AAON M2-036 - Manual (Page 53)

53
Draw-Through
Drain Pan Pressure Trap Dimensions
Negative Static X X/2
(inches of water) (inch) (inch)
-0.50 1.50 0.75
-1.00 2.00 1.00
-1.50 2.50 1.25
-2.00 3.00 1.50
-2.50 3.50 1.75
-3.00 4.00 2.00
-3.50 4.50 2.25
-4.00 5.00 2.50
-4.50 5.50 2.75
-5.00 6.00 3.00
-5.50 6.50 3.25
-6.00 7.00 3.50
-6.50 7.50 3.75
-7.00 8.00 4.00
-7.50 8.50 4.25
-8.00 9.00 4.50
Figure 19 - Blow-Through Drain Trap
The Y dimension of blow-through traps
should be at least equal to the value of the
positive pressure in the drain pan plus one
inch. This ensures that there will be enough
water stored in the trap to counter the static
pressure in the drain pan. To find the
pressure subtract any pressure drops
between the drain pan and the supply blower
from the blower discharge pressure. The
worst-case scenario for blow-through coils
is the minimum pressure drop, so do not
include dirt allowance pressure drops for
filters.
The bottom of the leaving pipe should be at
least one half inch lower than the bottom of
the drain pan connection. This ensures
proper drainage when the unit is not
running.
Note: It may be necessary to fill the trap
manually, or the trap can be filled
automatically by operating the unit until
enough condensate collects to fill the trap.
The trap will then be filled when the unit is
turned off.
Table 8 - Blow-Through Drain Trap
Dimensions
Blow-Through
Drain Pan Pressure Trap Dimension
Positive Static Y
(inches of water) (inch)
0.5 1.5
1.0 2.0
1.5 2.5
2.0 3.0
2.5 3.5
3.0 4.0
3.5 4.5
4.0 5.0
4.5 5.5
5.0 6.0
5.5 6.5
6.0 7.0
6.5 7.5
7.0 8.0
7.5 8.5
8.0 9.0
Blower Wheels
AAON units are equipped with a backward
curved blower wheels that is set to deliver
the air volume specified according to unit
size and/or job requirements.