Compressor Rotation; Refrigerant Charge; No Charge; Low Charge Cooling - Carrier 50ZH Series Installation, Start-Up And Service Instructions Manual

HIGH-VOLTAGE LOW-VOLTAGE
POWERWIRING WIRING ENTRY
ENTRY HOLE HOLE
Fig. 11--Unit Electrical Connection
COMPRESSOR
CONTACTOR
\
C00010
TRANSFORMER
0 o
0
o
0 (3,
ELECTRIC GROUND INDOOR OUTDOOR FAN MOTOR HIGH
HEATER LUG FAN AND COMPRESSOR VOLTAGE
FUSES RELAY START CAPACITOR LEADS
C00011
Fig. 12--Control Box Wiring
Step 2iStart-Up Cooling Section and Make Adjustments
W , W
Complete the required procedures given in the Pre-Start- Up
section this page belore starting the unit. Do not jumper any
sali:ty devices when operating the unit.
Do not operate the compressor in cooling mode when the
outdoor temperature is below 40 F.
Do not rapid-cycle the compressor. Allow 5 minntes between
"on" cycles to prevent compressor damage.
CHECKING COOLING CONTROL OPERATION
Start and check the unit (or proper cooling control operation as
follows:
10
1. Place room thermostat SYSTEM switch in OFF position.
Observe that blower motor starts when FAN switch is placed
in ON position and shuts down within 30 seecnnds when FAN
switch is placed in AUTO position.
2. Place SYSTEM switch in COOL position and FAN switch in
AUTO position. Set cooling control below room temperature.
Observe that compressor, outdoor fan, and indoor blower
motors start and that reversing valve shifts. Observe that
cooling cycle shuts down when control setting is satisfied.
Reversing valve (RV) remains energized.
3. Place system switch in HEAT position. Observe that compres-
sor, indoor fan and outdoor fan energize (Reversing Valve is
deenergized in heat pump heating mode). Set control above
room temperature. Observe that heating cycle shuts down
when control setting is satisfied.
4. When using an automatic changeover room thermostat, place
both SYSTEM and FAN switches in AUTO. positions.
Observe that unit operates in Cooling mode when temperature
control is set to "call li)r cooling" (below room temperature),
and unit operates in Heating mode when temperature control
is set to "call lot heating" (above room temperature).
COMPRESSOR ROTATION
On all 3 Phase units it is important to be ceriain compressor is
rotating in the proper direction. To determine whether or not
compressor is rotating in the proper direction:
1. Connect service ganges 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 and tag disconnect.
2. Reverse any two of the unit power leads.
3. Turn on power to the unit.
The suction and discharge pressure levels should now move to
their normal start-up levels.
NOTF:: When the compressor is rotation in the wrong direction,
the unit makes an elevated level of noise and does not provide
cooling.
Step a--Refrigerant Charge
Rel]'igerant Charge Amount of rel_'igerant charge is listed on
unit nameplate and in Table 1. Re{i:r to Carrier Rel?'igerant Service
Techniques Manual, Re{?'igerants section. Unit panels lnust be in
place when unit is operating during charging procedure. Unit nmst
operate a minimum of 15 minutes belk_re checking charge.
NO CHARGE
Re{i:r to Can'ier Refrigerant Service Techniques. Use standard
evacuating techniques. Alter evacuating system, weigh in the
specified amount of re{5"igerant (re{i:r to Table 1).
LOW CHARGE COOLING
Using cooling charging chart (see Fig. 18 22),Vary rel?'igerant
until conditions of the chart are met. Note that charging chart is
difli:rent {?'omthose normally used. Charts are based on charging
the units to the correct superheat {k)r the various operating
conditions. An accurate pressure gauge and temperature-sensing
device is required. Connect the pressure gauge to the service port
on the suction line. Connect temperature sensing device to the
suction line near the colnpressnr and insulate it so that outdoor
ambient temperature does not al_i_ct reading.