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37
START-UP
Use the procedure outlined below to initiate proper unit
start-up.
NOTE: This equipment is designed for indoor installation only.
Operating Limits
ENVIRONMENT — This equipment is designed for outdoor
installation ONLY. Extreme variations in temperature, humidi-
ty and corrosive water or air will adversely affect the unit per-
formance, reliability and service life.
POWER SUPPLY — A voltage variation of ± 10% of name-
plate utilization voltage is acceptable.
UNIT STARTING CONDITIONS — See Table 15 for unit
starting conditions.
Table 15 — Starting Conditions — 50RTP Units
LEGEND
NOTE: These starting conditions are not normal or continuous
operating conditions. It is assumed that such a start-up is for
the purpose of bringing the building space up to occupancy
temperature. See Table 16 for operating limits.
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. Room temperature
should be approximately 70 to 75 F dry bulb. Loop water
temperature entering the heat pumps should be between
60 and 110 F.
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. See Table 15.
Table 16 — Operating Limits — 50RTP Units
LEGEND
Scroll Compressor Rotation — It is important to be
certain compressor is rotating in the proper direction. To
determine whether or not compressor is rotating in the proper
direction, perform the following procedure.
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 an elevated level of 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. Check the elevation and
cleanliness of the condensate lines; any dripping could be
a sign of a blocked line. Be sure the condensate trap in-
cludes 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.
5. Air temperature drop across the coil should be checked
when compressor is operating. Air temperature drop
should be between 15 and 25 F.
Unit Start-Up Heating Mode
NOTE: Operate the unit in heating cycle after checking the
cooling cycle. Allow five minutes between tests for the pres-
sure 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
pressures.
5. Once the unit has begun to run, check for warm air deliv-
ery at the unit grille.
6. Air temperature rise across the coil should be checked
when compressor is operating. Air temperature rise
should be between 20 and 30 F after 15 minutes at load.
7. Check for vibration, noise and water leaks.
AIR LIMITS COOLING HEATING
Minimum Entering Air 40 F 40 F
Maximum Entering Air (db) 110 F 80 F
WATER LIMITS
Minimum Entering Fluid 40 F 20 F
Maximum Entering Fluid 120 F 90 F
db — Dry Bulb
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.
AIR LIMITS COOLING HEATING
Minimum Entering Air 60 F 50 F
Maximum Entering Air (db) 90 F 80 F
WATER LIMITS
Minimum Entering Fluid 40 F 20 F
Maximum Entering Fluid 120 F 90 F
db — Dry Bulb