Magic Aire HHA Series, Инструкция по установке, эксплуатации и обслуживанию

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035-000029-001 Page 27 HHA IOM 1.4 10/11/2021
NOTE: Piping should be installed by a qualified
installer familiar with the type of piping to be in-
stalled. Perform piping to industry best practices.
STEAM COILS — Position the steam supply con-
nection at the top of the coil, and the return
(condensate) connection at the bottom.
Figure 7 illustrates the normal piping compo-
nents and the suggested locations for high, medi-
um, or low-pressure steam coils. The low-pressure
application (zero to 15 psig) can dispense with the
¼-in. petcock for continuous venting located above
the vacuum breaker (check valve).
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 pre-
heat outside air, install 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.
NOTE: DO NOT use an immersion thermostat to
override a duct thermostat and open the steam sup-
ply valve. For vacuum return systems, the vacuum
breaking check valve would be piped into the con-
densate line between the trap and the gate valve
instead of open to the atmosphere.
Figure 8 illustrates the typical piping at the end of
every steam supply main. Omitting this causes
many field problems and failed coils.
Figure 9 shows the typical field piping of multiple
coils. Use this only if the coils are the same size
and have the same pressure drop. If this is not the
case, an individual trap must be provided for each
coil.
Figure 10 shows a multiple coil arrangement ap-
plied to a gravity return, including the open air relief
to the atmosphere, which DOES NOT replace the
vacuum breakers.
Figure 11 illustrates the basic condensate lift piping.
NOTES:
1.
Flange or union is located to facilitate coil
removal.
2. Flash trap may be used if pressure differen-
tial between steam and condensate return
exceeds 5 psi.
3. Dirt leg may be replaced with a strainer. If
so, tee on drop can be replaced by a reduc-
ing ell.
4. The petcock is not necessary with a bucket
trap or any trap which has provision for
passing air. The great majority of high or
medium pressure returns end in hot wells or
deaerators which vent the air.
Fig. 7 — Low, Medium or High
Pressure Coil Piping
Steam Coil Piping Recommendations
GENERAL — Use straps around the coil casing to
lift and place the coil.
NOTES (Figure 8):
1.
A bypass is necessary around trap and
valves when uninterrupted operation is nec-
essary.
2. Bypass to be the same size as trap orifice
but never less than 1/2 inch.
Fig. 8 — End of Steam Supply
Main Piping Detail
INSTALLATION-Piping (cont’d)