Bryant GAS-FIRED 454 - Manual (Page 4)

Materials
1 . Chilled Water Piping
a. Use Bryant quick connect plastic hose.
b. Polyethylene pipe - satisfactory substi­
tute; use medium density flexible pipe
whose wall thickness approximates
Schedule 40 pipe (Commercial Standard
CS 255-63). Pipe must be made from
virgin material. Do not use pipe manu­
factured from re-claimed material.
c . Copper - satisfactory substitute .
d. Brass - satisfactory substitute.
2. Fittings
a. Galvanized - use when possible.
b. Brass - satisfactory substitute .
Pipe Length and Diameter
Table I shows the maximum length of pipe of
different diameters that can be used between
the pump discharge and the coil inlet and still
maintain minimum allowable (design) water
flow rate.
1. Multiply table values by two to obtain the
total length of pipe from chiller to coU and
return.
2. Length is measured along the pipe path
and therefore includes vertical distance be­
tween the water coil and the chiller.
3. Lengths shown in Table I are based on
using a total of eight well head fittings in the
entire water line (chiller to coil and return).
Lengths are predicated on the use of a Bryant
matching water coil. For greater distances
use larger size pipe.
4. For calculating chilled water pipe size for
coils not listed use friction loss method with
allowance for coil pressure loss. Refer to
coil instructions for pressure loss at design
water flow rate. Refer to Table II showing
available head with standard pump drive. For
additional pump head consult your Bryant
Distributor.
Insulation
1. Insulate both supply and return lines .
2. Material should be of good quality and be
covered with a good vapor barrier. Armaflex
or equivalent is recommended. Use 1/2-inch
wall thickness .(Plastic hose is pre-insulated.)
36/454
WATER FLOW RATE
AT VARIOUS EXTERNAL PRESSURES
Table II - Model 36-454
Water Flow Rate Pressure External to Unit
GPM Ft Water Std RPM
2.0 25.9
3.0 25.5
'4.0 25.0
5.0 24.5
6.0 23.8
7.0 23.0
7.5 22.5
8.0 22.0
9.0 21.0
10.0 19.7
11.0 18.6
Height of Coil above Unit
For the Model 36-454 the maximum vertical
distance from chiller to top of coil is 21 feet.
For greater heights an adjustable water pump
pulley kit is available, Part No. 65070D01.
Water Coil Connections
1. If the cooling coil is used in connection
with a heating unit and the heating unit is not
approved for installation downstream from
the cooling coil, install the cooling coil in
parallel with or downstream from the heating
unit. This will avoid condensation in the heat­
ing unit. If the coil and heating unit are in­
stalled in parallel, the dampers or other
means used to control flow of air should be
adequate to prevent chilled air from entering
the heating unit; if manually operated, the
dampers shall be equipped with some means
to prevent operation of either unit uiiless the
dampers are in full heat or full cool position.
2. If the coil is located in a warm air stream,
do not connect polyethylene pipe directly to
the coil. Connect a minimum of 24 inches of
copper or galvanized pipe to both the coil in­
let and outlet; then connect the polyethylene
pipe to these nipples . Note: not required when
using Bryant quick connect plastic hose.
3. On installations where the water in the
outside piping freezes and the coil is in a
heated air stream, precautions must be taken
to provide for water expansion. The connect­
ing polyethylene pipe acts as an expansion
vessel if there is sufficient footage in the
-
4
-