Step 5 - Install Condensate Drain Line; Step 6 - Complete Electrical Connections; General; Unbalanced 3-Phase Supply Voltage - Carrier Omnizone 50XCA06 Installation, Start-Up And Service Instructions Manual

Step 5 — Install Condensate Drain Line
The 50XCA unit has a drain connection for evaporator conden-
sate. When connecting condensate drains from the unit to floor
drains, sinks, or hoppers, connect drains downstream of trap to en-
sure that condensate does not drain back into the unit.
IMPORTANT: NEVER use pipe smaller than
in the drain run.
Pitch drain pipe downward at a slope of at least
proper drainage. Provide tees plugged on one side for clean-outs.
Leave clearance for servicing, and observe all local sanitary codes.
The condensate trap should have a depth adequate to allow 3-in. of
water in the trap with the unit running. See Fig. 15.
MINIMUM PITCH
1/4 IN. PER
FT OF LINE
OPEN
VENT
NOTE: Trap should be deep enough to offset maximum unit static
difference. A 4-in. trap is recommended.
Fig. 15 — External Trap Condensate Drain
Step 6 — Complete Electrical Connections

GENERAL

Verify that nameplate electrical requirements match available
power supply. See Tables 2 and 3. Voltage at condenser must be
within the minimum and maximum shown in Table 2 and phases
must be balanced within 2%. Contact local power company for
line voltage corrections. Never operate a motor where a phase im-
balance in supply voltage is greater than 2%.
Use the following formula to determine the percentage of voltage
imbalance:

UNBALANCED 3-PHASE SUPPLY VOLTAGE

Use the following formula to determine the percent of voltage
imbalance.
Percent Voltage Imbalance
max voltage deviation from average voltage
= 100 x
average voltage
/ inches
3
4
/ -in. per ft for
1
4
TO UNIT
SEE
NOTE
DRAIN
PLUG
Example: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
Average Voltage =
Determine maximum deviation from average voltage:
(AB) 457 – 452 = 5 v
(BC) 464 – 457 = 7 v
(AC) 457 – 455 = 2 v
Maximum deviation is 7 v.
Determine percent of voltage imbalance:
% Voltage Imbalance = 100 x
= 1.53%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
IMPORTANT: If supply voltage phase imbalance is more than
2%, contact your local electric utility company immediately.
Unit operation on improper line voltage or excessive phase imbal-
ance may be considered abuse and any resulting damage may not
be covered by Carrier warranty.
All wiring must be in accordance with local or NEC (National
Electrical Code) regulations.

POWER WIRING

The units must have adequate overcurrent protection, fuses, or
HACR (Heating, Air Conditioning and Refrigeration) breakers,
according to the national and applicable local codes.
For field power connections, all main power wiring enters the unit
through a factory-punched access hole on the side of the control
box. Attach power wires to the power connections on the main
power terminal block in the unit control box. Be sure to install a
ground wire.

CONTROL WIRING

All units require an accessory thermostat package to complete the
unit control system. For a room-mounted thermostat, the thermo-
stat may be mounted in an appropriate location in the conditioned
space. Never locate the thermostat in direct path of air discharge.
Route the wires from the thermostat to the low voltage connection
of the control box. Connect wires to the low voltage terminal
block. See Fig. 16. The fan switch on the thermostat will control
fan operations.

WINTER START MODIFICATIONS

When starting air-cooled units under low-ambient temperature
conditions, the compressor may pull suction pressure down below
the low-pressure cutout switch setting causing the compressor to
shut off. At extremely low temperatures, the low-pressure switch
may open during the off cycle, preventing the compressor from
starting. The use of the winter start kit is recommended. This kit
bypasses the low-pressure switch on start-up for 90 seconds.
16
452 + 464 + 455
3
1371
=
3
= 457
7
457