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Step 4 — Make Piping Connections
CONDENSER WATER PIPING (Water-Cooled Only) —
Always follow national and local codes when installing water
piping to ensure a safe and proper installation. Connections to
the unit should incorporate vibration eliminators to reduce
noise and vibration to the building, and shutoff valves to facili-
tate servicing.
Prior to connecting the unit(s) to the condenser water
system, the system should be flushed to remove foreign
material that could cause condenser fouling. Install a screen
strainer with a minimum of 20 mesh ahead of the condenser
inlet to prevent condenser fouling and internal condenser tube
damage from foreign material.
Supply and return water piping must be at least as large as
the unit connections, and larger for long runs. Refer to the
System Design Manual, Part 3, and standard piping practice,
when sizing, planning, and routing water piping. See dimen-
sion drawings (Fig. 2-14) for water connection sizes and
locations.
Units are furnished standard with a copper heat exchanger.
A cupronickel heat exchanger is also available as a
factory-installed option. Copper is adequate for closed loop
systems where good quality water is available. In conditions
where scale formation or water treatment is questionable, the
optional cupronickel heat exchanger should be used. Where the
water is especially corrosive or could lead to excessive fouling,
intermediate plate frame heat exchangers are recommended.
The unit is capable of operating with entering water temper-
atures as low as 50 F, without the need for head pressure
control. If the entering water temperature is expected to be
lower, or more stable unit operation is desired, a field-supplied
water-regulating valve may be used.
This unit has multiple independent refrigerant circuits with
separate condensers. The individual condensers are manifolded
together on the waterside to provide easy, single-point water
connections. In order to achieve proper head pressure control
when a water-regulating valve is used, a temperature-actuated
valve is recommended. This allows any of the independent
refrigerant circuits to operate while still modulating condenser
water flow in response to loop water temperature.
A glycol solution should be used if ambient temperatures
are expected to fall below freezing or if the loop water temper-
ature is below 50 F while operating in the reverse cycle heating
mode (heat pump units only). Refer to Table 4, which
lists freezing points of glycol at different concentrations. A
minimum concentration of 20% is recommended. Water
pressure drop will increase and unit performance will decrease
with increasing glycol concentrations.
Units with factory-installed waterside economizers have
cooling water passing through the economizer and condenser
in series while operating in the economizer mode. During
normal operation, water bypasses the economizer coil.
Table 4 — Glycol Freezing Points
All manual flow valves used in the system should be of the
ball valve design. Globe or gate valves must not be used due to
high pressure drops and poor throttling characteristics.
Do not exceed recommended condenser fluid flow rates
shown in Tables 5A and 5B. Serious damage or erosion of the
heat exchanger tubes could occur. Piping systems should not
exceed 10 fps fluid velocities to ensure quietness and tube wall
integrity. Refer to Tables 5A and 5B for condenser water pres-
sure drop versus flow rate. Flow rates outside of the published
range should not be used.
Ball valves should be installed in the supply and return lines
for unit isolation and water flow balancing.
CAUTION
Galvanized pipe or fittings are not recommended with
50BV units due to the possibility of galvanic corrosion
caused by dissimilar metals. When selecting piping
materials, use only approved piping materials that meet
applicable codes and that will handle the temperatures and
pressures that may be experienced in the application.
Piping systems will sweat if low temperature fluid is used
in the system. For these applications, supply and return
water piping should be insulated to protect from condensa-
tion damage. The minimum recommended entering water
temperature to the unit is 50 F.
% GLYCOL
FREEZE POINT (° F)
Ethylene Glycol Proplylene Glycol
20 18 19
30 79
40 –7 –5
50 –28 –27
Fig. 19 — DHS Limit Switch (P/N 190060)
a50-7268tf
Fig. 18 — DHS Pressure Limit Location
a50-8253