Heating Mode Charge; High-Pressure Relief Valve; Loss Of Charge Switch; Compressor Overload - Carrier 50ZH Series Installation, Start-Up And Service Instructions Manual

GROUND
r LEAD
/ SINGLE'PHASE I_- =--
3-PHASE / CONNECTIONS 4-
CONNECTIONS 1TO DISCONNECTI .
TO DISCONNECT1PER NEC L_ - - -
PER NEC | L
L
UNIT GROUND
_ Z__ BLK- -/
z__ YEL- -/
- z_- BLU- -/
Fig. 13--Line Power Connections
C00012
©
®
®
®
THERMOSTAT
AND SUBBASE
L..__
[_
L_.__.
_BRN--
-_ ORN --
_RED --
"_ GRN --
UNIT CONTROL POWER
SPLICE BOX
Fig. 14--Control Connections
C99056
TO USE THE COOLING CHARGING CHART
This metllod is to be used in cooling mode only. Take tile outdoor
ambient temperature and read the suction pressure gauge. Reli:r to
charts to determine what the suction temperature should be. If
suction temperature is high, add rcl_'igerant. If suction temperature
is low, carefldly recover some of the charge. Recheck the suction
pressure as charge is adjusted.
Example: (See Fig. 18)
Outdoor Temperature 85°F
Suction Pressure--74 psig
Suction Temperature should be--60°F
Note--Suction Temperature may vary +/- 5°F.
HEATING MODE CHARGE
Do not attempt to adjust charge by cooling methods while in heat
pump heating mode. Recover refrigerant and weigh in according to
unit data plate relhigerant data.
Step 4--Indoor Airflow and Airflow Adjustments
NOTE: For cooling operation, the recommended airflow is 350 to
450 cfln per each 12,000 Bmh of rated cooling capacity.
Table 4 shows dry coil air delivery liar horizontal discharge units.
Tables 5-7 show pressure drops.
NOTE: Be sure that all supply- and return-air grilles are open,
free fi'om obstructions, and adjusted properly.
Disconnecl elech'ical power to the unil and inslall lockonl lag
before changing blower speed. Electrical shock can cause
serious injury or dealh.
To change the speed of the indoor Ian motor (IFM), remove the fan
motor speed leg lead fi'om the indoor fan relay (IFR) with units
030, 042, 048 & 060 or the time delay relay (TDR) on 036 size and
replace with lead lor desired blower motor speed, lnsuh_te the
removed lead to al,oM col/act l_ith chassis parts.
FOR 460-V MOTORS
The motor leads are color coded as lbllows:
3-SPEED (060 ONLY) 2-SPEED
black = high speed black = to purple
yellow = line
orange = medium speed purple = to black
blue = low speed red = line
To change the speed of the indoor tim motor (1FM) from low speed
to high speed, remove the red lead from the indoor-fan relay (IFR).
ON 2 Speed Motors: Insulate the red lead to avoid contact with
any chassis parts. Separate the black lead fi'om the purple lead.
Connect the black lead to the IFR. Insulate the purple lead to avoid
contact with any chassis parts. ON 3-Speed Motors: remove the
fan motor speed leg lead freln the indoor (indoor) fan relay (1FR)
and replace with lead liar desired blower motor speed.
Step 5--Unit Controls
All compressors have die Ibllowing internal-protection controls.
HIGH-PRESSURE RELIEF VALVE
This valve opens when the pressure differential between the low
and high side becomes excessive.
Airflow can be changed by changing the lead connections of the
blower motor.
Units 50ZH 036, 048, and 060 blower motors are factory wired li)r
low speed operation. Units 50ZH030 and 042 are factory wired li)r
medium speed operation.
LOSS OF CHARGE SWITCH
Located on the outdoor liquid line is a low-pressure switch which
functions as a loss-of-charge switch. This switch contains a
Schrader core depressor. This switch opens at 7 psig and closes at
22 psig. No adjusm_ent is necessary.
FOR 208/230-V
The motor leads are color-coded as lk_llows:
3-SPEED 2-SPEED
black = high speed black = high speed
blue = medium speed
red = low speed red = low speed
COMPRESSOR OVERLOAD
This overload interrupts power to the compressor when either the
current or internal temperature become excessive, and automati-
cally resets when the internal temperature drops to a sale level.
This overload may require up to 60 minutes (or longer) to reset;
therelore, if the internal overload is suspected of being open,
disconnect the electrical power to the unit and check the circuit
througla the overload with an ohnnneter or continuity tester.
II