Magic Aire HCA 04, Инструкция по установке, эксплуатации и обслуживанию

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035-000049-001 Page 17 HCA IOM 1.1 8-28-2017
stalled level to maintain the inherent slope.
Also ensure the unit is installed high enough
to allow the piping to be installed correctly,
especially the traps which require long drip
legs.
11. Do not fail to provide all coils with the proper
air vents to eliminate noncondensable gas-
ses.
12. Do not support steam piping from the coil
units. Both mains and coil sections should
be supported separately.
IDT Steam Coil Installation — Refer to drawings
to position the coils properly with regard to the
location of the supply and return connections.
Ensure that the IDT coil is pitched with the tubes
draining toward the header. The AHUs provide
proper coil pitch when the AHU is installed level.
Refer to schematic piping diagrams and piping
connection notes for the recommended piping
methods.
Refrigerant Piping, Direct-Expansion (DX)
Coils —
Direct-expansion coils are divided into 1 or 2 splits
depending upon the unit size and coil circuiting.
Each split requires its own distributor nozzle, ex-
pansion valve, and suction piping. Suction con-
nections are on the air entering side when the coil
is properly installed. Matching distributor connec-
tions for each coil split are on the air leaving side.
See unit label or certified drawing to assure con-
nection to matching suction and liquid connec-
tions.
The lower split of face split coils should be
first on,
last off (Fig. 13).
Row split coils utilize special intertwined circuits;
either split of these row split coils can be
first on,
last off .
SUCTION PIPING — Connect suction piping as shown
in Fig. 13 for face split coil.
Fig. 13 — Face Split Coil Suction Line Piping
(TXV — Thermostatic Expansion Valve)
Suction line from coil connection to end of the 15-
diameter-long riser should be same tube size as coil
connection to ensure proper refrigerant velocity.
Size remaining suction line to compressor for a
pressure drop equivalent to 2.0 F. This will provide a
total suction line header pressure drop equivalent to
approximately 2.5 F. Refer to Fig. 14 for piping risers
to the compressor.
To minimize the possibility of flooded starts and com-
pressor damage during prolonged light load operation,
install an accumulator in the suction line or a solenoid
in the liquid line of last-on, first off split in row-split ap-
plications.
Fig. 14 — Suction Line Riser Piping
CAUTION
Direct-expansion coils are shipped pressurized
with dry nitrogen. Release pressure from each
coil split through valves in protective caps before
removing caps.
Do not leave piping open to the atmosphere un-
necessarily. Water and water vapor are detri-
mental 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.
Failure to follow these procedures could result in
personal injury or equipment damage.