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Use the procedure outlined below to initiate proper unit start-up:
When the disconnect switch is closed, high voltage is
present in some areas of the electrical panel. Exercise
caution when working with energized equipment.
1.
Turn all valves to their full open position. Turn on
the line power to all heat pump units.
NOTE: The units with scroll compressors are
tested for matched rotation of fan motor and
scroll compressors. At startup check fan
rotation, if fan rotation is correct all scroll
compressor will automatically have correct
rotation. If fan rotation is incorrect, interchange
any two power supply lead connections at
the disconnect. Scroll compressors with
INCORRECT rotation show following operating
characteristics: 1) High sound level 2)High
suction pressure 3) Low current draw.
2.
Operate each unit in the cooling cycle. Room
temperature should be approximately 70
°
to 75
°
F
DB, and 61
°
to 65
°
F WB. Loop water temperature
entering the heat pumps should be between 70
°
F
and 110
°
F.
When the unit is operating in the cooling mode
under ARI conditions, the leaving water temperature
is approximately 10
°
F warmer than the entering
water temperature at 3 GPM / ton.
a.
Turn the unit thermostat to the cooling position.
If the unit has an optional MCO thermostat, set
the selector switch to COOL. Both the fan and
compressor should run.
For heat pumps with ACO, adjust the cooling
set point to a temperature at least 3
°
F below
room temperature.
b.
Check for cool air delivery at the system grille
within a few minutes after the unit has begun to
operate. List the identification number of any
machines that do not function.
c.
Check the elevation and cleanliness of the
condensate lines. Dripping may be a sign of a
blocked line.
3.
Operate each heat pump in the heating cycle imme-
diately after checking cooling cycle operation. A
time delay will prevent the compressor from re-
starting for approximately 5 minutes.
NOTE: Large Commercial heat pump units are
UNIT START-UP
WARNING
designed to start heating at a minimum return air
temperature of 40
°
F with normal water flow rate
and ambient temperature.
a.
If the unit has an optional MCO thermostat, set
the temperature indicator to the highest setting
and set the selector switch to HEAT. The fan
and the compressor should start.
If the unit has an optional ACO thermostat, set
the temperature indicator to the far right setting
and set the selector switch to AUTO. The fan
and the compressor should start.
b.
Once the unit has begun to run, check for warm
air delivery at the unit grille. List the serial
number of any machines that do not function.
4.
Establish a permanent operating record by logging
the unit operating conditions at initial start-up for
each unit.
5.
If a unit fails to operate, conduct the following
checks:
a.
Check the power supply. It should comply with
the electrical specifications described on the unit
nameplate.
b.
Look for wiring errors. Check for loose terminal
screws where wire connections have been made
on both the line and low-voltage terminal
boards.
c.
Check for dirty filters. A clogged filter will
cause safety cutouts to stop unit operation.
d.
Check the supply and return piping. They must
be properly connected to the inlet and outlet
connections on the unit.
e.
Check the fan. If the fan fails to operate, verify
that the fan wheel turns freely and that it is
secured to the shaft. Also verify that the fan
operates in both heating and cooling modes,and
rotates in the proper direction.
f.
If the checks described above fail to reveal the
problem and the unit still will not operate,
contact a trained service technician to ensure
proper diagnosis and repair of the equipment.
NOTE: Refer to Controller AOM provided
with the unit for status light operation and
fault codes
