Greenheck Coils - Manual (Page 3)

Page 3 of 7 IOM, Rev. 2, November 2007
Copyright © Greenheck Fan Corporation
Steam Coil Installation Recommendations
A. General
1. Provide separate supports and hangers for the coil and for the piping. Always use a back up wrench
on coil connections when attaching piping to the coil. Coils not designed with pitched casing or fin
pack must be pitched ¼" per foot towards the return connection at installation.
2. Be certain that adequate piping flexibility is provided. Stresses resulting from expansion of closely
coupled piping and coil arrangement can cause serious damage.
3. Do not reduce pipe size at the coil return connection. Carry the return connection size through the dirt
pocket, making the reduction at the branch leading to the trap.
4. Vacuum breakers and air vents must be installed on all applications to prevent retaining condensate
or air in the coil. Generally the vacuum breaker is to be connected between the coil inlet and the trap.
For a system with a flooded return main, the vacuum breaker should be open to the atmosphere and
the trap design should allow venting of large quantities of air.
5. Do not drip steam mains through coils.
6. Insure steam pressure and condensate line pressure differential is sufficient to allow efficient
condensate removal from the steam coil, especially when using modulating steam control valves to
control the leaving air temperature of the coil.
7. Do not attempt to lift condensate without the assistance of a condensate pump. The pressure
required to lift condensate must also be considered for sufficient pressure differential. Check valves
are also required to prevent reverse flow of condensate back into the coil.
8. Entering air temperatures should not be below 40° F to insure freezing doesn't occur.
B. Traps
1. Size traps in accordance with the manufacturer’s recommendations. Be certain that the required
pressure differential will always be available. Do not undersize.
2. Float and thermostatic traps are recommended for high or low-pressure steam systems, but bucket
traps may be used. Float and thermostatic traps should be used when air venting is necessary.
Bucket traps are recommended for use with on-off control only. It is recommended that traps be
located at least 12 inches below the coil return connection. When traps without air venting capabilities
are used, air vents are required in the system.
3. Multiple coil installations:
a. Each coil or group of coils that is individually controlled must be individually trapped.
b. Coils in series; separate traps are required for each coil, or bank of coils, in series.
c. Coils in parallel; a single trap may be used but an individual trap for each coil is preferred.