Installation manual

Page 30 IM-487
2. Float and thermostatic or bucket traps are recommended
for low pressure steam. Use bucket traps on systems with
on-off control only.
3. Locate traps at least 12 inches (305 mm) below the coil
return connection.
4. Always install strainers as close as possible to the inlet
side of the trap.
5. A single trap may generally be used for coils piped in par-
allel, but an individual trap for each coil is preferred.
Figure 31. Heating Coil Piping With Vestibule
Freeze Conditions Steam Coils
Entering air temperature below 35°F (2°C)
1. 5 PSI (34.5 kPa) steam must be supplied to coils at all
times.
2. Modulating valves are not recommended. Use face and
bypass dampers.
3. As additional protection against freeze-up, install the trap
sufficiently far below the coil to provide an adequate
hydrostatic head to remove condensate during an interrup-
tion on the steam pressure. Estimate 3 feet (914mm) for
each 1 PSI (6.9 kPa) of trap differential required.
4. If the unit is to be operated in environments with possible
freezing temperatures, an optional freezestat is recom-
mended. Refer to "Freeze Protection" in the "Unit
Options" section of this manual.
Chilled Water Piping
Chilled water coils are provided without valves for field pip-
ing, or piped with three-way valves with motor actuators.
Table 8 provides information on units with factory installed
piping and valve packages. The table also provides field
sweat connection information for units not furnished with
factory installed piping and valve packages.
With the factory piping and valve package, the coil assembly
is controlled through a single three-way valve. When two
coils are included in the assembly, they are piped in parallel.
Field connections are male NPT, sized as shown in Table 8.
Refer to Figure 32 for a typical cooling coil with factory
valve and piping.
Figure 32. Chilled Water Coil
(Shown With Factory Valve and Piping)
Air Flow
Bypass
Supply
Return