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START-UP
Use the procedure outlined below to initiate proper unit
start-up.
NOTE: This equipment is designed for indoor installation
only. Set the thermostat to the highest setting.
Operating Limits
ENVIRONMENT — This equipment is designed for indoor
installation only. Extreme variations in temperature, humidity
and corrosive water or air will adversely affect the unit perfor-
mance, reliability and service life.
POWER SUPPLY — A voltage variation of ± 10% of name-
plate utilization voltage is acceptable.
UNIT STARTING CONDITIONS — Units start and operate
in an ambient temperature of 45 F with entering-air tempera-
ture at 50 F, entering-water temperature at 60 F and with both
air and water at the flow rates used.
NOTE: These operating limits are not normal or continuous
operating conditions. Assume that such a start-up is for the
purpose of bringing the building space up to occupancy tem-
perature. See Table 9 for operating limits.
WARNING
When the disconnect switch is closed, high voltage is pres-
ent in some areas of the electrical panel. Exercise caution
when working with the energized equipment. Failure to
heed this warning may result in personal injury.
1. Restore power to system.
2. Turn thermostat fan position to ON. Blower should start.
3. Balance airflow at registers.
4. Adjust all valves to the full open position and turn on the
line power to all heat pump units.
5. Operate unit in the cooling cycle. Refer to Table 9 for unit
operating limits.
NOTE: Three factors determine the operating limits of a unit:
(1) entering air temperature, (2) water temperature and (3)
ambient temperature. Whenever any of these factors are at a
minimum or maximum level, the other two factors must be at a
normal level to ensure proper unit operation.
Table 9 — Operating Limits
AIR LIMITS
COOLING
Minimum Ambient Air Temperature F
Maximum Ambient Air Temperature F
Minimum Evaporator Entering Air db/wb F
Rated Air Coil Entering Air db/wb F
Maximum Evaporator Entering Air db/wb F
Minimum Water Coil Entering Fluid
Temperature F
Water Loop Typical Coil Entering Fluid
Range Temperature F
Maximum Water Coil Entering Fluid
Temperature F
HEATING
Minimum Ambient Air Temperature F
Maximum Ambient Air Temperature F
Minimum Evaporator Entering Air db F
Rated Air Coil Entering Air F
Maximum Evaporator Entering Air db F
Normal Water Coil Entering Fluid Range F
Minimum Water Coil Entering Fluid F
LEGEND
db — Dry Bulb
wb — Wet Bulb
*Antifreeze solution is required at these fluid temperatures.
EXTENDED
STANDARD
RANGE
UNIT
OPTION
50
50
100
100
68/57
68/57
80/67
80/67
95/85
98/85
50
50
70/90
70/90
110
110
50
40
100
85
50
50
68
68
80
80
50-80
25-80*
50
20*
26
Scroll Compressor Rotation —
certain the compressor is rotating in the proper direction. To
determine whether or not the compressor is rotating in the
proper direction:
1. Connect service gages to suction and discharge pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge
pressure should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge
pressure does not rise to normal levels:
1. Turn off power to the unit. Install disconnect tag.
2. Reverse any two of the unit power leads.
3. Reapply power to the unit and verify pressures are correct.
The suction and discharge pressure levels should now move
to their normal start-up levels.
When the compressor is rotating in the wrong direction, the
unit makes more noise and does not provide cooling.
After a few minutes of reverse operation, the scroll com-
pressor internal overload protection will open, thus activating
the unit lockout. This requires a manual reset. To reset, turn the
thermostat on and then off.
NOTE: There is a 5-minute time delay before the compressor
will start.
Unit Start-Up Cooling Mode
1. Adjust the unit thermostat to the warmest position.
Slowly reduce the thermostat position until the compres-
sor activates.
2. Check for cool air delivery at unit grille a few minutes
after the unit has begun to operate.
3. Verify that the compressor is on and that the water flow
rate is correct by measuring pressure drop through the
heat exchanger using P/T plugs. See Table 10. Check the
elevation and cleanliness of the condensate lines; any
dripping could be a sign of a blocked line. Be sure the
condensate trap includes a water seal.
4. Check the temperature of both supply and discharge
water. If temperature is within range, proceed. If tempera-
ture is outside the range, check the cooling refrigerant
pressures. Contact Carrier Commercial Services or prod-
uct management for acceptable temperature ranges.
5. Check air temperature drop across the coil when com-
pressor is operating. Air temperature drop should be
between 15 and 25 F.
Table 10 — Water Temperature Change
through Heat Exchanger
WATER FLOW RATE (GPM)
For Closed Loop: Ground Source or
Cooling/Boiler Systems at 3 gpm/ton
For Open Loop: Ground Water Systems at
1.5 gpm/ton
Unit Start-Up Heating Mode
NOTE: Operate the unit in heating cycle after checking the
cooling cycle. Allow 5 minutes between tests for the pressure
or reversing valve to equalize.
1. Turn thermostat to lowest setting and set thermostat
switch to HEAT position.
2. Slowly turn the thermostat to a higher temperature until
the compressor activates.
3. Check for warm air delivery at the unit grille within a few
minutes after the unit has begun to operate.
4. Check the temperature of both supply and discharge
water. If temperature is within range, proceed. If tempera-
ture is outside the range, check the heating refrigerant
It is important to be
COOLING
HEATING
RISE (F)
DROP (F)
Min
Max
Min
Max
9
12
4
8
20
26
10
17
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