8
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 Table 1 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
should 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 0.040 and 0.054 l/s per
kW 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 10 C
require 12.7 mm 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 — Typical ground-
water piping is shown in Fig. 8. In addition to complying
with any applicable codes, consider the following for sys-
tem 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.
Pressure-
Temperature
Plugs
Boiler
Drains
Strainer – Field-InstalledAccessory
(16 to 20 mesh recommended for
filter sediment)
Shut-Off
Valve
Water
Control
Valve
Flow
Regulator
Pressure
Tank
Water Out
Water In
From Pump
Fig. 8 — Typical Ground-Water Piping Installation
