Reznor CAUA Unit Installation Manual - Manual (Page 33)

Form I-CAUA, P/N 164771 R8, Page 33
Condensate Drain Trap The design of the drain trap is important. If dimension "B" in FIGURE 26A is not tall
enough, the water seal will not hold, and air will be drawn through the drain pipe into
the system. If the outlet leg of the trap is too tall, water will back up into the drain pan.
As condensate forms during normal operation, the water level in the trap rises until
there is a constant outflow. FIGURE 26B illustrates the appropriate dimensions.
To prevent air
from entering
always close
the cleanout.
Water Flow
Unit
FIGURE 26B -
Drain Trap with
Cleanout
B
A
A/2
C
L
C
L
C
L
Unit
Water Flow
Water Flow
A = 3" (76mm)
minimum
B = A + A/2
FIGURE 26A -
Condensate
Drain Trap
Dimensions
Coil Condensate Drain
Use
Improper trap design accounts for some condensate drainage system failures, but
incorrect use and maintenance of condensate drain traps can also cause problems.
The combination of airborne particles and moisture in the air handler can result in
algae formation in the drain pan and traps. The traps must be cleaned regularly to
avoid blockage that can slow or stop water flow, resulting in backup into the system.
If drains have a cleanout opening ( FIGURE 26B), be sure to close the opening after
cleaning.
Seasonal Usage - At the beginning of the cooling season, inspect and clean the entire
cooling coil cabinet including the condensate drain pan. Thoroughly clean dirt, algae,
grease, and other contaminates. Inspect condensate drain pans, traps, and piping; fill
traps with water to ensure proper operation. During a wintertime shutdown of the cool-
ing system it may be desirable to disconnect and remove all water from the traps and
drains to prevent freeze damage. If local building codes permit, traps may be filled with
an antifreeze solution. Or, piping may be designed with freeze plugs or other freeze
protection methods (such as a heat tape).
Year Round Usage - Climates or applications with cooling requirements year round
require more frequent inspections of the cooling coil cabinet and condensate drains.
Depending on climate, freeze protection of traps may be required during non-cooling
hours.
6.7 Burner
Condensate
Drain
If an optional cooling coil is installed on a Model CAUA heater (either now or at a later
time), a burner condensate drain line must be installed.
The parts to install the drain line are packaged and shipped with all Model CAUA
heaters.
TABLE 25 -
Burner
Condensate
Drain
Components
Qty P/N Description
1 165955 6-ft length of 3/8" I.D. Tubing
1 165952 90° Nylon Fitting, 1/4" NPT x 3/8" tubing
1 110628 1/4" NPT Brass Nut
1 171527 1/4" Locknut, Hex, T& B 139
1 165953 Sealing Washer
2 20913 Nylon Wire Ties, T&B #TY-24M
1 87556 Snap Bushing, Heyco SB 625-8
Instructions for
Installing Burner
Condensate Drain
1. Remove the burner compartment door.
2. The burner box cover is in two or three sections. On the left side of the burner
box cover, disconnect the flame sensor wire and the flame rollout switch wires.
Disconnect the silicone tubing from the static tap. Remove the left section of the
burner box cover.
3. Determine which side of the cabinet will be most convenient for the drain line. On
that side, remove the hole plug. Insert the snap bushing provided.