Installation manual

035-19084-001-D-0504
50 Unitary Products Group
PHASING
Check for proper compressor rotation. If the blower or
compressors rotate in the wrong direction at start-up,
the electrical connection to the unit is misphased.
Change the incoming line connection phasing to obtain
proper rotation. (Scroll compressors operate in only
one direction. If the scroll is drawing low amperage,
has similar suction and discharge pressures, or pro-
ducing a high noise level, the scroll is misphased).
CHECKING SUPPLY AIR CFM
The RPM of the supply air blower will depend on the
required CFM, the unit accessories or options and the
static resistances of both the supply and the return air
duct systems. With this information, the RPM for the
supply air blower and the motor pulley adjustment
(turns open) can be determined from the Blower Per-
formance Data Tables.
FIGURE 15 - CHARGING CHART - 25 TON
DR300 Charging Chart
150
170
190
210
230
250
270
290
310
330
350
55 60 65 70 75 80 85
Suction pressure (psi)
Discharge pressure (psi)
115º
105º
95º
85º
75º
65º
Both fans must be running when charging the unit. One fan may switch off at low ambient temperatures making this chart inaccurate.
Outdoor Temp (ºF)
Scroll compressors require proper rotation to
operate correctly. Do not change the internal
wiring to make the blower, condenser fans, or
compressor rotate correctly. Change the
incoming power to the main terminal block to
obtain proper rotation.
FIGURE 16 - BELT ADJUSTMENT