AAON CL-230 - Manual (Page 18)

18
EVAPORATIVE-COOLED
CONDENSER cont.
4. Turn rotating element by hand to assure that it
rotates freely.
Running:
Periodically inspect pump while running, but
especially after initial start-up and after repairs.
1. Check pump and piping for leaks. Repair
immediately.
2. Record pressure gauge readings for future
reference.
3. Record voltage, amperage per phase, and kW.
Condenser Fan Motors:
• The direct-drive condenser motors on AAON
evaporative-cooled condensers are 1200-rpm
premium efficiency motors controlled by a VFD.
These motors are totally enclosed air over motors
with weep holes in the bottom end bell so that
any condensation can drain out of the motor.
• The motors have a small electric resistance
heater installed inside the casing to keep the
motors warm when they are deactivated. The
heaters are designed to keep the interior of the
motor 10°F warmer than the surrounding
ambient temperature. This prevents condensation
from forming inside the motor.
• Ensure that fan is tightly mounted to the motor
shaft and the motor mounting bolts are aligned
and secure.
Water Make-up Valve:
• The sump water level is controlled by a set of
conductivity probes at different levels in the
sump. This water level controller is located in
the vestibule behind the condenser pump. There
are four conductivity probes in this controller.
There is a reference probe (shown as “ref” on the
wiring diagram). This probe is one of the two
longest probes. The other long probe is the low
water level probe (shown as “lo” on the wiring
diagram). The medium length probe is for the
medium water level (shown as “med” on the
wiring diagram). The short probe is for the high
water level (shown as “hi” on the wiring
diagram). There is a solenoid valve in the make-
up water line that is activated by the water level
controller. The water level controller determines
the level of water in the sump based on
conductivity between two probes. If the
controller sees conductivity between two probes,
it knows that water is at least at the level of that
probe.
• If the water in the sump is below the low probe,
it will not allow the condenser pump or the sump
heater to operate. It will activate the make-up
water solenoid to try to fill the sump assuming
water is flowing to the unit. Once water is above
the low probe, it will allow the condenser pump
and sump heater (if ordered and the ambient
temperature is below 40°F) to operate. The
make-up water solenoid will remain activated
until water gets to the high water level. The
make-up water solenoid will deactivate until
water gets to the medium water level. In normal
operation, the water level should swing between
the medium and high water levels. The
maximum high water level should be 1” below
the overflow drain which occurs after the make-
up water valve shuts off when the water level
reaches the high level probe.
• Make-up water supply pressure should be
maintained between 15 and 60 psig for proper
operation of the valve. The make-up water valve
assembly should be inspected monthly and
adjusted as required. Replace the valve seat if
leakage occurs when the valve is in the closed
position.