5
MODEL
INDOOR
CASED COILS
600 700
800
900 1000 1100
1200
1300
1400
1500
1600
1700
1800 1900
AC1A024A
.10
.11
.12
.13
AC1A030A
.15
.17
.19
.21
AC1A036A
.19
.20
.22
.23
.24
AC1A042A
.15
.17
.18
.21
AC1A060A
.21
.23
.23
STATIC PRESSURE DROP
THROUGH DRY COIL* & HOUSING (INCHES WATER COLUMN / CFM)
CHECK AND ADJUST AIRFLOW
Check that the correct amount of air is flowing through the
coil by measuring the pressure drop using an air flow gauge.
Checking Static Drop Across Coil
1.
The coil should be dry and clean. The air filter must be
clean and all registers open. Do not run the condensing
unit when checking air flow.
2. Run the Blower on cooling speed.
3. Set the blower motor speed-belt drive or direct drive to
the nominal CFM required across coil and the dry coil
static reading. See chart below.
Adjusting Air Flow
If gauge reading is below the required pressure, increase
blower speed until reading is the same or slightly above the
required pressure.
If the gauge reading is above required pressure, decrease the
blower speed.
Refer to instructions included with your furnace or blower for
directions on changing blower speed.
NOTE:
You may not be able to obtain a gauge reading exactly
the same as the required pressure due to variations in duct
systems and blower speeds.
A slightly high reading is acceptable.
A low reading will indicate conditions that could cause a
freeze up. This will shorten compressor life. Too much air will
result in poor humidity control and overheating of the
compressor. It may cause tripping of the compressor overload.
If you are using a belt driven blower, use an ammeter to check
the motor current draw. If the current draw is higher than the
motor name plate amps, replace the motor with one with
greater horsepower.
* Dry coil static shown. Increase static by 20% for wet coil static.
