Piping - Daikin Enfinity VFC Installation And Maintenance Manual

Piping

1 .
All units should be connected to supply and return
piping in a two-pipe reverse return configuration. A
reverse return system is inherently self-balancing
and requires only trim balancing where multiple
quantities of units with different flow and pressure drop
characteristics exist in the same loop. Check for proper
water balance by measuring differential temperature
reading across the water connections. For proper
water flow, the differential temperature should be 12°F
to 14°F (5°C to 8°C) for units in cooling mode.
A direct return system may also work, but proper water
flow balancing is more difficult to achieve and maintain.
2 . The piping can be steel, copper or PVC.
Note: If using PVC (schedule-40) construction grade
pipe or better, use the manufacturers recom-
mended high temperature adhesive. With PVC
piping the appropriate number of hanger brackets
must be used to help prevent sagging.
3 . Supply and return runouts usually join the unit via short
lengths of high pressure flexible hose which are sound
attenuators for both unit operating noise and hydraulic
pumping noise. One end of the hose should have
a swivel fitting to facilitate removal for service. Hard
piping also can be brought directly to the unit. This
option is not recommended since no vibration or noise
attenuation can be accomplished. The hard piping
must have unions to facilitate unit removal. See Figure
8, Figure 9, and Figure 10 for typical piping details.
Figure 8: Typical Vertical Unit Piping
4 . Some flexible hose threaded fittings are supplied with
sealant compound. If not, apply Teflon tape for a tight seal.
5 . Supply and return shutoff valves are required at
each unit. The return valve is used for balancing and
should have a "memory stop" so that it can always
be closed off but can only be reopened to the proper
position for the flow required.
6 . Do not connect any unit to the supply and return piping
until the water system has been cleaned and flushed
completely. After the cleaning and flushing has taken
place, the initial connection should have all valves wide
open in preparation for water system flushing (see
"Cleaning & Flushing Water System" on page 8).
IM 930-6 • Enfinity Vertical Water Source Heat Pumps
7 . Condensate piping can be steel, copper or PVC.
Each unit includes a condensate connection.
8 . Units are internally trapped.
9 . Do not locate any point in the drain system above
the drain connection of any unit.
10 . Automatic flow controlled devices must not be
installed prior to system cleaning and flushing.
11 . A high point of the piping system must be vented.
12 . Check local code for the need for dielectric fittings.
Note: Do not over-torque fittings. The maximum torque
without damage to fittings is 30 foot pounds. If a
torque wrench is not available, use as a rule of
thumb, finger-tight plus one quarter turn.
Figure 9: Typical Vertical Installation and Unit Piping
1 Supply Air Ducting
2 Acoustical Thermal Lining (10 ft.)
3 Line Voltage - 7/8" (22 mm) Hole
4 Low Voltage - 7/8" (22 mm) Hole
5 Flexible Duct Collar
6 Louvered Door for Return Air
7 Condensate Drain Connection
8 Flexible Return Hose with Flow Controller/Ball Valve (3/4" FPT)
9 Flexible Supply Hose with Y-Strainer/Ball Valve (3/4" FPT)
10 Access Panel to Controller
11 LED Annunciator Status Lights
12 Vibration Isolation Pad
10
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