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16
Step 6 — Condensate Drain
HORIZONTAL UNITS (50RHC,RHR,RHS) — Slope the
unit toward the drain at a
1
/
4
in. drop at drain end. See Fig. 15.
If it is not possible to meet the required pitch, install a conden-
sate pump at the unit to pump condensate to building drain.
Horizontal units are not internally trapped, therefore an ex-
ternal trap is necessary. Install each unit with its own individual
trap and means to flush or blowout the condensate drain line.
Do not install units with a common trap or vent. For typical
condensate connections see Fig. 16.
NOTE: Never use a pipe size smaller than the connection.
VERTICAL UNITS (50RVC,RVR,RVS) — Each unit uses a
condensate hose inside all cabinets as a trapping loop, therefore
an external trap is not necessary. See Fig. 17.
Each unit must be installed with its own individual vent and
means to flush or blowout the condensate drain line. Do not in-
stall units with a common trap or vent.
VENTING — Install a vent in the condensate line of any
application that may allow dirt or air to collect in the line. Con-
sider the following:
• Always install a vent where an application requires a
long horizontal run.
• Always install a vent where large units are working
against higher external static pressure and to allow
proper drainage for multiple units connected to the same
condensate main.
• Be sure to support the line where anticipated sagging from
the condensate or when “double trapping” may occur.
• If condensate pump is present on unit, be sure drain con-
nections have a check valve to prevent back flow of con-
densate into other units.
Step 7 — Piping Connections — Depending on the
application, there are 3 types of WSHP piping systems to
choose from: water loop, ground-water and ground loop. Refer
to Piping Section of Carrier System Design Manual for addi-
tional information.
All WSHP units use low temperature soldered female pipe
thread fittings for water connections to prevent annealing and
out-of-round leak problems which are typically associated with
high temperature brazed connections. Refer to Tables 1-3 for
connection sizes. When making piping connections, consider
the following:
• Use a backup wrench when making screw connections to
unit to prevent internal damage to piping.
• Insulation may be required on piping to avoid condensa-
tion in the case where fluid in loop piping operates at
temperatures below dew point of adjacent air.
• Piping systems that contain steel pipes or fittings may
be subject to galvanic corrosion. Dielectric fittings may
be used to isolate the steel parts of the system to avoid
galvanic corrosion.
WATER LOOP APPLICATIONS — Water loop applications
usually include a number of units plumbed to a common pip-
ing system. Maintenance to any of these units can introduce air
into the piping system. Therefore, air elimination equipment
comprises a major portion of the mechanical room plumbing.
The flow rate is usually set between 2.25 and 3 gpm per ton
of cooling capacity. For proper maintenance and servicing,
pressure-temperature (P/T) ports are necessary for temperature
and flow verification.
In addition to complying with any applicable codes, consid-
er the following for system piping:
• Piping systems using water temperatures below 50 F
require
1
/
2
-in. closed cell insulation on all piping surfaces
to eliminate condensation.
• Avoid all plastic to metal threaded fittings due to the
potential to leak. Use a flange fitted substitute.
• Teflon tape thread sealant is recommended to minimize
internal fouling of the heat exchanger.
• Use backup wrench. Do not overtighten connections.
• Route piping to avoid service access areas to unit.
• Flush the piping system prior to operation to remove dirt
and foreign materials from the system.
GROUND-WATER APPLICATIONS (Not Applicable to
50RHC,RVC Units) — Typical ground-water piping is
shown in Fig. 18. In addition to complying with any appli-
cable codes, consider the following for system piping:
• Install shut-off valves for servicing.
• Install pressure-temperature plugs to measure flow and
temperature.
• Connect boiler drains and other valves using a “T” con-
nector to allow acid flushing for the heat exchanger.
• Do not overtighten connections.
• Route piping to avoid service access areas to unit.
• Use PVC SCH80 or copper piping material.
NOTE: PVC SCH40 should not be used due to system high
pressure and temperature extremes.
Fig. 15 — Horizontal Unit Pitch
NOTE: Trap should be deep enough to offset maximum unit static
difference. A 4-in. trap is recommended.
Fig. 16 — Trap Condensate Drain
Alternate
Condensate
Location
Vent
1/4” per foot
slope to drain
3/4” Copper FPT/PVC
Water
Connections
1/2”
1/2”
3/4” PVC
NOTE: Unit does not need to be sloped toward drain.
Fig. 17 — Vertical Condensate Connection
1/4” Pitch for
Drainage
Drain Connection
Pitch Toward
Drain