Carrier GT-G Series Guide

InternalAuxiliary Electric Heat
Installation, Operation & Maintenance Instructions
Revision 1/99
Overview
The GT-G Series Auxiliary Electric Heat mounts internally on
any GT-G upflow (Figure 1) or downflow unit and mounts
directly on the blower outlet of all horizontal GT-G units
(Figure 6). Note the model compatibility Table 2. Horizontal
units are rated for zero clearance at the unit and 1" clearance
for first three feet of duct, vertical units rated for zero clearance
for both unit and duct. Downflow units can not be located
directly over a discharge register. The discharge plenum must
make a 90°turn after leaving the unit and be constructed from
non combustible material. The GT-G electric heat contains a
four stage relay control board which activates the elements
directly via an internally wired low voltage harness. Low
voltage signals (W1 and W2) are staged from the CXM or
DXM control of the GT-G unit. It should be noted that only
distributor model GT-G units are prewired for low voltage
control of the electric heat. Carrier Tech Support should
be contacted for use on all other models.
Vertical Upflow or Downflow Installation
1. Disconnect power to the unit
2. Remove blower access panels.
3. Clip wire-tie holding electric heat low voltage 3-wire
harness to discharge panel stiffener. Refer to Figure 1.
4. Remove blower mounting screws and then drop down
blower assembly as shown in Figure 2. Removal of blower
wires should not be necessary.
5. Install electric heat in discharge flange where blower
assembly has been removed using provided screws as
shown In Figure 3.
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Auxiliary electric heat
power supply knockout
opposite air coil
Electric Heat Assembly
Air Coil
Low Voltage control
harness is prewired
on all distributor class
Genesis
Remove screws &
drop blower
Locate electric heat assembly
on pins in discharge panel
and insert screws
Relocate blower in electric
heat assembly in same
manner
Figure 2. Blower removal.
Figure 3. GT-G electric heat mounting and blower
re-installation.
Figure 1. Typical vertical unit installation.
Note: For AGMelectric heaters remove control box from
houseing by removing the control box cover and then removing
the four (4) screws (do not discard) that hold the control box to
the housing. Allow the control box to hang on the wire tie
located in the housing flange. After completing step 5 replace
the control box on the housing.
GT-G Series
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Page 2
Auxiliary electric heat power
supply knockout opposite air coil
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Electric Heat Assembly
Disconnect (optional
refer to local code)
Route conduit thru cabinet and
connect to electric heat control
box. Seal to eliminate air leaks on
cabinet exterior.
6. Re-install blower assembly, Figure 3, into electric heat
assembly using blower mounting screws. Check blower
wiring for proper wiring connections.
7. Route the low voltage harness through the provided ‘pie’
bushing and plug into electric heat control board connector
P2 as shown in Figure 4.
8. Install power conduit, Figure 5, through unit corner post
knockout and attach conduit directly to the electric heat
control box.
Horizontal Installation
1. Disconnect power to the unit
2. Remove blower access panels.
3. Clip wire-tie holding electric heat low voltage 3-wire
harness to discharge panel stiffener.
4. Remove blower discharge flange screws and remove the
two flanges and discard them but save the screws.
5. Install electric heat in discharge flange mounting where
discharge flange had been removed using the old screws.
6. Route the low voltage harness through unit discharge panel
knockout and seal penetration 'air tight'.
7. Then route the harness through the provided ‘pie’ bushing
in the electric heat control box and plug into electric heat
control board connector P2 as shown.
8. Install power conduit and attach directly to the electric heat
control box.
Wiring and Setup (all models)
ON
OFF
ON
OFF
1234 P1
In 12, 15 and 20 kW units
two power circuits are
employed to reduce wires
size and cost of breakers
L1
L2
L3
L4
P2
Conduit
L2
L1
Conduit
In 12, 15 and 20 kW units, optional
single power circuitb is employed to
reduce the number of wires needed.
Conduit
OFF
OFF
L1
L2
L3
L4
L1
L2
1234 P1
ON
OFF
ON
OFF
Locate electric heat
harness in air handler
and route through
provided bushing
Connect 5 pin low
voltage connector
to board
P2
Remove discharge flange and
replace with horizontal auxiliary
electric heat
Optional disconnect
refer to local codes
Figure 4. Low Voltage Harness Connection
Figure 5. Power Conduit And Wire Routing
Figure 7a. Power Wiring, Dual Circuits, 12, 15, 20kw
Figure 6. Typical Horizontal Installation
Figure 7b. Power
Wiring, Single Circuit,
12, 15, 20kw
Figure 7c. Power Wiring,
4, 5, 8, And 10kw

Page 3
9. Install power wiring and connect to power block or circuit
breakers. In 12, 15 or 20kW models two power circuits
may be used to reduce wiring and breaker costs as in
Figure 7a. If a single circuit supply is desired, install the
optional single circuit accessory kit, as shown in Figure 7b,
that can be obtained from your Carrier distributor.
10. Check unit CFM of Table 1 and ensure airflow setting is
above minimum airflow rating for the electric heat model
from Table 2. Low speed blower not allowed with
electric heat.
11. Check staging jumpers for the application. Typically only
5 kW (factory setting on all models except 10kW on 20kW
models) is needed for first stage electric (W1) to minimize
electric demand. This staging can be adjusted by moving
the staging jumpers as shown in Figure 8.
12. Mark the appropriate box of the electric heat model
installed on the additional serial plate on the exterior of the
unit.
13. Turn on the power to the unit and the auxiliary electric
heat.
Auxiliary Electric Heat Start-up
14. Run thermostat to emergency heat mode (or jumper t-stat
input R to W) and setpoint to high setting. ‘Touch-jumper'
the test pins of the CXM or DXM into test mode to reduce
time delays. Unit will require 15-20 seconds before
engaging emergency heat mode stage 1 (W1) and then
another 15-20 seconds to engage stage 2 (W2) when in
‘Test mode’. Verify proper electric heat operation.
NO
Com ER1
NO
Com ER2
NO
Com ER3
NO
Com ER4
123
Tan
Ora
Factory Staging
(see Table 2)
Low Voltage Connector
(from Unit Control Board)
Genesis Electric
Heat Relay Board P1P2
24V
W1
W2
4
Staging Example on a 15kW unit W1 (first stage) has
5kW (‘ER1’ 5kW & ‘ER4’ 0kW) and W2 (second stage)
will have 10kW (‘ER2 & 3’ 5kW each)
1234
Tan
Ora
P2
Side View as seen in Control Box
P1
Figure 8. Staging Jumpers
Table 1. GT-G PSC Blower Performance Table
GT-G Electric
Heat Relay Board
GT-G
Series Fan Airflow (cfm) at External Static Pressure (in. wg)
0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.60 0.70 0.80 0.90 1.00
50YCG Future Product - Data Not Available
50YCG Future Product - Data Not Available
H 781 771 764 757 748 740 718 697 665 638 610 - - - -
50YCG M 739 719 710 702 688 675 658 641 619 598 - - - - -
L* 626 613 605 597 589 581 566 551 531 512 - - - - -
H 781 771 764 757 748 740 718 697 665 638 610 - - - -
50YCG M 739 719 710 702 688 675 658 641 619 598 - - - - -
L* 626 613 605 597 589 581 566 551 531 512 - - - - -
H 1066 1038 1010 983 954 926 900 874 838 803 707 - - - -
50YCG M 902 886 870 854 831 809 782 756 726 702 - - - - -
L* 797 779 761 738 726 709 683 657 634 606 - - - - -
H 1173 1152 1125 1104 1081 1058 1033 1007 984 955 841 - - - -
50YCG M 1085 1061 1037 1013 975 938 916 894 864 830 - - - - -
L* 939 924 909 894 871 853 827 802 779 752 - - - -
H 1358 1330 1291 1258 1225 1198 1162 1132 1094 1057 965 858 - - -
50YCG M 1216 1193 1166 1143 1112 1082 1050 1023 982 941 - - - - -
L* 1069 1059 1049 1039 1021 999 975 952 925 899 - - - - -
H - - 1780 1700 1622 1612 1580 1544 1491 1434 1343 1211 - - -
50YCG M 1546 1524 1502 1480 1450 1426 1396 1371 1333 1294 - - - - -
L* 1217 1205 1193 1181 1168 1156 1128 1100 1063 1031 - - - - -
H - - 1893 1851 1807 1768 1718 1664 1630 1596 1454 1322 1195 - -
50YCG M 1744 1699 1664 1624 1578 1532 1498 1468 1419 1376 - - - - -
L* 1362 1336 1314 1298 1275 1252 1219 1187 1152 1112 - - - - -
H - - - - 2222 2197 2167 2137 2106 2076 2019 1941 1839 1705 1641
50YCG M 2135 2113 2090 2068 2045 2022 2004 1981 1950 1924 1871 1869 - - -
L* 1909 1890 1876 1862 1841 1825 1803 1787 1762 1733 - - - - -
H - - - - 2501 2477 2439 2400 2370 2345 2275 2205 2061 1921 1779
50YCG M 2465 2432 2403 2380 2353 2331 2304 2278 2250 2223 2158 2076 - - -
L* 2132 2117 2107 2092 2069 2052 2031 2001 1976 1940 - - - - -
Includes allowance for wet coil and clean factory-installed filter
Factory settings are indicated in bold print
(-) operation not recommended
* Electric Heat operation not allowed with blower motor set at low speed
Model Snd

Genesis Supply Heater Amps Min Circ Ampacity Max Fuse
Supply Wire
Electric Heat Model Circuit 240V 208V 240V 208V 240V 208V Min AWG Max Ft
AGS4 or AGSH4 Single 15.8 13.7 19.8 17.1 20 20 12 50
AGM5 or AGMH5 Single 20.0 17.3 25.0 21.6 25 25 10 70
AGM8 or AGMH8 Single 31.7 27.5 39.6 34.4 40 35 8 70
AGM10 or AGMH10 Single 40.0 34.7 50.0 43.4 50 45 6 90
Single 47.5 41.2 59.4 51.5 60 60 6 70
AGM12 or AGMH12 Dual - L1/L3 31.7 27.5 39.6 34.4 40 35 8 70
Dual - L2/L4 15.8 13.7 19.8 17.1 20 20 12 50
AGL10 or AGLH10 Single 40.0 34.7 50.0 43.4 50 45 6 80
Single 60.0 52.0 75.0 65.0 80 70 6 50
AGL15 or AGLH15 Dual - L1/L3 40.0 34.7 50.0 43.4 50 45 6 80
Dual - L2/L4 20.0 17.3 25.0 21.6 25 25 10 70
Single 80.0 69.3 100.0 86.6 100 90 2 100
AGL20 or AGLH20 Dual - L1/L3 40.0 34.7 50.0 43.4 50 45 6 80
Dual - L2/L4 40.0 34.7 50.0 43.4 50 45 6 80
All heaters rated single phase 208-240V 60 Hz Wire length based on one way measurement with 2% voltage drop
Wire size based on 90°C copper conductor Part numbers with "H" included are for horizontal units only
All models 12kW or larger feature internal circuit breakers
Genesis Auxiliary Gensis Model Compatibility (shaded) kW Rating (kW) Btuh Rating (Btuh) Minimum
Electric Heat Model 009 012 015 018 024 030 036 042 048 060 070 240V 208V 240V 208V CFM
Required
AGS4 or AGHS4 3.8 2.9 12900 9700 250
AGM5 or AGMH5 4.8 3.6 16300 12300 500
AGM8 or AGMH8 7.6 5.7 25900 19400 650
AGM10 or AGMH10 9.6 7.2 32700 24600 650
AGM12 or AGMH12 11.4 8.6 38900 29200 750
AGL10 or AGLH10 9.6 7.2 32700 24600 1300
AGL15 or AGLH15 14.4 10.8 49100 36900 1350
AGL20 or AGLH20 19.2 14.4 65500 49200 1350
Note: Horizontal units rated for zero clearance unit and 1" clearance for first three feet of duct, vertical units rated for zero clearance for
both unit and duct.
Table 4. GT-G Electric Heat Staging Options
Table 3. GT-G Electric Heat Electrical Data
Table 2. GT-G Electric Heat Ratings
Carrier works continually to improve its products. As a result, the design and specifications of each product at the time of order may be changed without
notice and may not be as described herein. Please contact Carrier’s Customer Service Department at 1-405-745-6620 for specific information on the
current design and specifications. Statements and other information contained herein are not express warranties and do not form the basis of any bargain
between the parties, but are merely Carrier’s opinion or commendation of its products.
7300 S.W. 44th Street
Oklahoma City, OK 73179
Phone: [phone]
FAX: [phone]
www.Carrier.com
© Carrier 1999
*97B0005N01*
97B0005N01
Genesis Staging Factory Staging in kW
Auxiliary Electric Options Setting Jumper 1-4, 2-3† Jumper 1-3, 2-4 Jumper 1-2-3
Heat Model Stage 1 Stage 1 Stage 2 Stage 1 Stage 2 Stage 1 Stage 2
AGS4 or AGSH4 44404040
AGM5 or AGMH5 55505050
AGM8 or AGMH8 4 or 8 4 4 4 4 4 8 0
AGM10 or AGMH10 5 or 10 5 5 5 5 5 10 0
AGM12 or AGMH12 4, 8 or 12 4 4 8 8 4 12 0
AGL10 or AGLH10 5 or 10 5 5 5 5 5 10 0
AGL15 or AGLH15 5,10 or 15 5 5 10 10 5 15 0
AGL20 or AGLH20 5,10, 15 or 20 10 10 10 10 10 15 5
Part numbers with "H" included are for horizontal units only
†Factory jumper setting
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