AAON RN-140 - Manual (Page 61)

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used as concentrated chemicals can cause
corrosion. Never use hydrochloric acid
(muriatic acid) or chlorine as it will corrode
stainless steel.
NOTE: Ball valves should be installed in
the condenser water supply and return lines
for unit isolation and water flow balancing.
All manual flow valves should be of the ball
valve design. Globe or gate valves should
not be used due to high pressure drops and
poor throttling characteristics.
Pressure
and temperature ports are
recommended in condenser water supply
and return lines for system balancing. These
openings should be 5 to 10 pipe diameters
from the unit water connections. To allow
for mixing and temperature stabilization,
wells in the water piping should extend at
least ½ pipe diameter into the pipe.
Piping systems should not exceed 10 ft/sec
fluid velocity to ensure tube wall integrity
and reduce noise.
Condensate Drain Piping
6-25 and 30 ton units are equipped with one
condensate drain pan connection, on the
right side of the unit, and are furnished with
a p-trap for field installation. 26 and 31-140
ton units are equipped with two condensate
drain connections, one on the left side of the
unit and one on the right side of the unit, and
are furnished with two p-traps for field
installation.
All drain connections must be used and
individually trapped to ensure a minimum
amount of condensate accumulation in the
drain pans. ABS type cement should be used
to join the drain pipe connections.
Drainage of condensate directly onto the
roof may be acceptable in certain areas, refer
to local codes. If condensate is to drain
directly onto the roof a small drip pad
should be placed below the drain to protect
the roof from possible damage.
If condensate is piped into the building
drainage system, the drain pipe should
Each heat exchanger is equipped
with a refrigerant pressure relief
device to relieve pressure should
excessive
condensing pressures
(>675 psig) occur. Codes may
require
installing contractor to
connect and route relief piping
outdoors. The relief valve
has a 5/8”
male flare outlet connection.
CAUTION
Installing contractor is responsible for
properly sizing and installing water
system components. Improper fluid
flow due to valves, piping, or
improper pump operation may result
in unacceptable unit operation and
void warranty.
CAUTION
PVC (Polyvinyl Chloride) and CPVC
(Chlorinated Polyvinyl Chloride) are
vulnerable to attack by certain
chemicals. Polyolester (POE) oils
used
with R-410A and other
refrigerants, even in trace amounts,
in a PVC or CPVC piping system will
result in stress cracking of the piping
and fittings and complete piping
system failure.
CAUTION