AAON RQ-006 - Manual (Page 48)

48
Condenser water pump must be field sized
and
installed between the cooling
tower/geothermal loop and self-contained
unit. System should be sized in accordance
with
the ASHRAE Handbook. Use
engineering guidelines to maintain equal
distances for supply and return piping and
limit bend radiuses to maintain balance in
the system. Balancing valves, permanent
thermometers and gauges may be required.
Before connection to the unit the condenser
water 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 tube damage.
Mineral content of the condenser water must
be controlled. All make-up water has
minerals in it and as the water is evaporated
in the cooling tower, these minerals remain.
As the mineral content of the water
increases, the conductivity of the water
increases.
Field provided and installed water treatment
program must be compatible with stainless
steel, copper, aluminum, ABS plastic, and
PVC. Batch feed processes should never be
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.
WATER PIPING
Follow national and local codes when
installing water piping. Connections
to
the unit should incorporate
vibration eliminators to reduce noise
and vibration and shutoff valves to
facilitate servicing. Supply and return
water piping must be at least as large
as the unit connections and larger
depending on length of runs, rise and
bends.
CAUTION
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