33
Fig. 30 — Fan Belt Tension
Fig. 31 — Fan Section Label
Water and Steam Coil Piping Recommendations
GENERAL
Use straps around the coil casing or the lifting holes (see Fig. 32)
to lift and place the coil.
Piping practices are outlined in the Carrier System Design Manu-
al, Part 3, Piping Design. See Tables -11 for circuiting data.
WATER COILS
Typically, coils are piped by connecting the supply at the bottom
and the return at the top. See Fig. 32. This is not always the case,
especially if the coil hand has been changed in the field. Coils
must be piped for counterflow; otherwise, a capacity reduction of
5% for each coil row will result. To ensure counterflow, chilled
water coils are piped so that the coldest water meets the coldest air.
Hot water coils are piped so that the warmest water meets the
warmest air.
STEAM COILS
Position the steam supply connection at the top of the coil, and the
return (condensate) connection at the bottom. The coil tubes must
incline downwards toward the return header connection for con-
densate drainage. See Fig. 33-37 and Table .
Figure 33 illustrates the normal piping components and the sug-
gested locations for high, medium, or low-pressure steam coils.
The low-pressure application (zero to 15 psig) can dispense with
the 1/4-in. petcock for continuous venting located above the vacu-
um breaker (check valve).
Fig. 32 — Coil Connections and Lifting Points
Note the horizontal location of the 15-degree check valve, and the
orientation of the gate/pivot. This valve is intended to relieve any
vacuum forming in the condensate outlet of a condensing steam
coil, and to seal this port when steam pressure is again supplied to
the coil. It must not be installed in any other position, and should
not be used in the supply line.
For coils used in tempering service, or to preheat outside air, in-
stall an immersion thermostat in the condensate line ahead of the
trap. This will shut down the supply fan and close the outdoor
damper whenever the condensate falls to a predetermined point,
perhaps 120°F.
CAUTION
To prevent damage to the coil or coil headers: Do not use the
headers to lift the coil. Support the piping and coil connections
independently. Do not use the coil connections to support pip-
ing. When tightening coil connections, use a backup wrench
on the nozzles.
50
100
1
50
SP
AN
INC
HES
1
5
20
2
5
30
50
10
0
1
50
SP
AN
IN
C
H
ES
05
10
15
20
25
30
5
0
10
0
1
50
S
P
AN
IN
C
H
ES
0
5
10
15
20
2
5
30
DEFLECTION
FORCE
(LB.)
SMALL
“O” RING
SPAN SCALE
STRAIGHT
EDGE
LARGE “O” RING
V-BELT
ADJACENT
V-BELT
BELT
SPAN
NOTICE
TENSION BELTS TO SPECIFICATION
SHOWN ON DRIVE LABEL. OVER
TENSIONING BELTS WILL SEVERELY
REDUCE BELT AND BEARING LIFE.
REPLACEMENT PARTS
BEARINGS
DRIVE ________________________
FREE _________________________
SHAFT _________________________
WHEEL _________________________
INLET CONE ____________________
TO ORDER REPLACEMENT PARTS,
CONTACT: RCD
(REPLACEMENT COMPONENTS DIVISION)
1-800-443-4410