AAON RN-140 - Manual (Page 60)

60
unit can operate without damaging unit
components.
Table 18 - Standard Brazed Plate Heat
Exchanger Water Connections
Model (RN-)
Supply and Return
Connection Size
006, 007
1” NPT
008, 010, 009, 011,
013, 015, 016, 018,
020
1 1/2” NPT
025, 030 2” NPT
026, 031, 040 2 1/2” Grooved Pipe
050, 055, 060, 070
3” Grooved Pipe
065, 075, 090, 105
4” Grooved Pipe
120, 130, 140 5” Grooved Pipe
Table 19 - SMO 254 Brazed Plate Heat
Exchanger Water Connections
Model (RN-)
Supply and Return
Connection Size
016, 018, 020, 025,
030
1 1/2” NPT
Only use approved water pipe material.
Avoid using galvanized material for water
lines/fittings as the material is corrosive and
may cause fouling of the water system.
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 makeup 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
WATER PRESSURE
Prior to connection of condensing
water supply, verify water pressure is
less than maximum pressure shown
on unit nameplate. To prevent injury
or death due to instantaneous
release of high pressure water, relief
valves should be field supplied on
water
piping. Supply water
connection may require a backflow
preventer to prevent supply makeup
water from backing up into the public
water system.
WARNING
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