Carrier WEATHERMAKER 48A3 - Gas Piping and Field Wiring; Field Gas Piping Diagram; Field Power Wiring Diagrams

19
Table 7 — 48A Series Staged Gas Control
FIELD POWER SUPPLY — Unit is factory wired for volt-
age shown on unit nameplate. See Tables 8A and 8B for elec-
trical data.
Field wiring can be brought into the unit from bottom
(through basepan and roof curb) or through side of unit (corner
post next to control box).
A 3
1
/
2
-in. NPT coupling for field power wiring and a
3
/
4
-in.
NPT coupling for 24-v control wiring are provided in basepan.
In the side post, there are two 2
1
/
2
-in. (sizes 020-035) or 3-in.
(sizes 040-060) knockouts for the field power wiring. See
Fig. 4-9. If control wiring is to be brought in through the side of
unit, a
7
/
8
-in. diameter hole is provided in the condenser side
post next to the control box.
Do not route control wiring in the same conduit as power
wiring.
If disconnect box is mounted to corner post, be careful not
to drill or screw into the condenser coil.
LEGEND AND NOTES FOR TABLES 8A AND 8B
LEGEND
*Fuse or HACR circuit breaker per NEC.
NOTES:
1. In compliance with NEC requirements for multimotor and combination load
equipment (refer to NEC Articles 430 and 440), the overcurrent protective
device for the unit shall be fuse or HACR breaker. The Canadian units may
be fuse or circuit breaker.
2. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply voltage is
greater than 2%. Use the following formula to determine the percent of volt-
age imbalance.
% Voltage imbalance
Example: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
= 457
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%.
NUMBER OF
STAGES
MODEL NUMBER POSITION
HEAT SIZE
5 6,7,8
5 stages
S
020
025
027
030
035
040
050
Low
T
035
040
050
High
7 stages T
020
025
027
030
High
9 stages T 060 High
11 stages S 060 Low
Fig. 18 — Field Gas Piping
a48-2524
FIELD SUPPLIED
DISCONNECT PER NEC
FIELD
POWER
SUPPLY
11
21
22
23
13
12
TB1
EQUIP GND
FIELD POWER WIRING
11
21
22
23
13
12
GND
OPTIONAL
FACTORY-INSTALLED
DISCONNECT
FIELD-INSTALLED DISCONNECT
FACTORY-INSTALLED DISCONNECT
LEGEND
GND — Ground
NEC — National Electrical Code
TB — Terminal Block
Fig. 19 — Field Power Wiring Connections
a48-6977
FLA — Full Load Amps
HACR — Heating, Air Conditioning and Refrigeration
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
MCHX — Microchannel Heat Exchanger
MOCP — Maximum Overcurrent Protection
NEC — National Electrical Code
RLA — Rated Load Amps
RTPF — Round Tube Plate Fin Coil
= 100 x
max voltage deviation from average voltage
average voltage
Average Voltage =
452 + 464 + 455
3
=
1371
3
IMPORTANT: If the supply voltage phase imbalance is more than 2%,
contact your local electric utility company immediately.
7
457