Trane UniTrane Fan-Coil & Force Flo Air Conditioners manual Steam Piping, mechanical, Coil Damage

mechanical

Installation requirements

Steam Piping

CAUTION

Coil Damage!

In all steam coil installations, the condensate return connections must be at the low point of the coil to ensure condensate flows freely from the coil at all times. Failure to do so may cause physical coil damage from water hammer, unequal thermal stresses,freeze-up and/or corrosion.

1.Make piping connections to the steam coil as shown in Figure I-MR-11. Cap the unused connection.

2.The coil is already pitched within the unit to provide proper pitch to drain condensate out of the coil. Verify that the unit has been properly leveled.

3.Install a 1/2-inch, 15-degree swing check vacuum breaker in the unused condensate return tapping as close as possible to the coil.

4.Vent the vacuum breaker line to atmosphere or connect it into the return main at the discharge side of the steam trap.

5.Pitch all steam supply and return mains down a minimum of one inch per ten feet in the direction of flow.

6.Do not drain the steam mains or take- off through the coils. Drain the mains ahead of the coils through a steam trap to the return line.

7.Overhead returns require one psig of pressure at the steam trap discharge for each two-feet elevation to ensure continuous condensate removal.

8.Proper steam trap selection and installation is necessary for satisfactory

coil performance and service life. For installation, use the following steps: a. Position the steam trap discharge at least 12 inches below the condensate

return connection. This provides sufficient hydrostatic head pressure to overcome trap losses and ensure complete condensate removal.

Figure I-MR-2. Typical Piping for Steam Coils

b. Trane recommends using flat and thermostatic traps because of gravity drain and continuous discharge operation.

c. Use float and thermostatic traps with atmospheric pressure gravity condensate return, with automatic controls or where the possibility of low pressure supply steam exists.

d. Always install strainers as close as possible to the trap inlet side. Reference Figure I-MR-10 for an example of a properly piped steam coil.

Code of System Components in Piping Diagram

FT	Float and thermostatic steam trap
BT	Bucket steam trap
GV	Gate valve
OV	Automatic two-position (on-off) control valve
TV	Automatic three-way control valve
VB	Vacuum breaker
CV	Check valve
ST	Strainer
AV	Automatic or manual air vent

vacuum breaker (if desired)

steam supply

plugged

condensate return

Figure I-MR-11. Main steam coil connection diagram

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