Carrier SINGLE PACKAGE ROOFTOP UNITS 48PG20-28 - Manual (Page 15)

15
LEGEND AND NOTES FOR TABLES 4A AND 4B
LEGEND
*Fuse or HACR circuit breaker.
NOTES:
1. In compliance with NEC requirements for multimotor and com-
bination load equipment (refer to NEC Articles 430 and 440),
the overcurrent protective device for the unit shall be fuse or
HACR breaker. Canadian units may be fuse or circuit breaker.
2. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply volt-
age is greater than 2%. Use the following formula to determine
the percent voltage imbalance.
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 voltage imbalance.
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
3. The convenience outlet full load amps (FLA) are 5, 3, and 3 for
208/230, 460, 575-V units, respectively.
FLA — Full Load Amps
HACR — Heating, Air Conditioning and Refrigeration
IFM
— Indoor (Evaporator) Fan Motor
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
MOCP — Maximum Overcurrent Protection
NEC
— National Electrical Code
OFM — Outdoor (Condenser) Fan Motor
RLA — Rated Load Amps
% Voltage Imbalance
= 100 x
max voltage deviation from average voltage
average voltage
EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
Average Voltage=
452 + 464 + 455
3
=
1371
3
= 457
% Voltage Imbalance = 100 x
7
457
= 1.53%
IMPORTANT: If the supply voltage phase imbalance is more
than 2%, contact the local electric utility company immediately.
TOP HOOD
SECTION
SEAL
STRIP
LOCATION
BOTTOM
HOOD
SECTION
FILTER
GUIDE
FILTER
GUIDE
HOOD
SIDE
ADD
SEAL
STRIP
ADD
SEAL
STRIP
HOOD
SIDE
INNER
FILTER
TRACK
ADD
SEAL
STRIP
ADD
SEAL
STRIP
UNIT
BACK
PANEL
FILTER
RETAINER
FILTER
MANUAL
DAMPER
(IF EQUIPPED)
NOTE: Units with manual damper only use one filter.
Fig. 18 — Outdoor-Air Hood Details