the indoor CFM in the Service
Menu of the control. The approximate CFM is also
displayed in 100 CFM increments by a flashing LED on
the air-handler or furnace control board while the blow
-
er is operating (one flash per 100 CFM) for installations
where a conventional 24VAC thermostat is used.
Once the system is operating in the Charging Mode,
confirm the indoor CFM is close to those values in the
table below. If the displayed CFM is not reasonable
close to the value in the table, confirm cooling dehu
-
midification is disabled, the indoor air-flow trim adjust
-
ment is set to 0%, and verify the model numbers of
the indoor and outdoor units are an approved combi
-
nation by the manufacturer. Once the indoor air-flow
is verified, the indoor air-flow trim adjustment may be
changed to suit the installation and should be done
prior to final charge adjustment.
NOTICE:
AHRI rated CFM may differ slightly from
values in the table below.
Outdoor Unit
Model No.
Displayed Indoor
CFM Cooling Mode
(-) A2024A
840
(-) A2036A
1210
(-) A2048A
1565
(-) A2060A
1725
5.8 Refrigerant Charging
The refrigerant charge for all systems should be
checked against the Charging Chart located inside the
access panel cover.
WARNING:
The top of the scroll
compressor shell is hot. Touching the compressor top
may result in serious personal injury.
CAUTION:
R-410A pressures are
approximately 60% higher (1.6 times) than R-22
pressures. Use appropriate care when using this refrig
-
erant. Failure to exercise care may result in equipment
damage or personal injury. Charge for all systems
should be checked against the Charging Chart inside
the access panel cover.
IMPORTANT:
DO NOT
operate the
compressor without charge in the system.
Addition of R-410A will raise high-side pressures
(liquid and discharge).
NOTICE:
System maintenance is to be
performed by a qualified and certified technician.
The following method is used for charging the system.
All steps listed should be performed to ensure proper
charge has been set. For measuring pressures, the
service valve ports on the liquid service valve (small
valve) and the suction service valve (large valve) are to
be used.
The optimum refrigerant charge for any outdoor
unit matched with an indoor coil/air handler is affected
by the application. Refer to the charging chart inside
the access panel cover on the unit and choose the
appropriate column for the specific application being
installed or serviced. New installations utilizing either
an RCF indoor coil installed on a gas furnace or an
RHMV series air handler in the down flow or horizontal
right-hand discharge may require removal of some
refrigerant since the factory charge could result in an
overcharge condition.
Start Up
