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CH35 SERIES
ABOVE
FINISHED
SPACE?
OVERFLOW DRAIN LINE
ALWAYS RUN AN OVERFLOW DRAIN LINE. IF NOT POSSIBLE TO
ROUTE OVERFLOW DRAIN LINE, INSTALL LOW VOLTAGE
OVERFLOW SWITCH KIT. WIRE KIT TO SHUT DOWN
COMPRESSOR PER INSTRUCTIONS.
NO
YES
CATALOG#
X3169
CLEAN OUT
VENT
PRESS IN
(DO NOT GLUE)
VENT MUST EXTEND
ABOVE HEIGHT OF
COIL DRAIN PAN BY
TWO INCHES
1” X 3/4” X 3/4”
REDUCING
TEE WITH
PLUG
CATALOG
NUMBERS* —
P-TRAP - 49P66,
J-TRAP - 91P90 OR
ANY PVC SCH 40 P-
OR J-TRAP 3/4”
OVERFLOW
DRAIN
OPTIONAL
SAFETY
PAN
COIL DRAIN PAN
WHEN A COIL IS LOCATED ABOVE A FINISHED SPACE, A 3/4” SECONDARY DRAIN LINE
MUST BE:
● CONNECTED TO SECONDARY DRAIN PAN OR
● CONNECTED TO THE OVERFLOW DRAIN OUTLET OF THE AIR HANDLER DRAIN PAN.
TRAPS MUST BE DEEP ENOUGH TO OFFSET MAXIMUM STATIC DIFFERENCES —
GENERALLY, TWO INCHES.
DRAIN LINE SHOULD
SLOPE A MINIMUM OF
ONE INCH PER 10 FT.
NOTE
— WHEN A AIR HANDLER IS LOCATED ABOVE A FINISHED SPACE THE SECONDARY
DRAIN PAN MUST HAVE A LARGER FOOTPRINT THAN THE AIR HANDLER.
MAIN
DRAIN
TO APPROVED
DRAIN
FOR NEGATIVE PRESSURE COILS (BLOWER
AFTER COIL), TRAPS ARE REQUIRED ON ALL
DRAIN LINES CONNECTED TO COIL.
COMPACT OVERFLOW SWITCH WITH 3/4” FEMALE SLIP INLET
AND MALE ADAPTER, TWO-PART DESIGN FOR USE WHERE
OBSTRUCTIONS PREVENT DIRECT THREADING
SECONDARY
DRAIN PAN
2”
(51MM)
TRAP DEPTH
*P-TRAP 49P66 REQUIRES A LARGER INSTALLATION SPACE THAN THE J-TRAP 91P90.
Figure 10. Typical Main and Overflow Drain Installations
Blower Speed Connection
Proper air volume must be provided over the evaporator
coil. Select a blower motor speed tap that will provide 400 ±
50 CFM per 12,000 Btuh of cooling capacity (wet coil).
A static pressure reading must be taken to see if the
pressure drops are within the proper range. See figure 11
as an example to obtain an accurate reading.
To ensure accuracy, test the air on both sides of the coil.
Refer to figure 11 for location of two test holes.
LEFT-HAND AIR DISCHARGE (TOP VIEW)
SUPPLY AIR UNIT FRONT
SUPPLY AIR UNIT REAR
AIR
FLOW
TEST HOLE 1
TEST HOLE
2
SUPPLY
AIR DUCT
RETURN AIR
DUCT
Figure 11. Static Pressure Test
CAUTION
Take care when drilling test holes into the furnace flange
and the duct. Drill holes away from refrigerant piping.
Test holes should be drilled where specified in order to
avoid unit damage.
1. Drill a 5/16" test hole in the coil case 1" from the
furnace flange (test hole 1, figure 11).
2. Drill a 5/16" test hole into the supply air duct (test hole
2, figure 11).
3. Connect the zero end of the draft gauge scale to the
furnace end of the coil. Insert the hoses so that 1/4"
extends inside the duct or end seal. Seal around holes
with Permagum.
4. Turn on the electrical power to the furnace and set the
thermostat to initiate a cooling demand.
