Trane GXAA, Installation, Operation And Maintenance Manual

Page: 28 / 64

28 MUA-SVX006B-EN
• The DX Coil has a 300 ft/min. (1.524 m/s) minimum and a 600 ft/min. (3.048 m/s) maximum
velocity through the coil requirement. This is due to prevention of coil icing or condensate
blow-off. To calculate the velocity through the coil, apply the following formula:
• Condensate Drain piping must have a P-trap in line immediately downstream of drain pan
connection, external to the unit, to prevent possible outside air leakage into unit. The P-trap
shall be of sufficient differential to overcome negative pressure of the indoor air blower. A
minimum height difference of 2" (51mm) is required (See
Figure 20, p. 28 ). Before unit
operation begins, the P-trap must be primed with either water (summer) or glycol (winter).
Chilled Water Coil Equipped Units (Optional)
See Coil Installation/Maintenance Manual for General Coil Piping Recommendations. Remove
the coil cabinet door and cut holes in door to allow chilled water piping passage. Provide
weatherproof seal around chilled water pipes at piping plate when installed.
The Chilled Water Coil has a 600 ft/min (3.048 m/s) maximum velocity through the coil
requirement. This is due to prevention of condensate blow-off. To calculate the velocity through
the coil apply the following formula:
Condensate Drain piping must have a P-trap in line immediately downstream of drain pan
connection, external to the unit, to prevent possible outside air leakage into unit. The P-trap shall
be of sufficient differential to overcome negative pressure of the indoor air blower. A minimum
height difference of 2 inch is required (See
Figure 20, p. 28 ). Before unit operation begins, prime
P-trap with either water (summer) or glycol (winter).
Evaporative Cooler Equipped Units (Optional)
Refer to Evaporative Cooler Installation and Service Manual for water and electrical connections.
Figure 20. Drain Pan Connection
H
Total
Height
of Trap
Total Height Of Trap = X+ H + (1-1/2 X Pipe Diameter)
(without Insulation)
Unit
Housekeeping
Pad
X
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