010-200002-000
Page 24
HB IOM 1.1 2-13-2014
NOTES (Figure 28):
1.
A bypass is necessary around trap and valves
when uninterrupted operation is necessary.
2.
Bypass to be the same size as trap orifice but nev-
er less than 1/2 inch.
NOTES:
1.
Flange or union is located to facilitate coil re-
moval.
2.
When a bypass with control is required.
3.
Flash trap can be used if pressure differential
between supply and condensate return exceeds
5 psi.
4.
Coils with different pressure drops require indi-
vidual traps. This is often caused by varying air
velocities across the coil bank.
5.
Dirt leg may be replaced with a strainer. If so,
tee on drop can be replaced by a reducing ell.
6.
The petcock is not necessary with a bucket trap
or any trap which has provision for passing air.
The great majority of high pressure return mains
terminate in hot wells or deaerators which vent
the air.
Fig. 29 — Multiple Coil High Pressure Piping
NOTES:
1.
Flange or union is located to facilitate coil re-
moval.
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 in-
dividual traps. This is often caused by varying
air velocities across the coil bank.
Fig. 30 — Multiple Coil Low Pressure
Piping Gravity Return
NOTES:
1. Flange or union is located to facilitate coil removal.
2. To avoid 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. 31 — Multiple Coil Low Pressure Piping
Gravity Return
