Table of Contents
Advertisement
NOTES:
1. Flange or union is located to facilitate coil removal.
2. When control valve is omitted on multiple coils in parallel air
flow.
3. When a bypass with control is required.
4. Coils with different pressure drops require individual traps.
This is often caused by varying air velocities across the
coil bank.
Fig. 29 — Multiple Coil Low Pressure
Piping Gravity Return
NOTES:
1. Flange or union is located to facilitate coil removal.
2. To prevent water hammer, drain coil before admitting steam.
3. Do not exceed one foot of lift between trap discharge and
return main for each pound of pressure differential.
4. Do not use this arrangement for units handling outside air.
Fig. 30 — Condensate Lift to Overhead Return
Refrigerant Piping, Direct-Expansion (DX)
Coils (Fig. 31) —
2 or 4 splits depending upon the unit size and coil circuiting.
See Table 9 for coil circuiting data. Each split requires its own
distributor nozzle, expansion valve, and suction piping. Suction
connections are on the air entering side when the coil is proper-
ly installed. Matching distributor connections for each coil split
are on the air leaving side. See unit label or certified drawing to
assure connection to matching suction and liquid connections.
27
See Table 10 for distributor part numbers.
Direct-expansion coils are shipped pressurized with dry air.
Release pressure from each coil split through valves in pro-
tective caps before removing caps.
Do not leave piping open to the atmosphere unnecessarily.
Water and water vapor are detrimental to the refrigerant
system. Until the piping is complete, recap the system and
charge with nitrogen at the end of each workday. Clean all
piping connections before soldering joints.
The lower split of face split coils should be first on, last off.
Row split coils utilize special intertwined circuits (as
shown in Fig. 31); either split of these row split coils can be
first on, last off.
24
Direct-expansion coils are divided into
CAUTION
Fig. 31 — Typical Direct-Expansion
Row Split Coil
Advertisement
Table of Contents
