Coil Piping and Connections
CLCH-SVX009J-EN 39
Steam Coil Piping
Air handlers fitted with steam coils have labeled holes for
piping penetrations. Figure 46 illustrates a typical steam
coil piping configuration. See Table 9 for the codes of
system components in these figures.
The coil condensate return line must be piped full size of
the condensate trap connection, except for a short nipple
screwed directly into the coil header’s condensate return
tapping. Do not bush or reduce the coil return trapping
size.
Figure 45. Drain pan trapping for negative and positive pressure applications
H
J
L
Section under negative pressure
L = H + J + pipe diameter where:
H = 1 inch for each inch of negative
pressure plus 1 inch
J = 1/2 H
Section under positive pressure
L = H + J + pipe diameter where:
H = 1/2 inch (minimum)
J = 1/2 inch plus the unit positive
static pressure at coil discharge
(loaded filters)
Table 9. Code of system components for piping figures
Code System component
FT Float and thermostatic steam trap
GV Gate valve
OV Automatic two-position (ON-OFF) control valve
VB Vacuum breaker
ST Strainer
AV Automatic or manual air vent
MV Modulating control valve
Figure 46. Typical piping for Type NS steam coils and
horizontal tubes for horizontal airflow
Pitch down
VB
GV
GV
VB
GV
MV
ST
Steam main
Full size
of main
ST
Full size
of coil
connection
ST
12 in. min.
Return main
12 in. min.
FT
FT
Full size of
steam trap
connection
FT
ST
Airflow
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