Specifications

2-49
JOHNSON CONTROLS
FORM 102.20-N1 (1109)
2
Steam Traps
Float and Thermostatic (F and T) traps are recommended
for all low or medium pressure applications. Use
thermostatic traps only for air venting, for outdoor
applications where an F and T trap might be subject to
freezing. Use bucket traps only for a non-modulated
steam supply. Size the steam traps in accordance with
the manufacturer's recommendations (usually several
times the steady state steam ow). Use the actual
operating conditions (coil pressure vs. return pressure)
for the selection of a trap.
It is preferable to provide an individual trap for each
coil but a single trap may be used for coils operating in
parallel with respect to the airow. Coils in series with
respect to airow must be supplied with individual traps.
Locate the trap at least 12 inches below the coil return
connection and even lower when freeze protection is
required. Do not attempt to lift condensate modulated
steam supply.
FIG. 2-71 – STEAM COIL PIPING ARRANGEMENTS
VENT TO
ATMOSPHERE
CLOSE TO
UNIT
(NOT ON
VACUUM
SYSTEMS)
DRIP TRAP
FOR END
OR LOW
POINT OF
SUPPLY
MAIN
SUPPLY MAIN
RETURN
MAIN
STEAM COIL
PITCHED IN CASING
12" MIN.
DIRT
POCKET
(FULL
SIZE OF
COIL
CONN.)
VACUUM
BREAKER
1/2" CHECK
VA LVE
(OPTIONAL)
SYMBOLS FOR "SS" STEAM
COIL PIPING ARRANGEMENTS
GATE VALVE
STRAINER
CONTROL VALVE
(MODULATING OR
TWO POSITION)
VACUUM
BREAKER
1/2" CHECK
VA LVE
(OPTIONAL)
CHECK VALVE
FLOAT AND
THERMOSTATIC
TRAP
12" MIN.
DIRT POCKET
(FULL SIZE OF
COIL CONN.)
F & T
TRAP
RETURN MAIN
PITCHED IN CASING
STEAM COIL
SUPPLY MAIN
SINGLE COIL
VERTICAL AIR FLOW
SUPPLY MAIN
12" MIN.
12" MIN.
RETURN MAIN
COILS IN SERIES
AIR FLOW MUST HAVE
INDIVIDUAL TRAPS AND
CONTROL VALVES
AIR FLOW
AIR FLOW
RETURN MAIN
12" MIN.
COILS IN PARALLEL AIR FLOW
MAY HAVE COMMON SUPPLY
AND SINGLE TRAP
(INDIVIDUAL COIL TRAP PREFERRED)
SUPPLY
MAIN
LD04887A