Lennox ML296UHV(X) Series User manual

Page 1 ©2019 Lennox Industries Inc.
Corp. 1903-L1 ML296UHV(X)
Service Literature
ML296UHV(X) SERIES UNITS
ML296UHV(X) series units are 90% efficiency gas fur
naces used for upflow or horizontal applications only,
manufactured with Lennox Duraloktheat exchangers
formed of aluminized steel. ML296UHV(X) units are avail
able in heating capacities of 44,000 to 132,000 Btuh and
cooling applications up to 5 tons. Refer to Engineering
Handbook for proper sizing.
Units are factory equipped for use with natural gas. Kits are
available for conversion to LPG operation. ML296UHV(X)
unit meets the California Nitrogen Oxides (NOx) Standards
and California Seasonal Efficiency requirements. All units
use a redundant gas valve to assure safety shut-off as re
quired by C.S.A.
All specifications in this manual are subject to change. Pro
cedures outlined in this manual are presented as a recom
mendation only and do not supersede or replace local or
state codes. In the absence of local or state codes, the
guidelines and procedures outlined in this manual (except
where noted) are recommendations only and do not consti
tute code.
TABLE OF CONTENTS
Specifications Page 2.............................
Blower Data Page 3..............................
I Unit Components Page 9........................
II Installation Page 21.............................
III Start Up Page 43..............................
IV Heating System Service Checks Page 44.........
V Typical Operating Characteristics Page 47.........
VI Maintenance Page 47..........................
VII Wiring and Sequence of Operation Page 50......
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person
al injury or loss of life. Installation and service must
be performed by a licensed professional HVAC in
staller (or equivalent), service agency or the gas sup
plier.
CAUTION
As with any mechanical equipment, contact with
sharp sheet metal edges can result in personal in
jury. Take care while handling this equipment and
wear gloves and protective clothing.

Page 2
SPECIFICATIONS
Gas
Heating
Performance
Model No. ML296UH045XV36B ML296UH070XV36B
AHRI Reference No. N/A N/A
1AFUE 96% 96%
High
Fire
Input - Btuh 44,000 66,000
Output - Btuh 42,000 62,000
Temperature rise range - °F 35 - 65 50 - 80
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
3.5 / 10.0 3.5 / 10.0
Low
Fire
Input - Btuh 29,000 43,000
Output - Btuh 28,000 41,000
Temperature rise range - °F 20 - 50 25 - 55
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
1.7 / 4.9 1.7 / 4.9
High static - in. w.g. Heating 0.8 0.8
Cooling 1.0 1.0
Connections
in.
Intake / Exhaust Pipe (PVC) 2 / 2 2 / 2
Gas pipe size IPS 1/2 1/2
Condensate Drain Trap (PVC pipe) - i.d. 3/4 3/4
with furnished 90° street elbow 3/4 slip x 3/4 Mipt 3/4 slip x 3/4 Mipt
with eld supplied (PVC coupling) - o.d. 3/4 slip x 3/4 MPT 3/4 slip x 3/4 MPT
Indoor
Blower
Wheel nominal diameter x width - in. 10 x 9 10 x 9
Motor output - hp 1/2 1/2
Tons of add-on cooling 2 - 3 2 - 3
Air Volume Range - cfm 485 - 1370 500 - 1365
Electrical Data Voltage 120 volts - 60 hertz - 1 phase
Blower motor full load amps 7.7 7.7
Maximum overcurrent protection 15 15
Shipping Data lbs. - 1 package 130 138
NOTE - Filters and provisions for mounting are not furnished and must be eld provided.
1 Annual Fuel Utilization E󰀩ciency based on DOE test procedures and according to FTC labeling regulations. Isolated combustion system rating for non-weatherized furnaces.
Gas
Heating
Performance
Model No. ML296UH090XV48C ML296UH110XV60C
AHRI Reference No. N/A N/A
1AFUE 96% 96%
High
Fire
Input - Btuh 88,000 110,000
Output - Btuh 84,000 106,000
Temperature rise range - °F 45 - 75 45 - 75
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
3.5 / 10.0 3.5 / 10.0
Low
Fire
Input - Btuh 57,000 72,000
Output - Btuh 55,000 70,000
Temperature rise range - °F 30 - 60 35 - 65
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
1.7 / 4.9 1.7 / 4.9
High static - in. w.g. Heating 0.8 0.8
Cooling 1.0 1.0
Connections
in.
Intake / Exhaust Pipe (PVC) 2 / 2 2 / 2
Gas pipe size IPS 1/2 1/2
Condensate Drain Trap (PVC pipe) - i.d. 3/4 3/4
with furnished 90° street elbow 3/4 slip x 3/4 Mipt 3/4 slip x 3/4 Mipt
with eld supplied (PVC coupling) - o.d. 3/4 slip x 3/4 MPT 3/4 slip x 3/4 MPT
Indoor
Blower
Wheel nominal diameter x width - in. 11 x 11 11 x 11
Motor output - hp 3/4 1
Tons of add-on cooling 2.5 - 4 3 - 5
Air Volume Range - cfm 680 - 1770 790 - 1955
Electrical Data Voltage 120 volts - 60 hertz - 1 phase
Blower motor full load amps 10.1 12.8
Maximum overcurrent protection 15 20
Shipping Data lbs. - 1 package 163 174
NOTE - Filters and provisions for mounting are not furnished and must be eld provided.
1 Annual Fuel Utilization E󰀩ciency based on DOE test procedures and according to FTC labeling regulations. Isolated combustion system rating for non-weatherized furnaces.

Page 3
BLOWER DATA
ML296UH045XV36B BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
“ADJUST”
Switch
Positions
Speed Switch Positions
Second Stage “HEAT” Speed - cfm Second Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 745 875 990 1005 905 1075 1210 1370
1NORM 685 765 895 910 815 980 1120 1255
— 610 695 785 810 720 885 1020 1135
“ADJUST”
Switch
Positions
First Stage “HEAT” Speed - cfm First Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 685 765 895 910 595 760 865 980
1NORM 620 705 800 820 540 660 785 890
— 545 625 715 725 485 600 695 790
1 Factory default jumper setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT speed position.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed
position. Continuous Fan Only speed is approximately 38%of the same second stage COOL speed position - minimum
500 cfm. Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 453 cfm.
BLOWER DATA
ML296UH045XV36B BLOWER PERFORMANCE (less lter)
SINGLE SIDE RETURN AIR
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
“ADJUST”
Switch
Positions
Speed Switch Positions
Second Stage “HEAT” Speed - cfm Second Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 780 880 990 1010 920 1065 1205 1340
1NORM 705 795 905 925 815 985 1110 1245
— 640 715 805 810 745 890 1020 1130
“ADJUST”
Switch
Positions
First Stage “HEAT” Speed - cfm First Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 705 795 905 925 610 760 845 975
1NORM 645 725 810 815 550 680 770 880
— 570 655 735 750 465 610 720 775
1 Factory default jumper setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT speed position.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed
position. Continuous Fan Only speed is approximately 38%of the same second stage COOL speed position - minimum
500 cfm. Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 453 cfm.

Page 4
BLOWER DATA
ML296UH045XV36B BLOWER PERFORMANCE (less lter)
SINGLE SIDE RETURN AIR
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
“ADJUST”
Switch
Positions
Speed Switch Positions
Second Stage “HEAT” Speed - cfm Second Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 780 880 990 1010 920 1065 1205 1340
1NORM 705 795 905 925 815 985 1110 1245
— 640 715 805 810 745 890 1020 1130
“ADJUST”
Switch
Positions
First Stage “HEAT” Speed - cfm First Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 705 795 905 925 610 760 845 975
1NORM 645 725 810 815 550 680 770 880
— 570 655 735 750 465 610 720 775
1 Factory default jumper setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT speed position.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed
position. Continuous Fan Only speed is approximately 38%of the same second stage COOL speed position - minimum
500 cfm. Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 453 cfm.
BLOWER DATA
ML296UH070XV36B BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
“ADJUST”
Switch
Positions
Speed Switch Positions
Second Stage “HEAT” Speed - cfm Second Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 965 1130 1255 1400 860 1060 1215 1365
1NORM 880 990 1140 1295 810 960 1130 1265
— 810 890 1030 1170 705 840 1005 1140
“ADJUST”
Switch
Positions
First Stage “HEAT” Speed - cfm First Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 940 1070 1195 1345 600 740 840 970
1NORM 830 965 1100 1235 555 665 770 855
— 755 840 975 1130 500 600 680 790
1 Factory default jumper setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT speed position.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed
position. Continuous Fan Only speed is approximately 38%of the same second stage COOL speed position - minimum
500 cfm. Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 453 cfm.

Page 5
BLOWER DATA
ML296UH070XV36B BLOWER PERFORMANCE (less lter)
SINGLE SIDE RETURN AIR
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
“ADJUST”
Switch
Positions
Speed Switch Positions
Second Stage “HEAT” Speed - cfm Second Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 980 1095 1225 1395 840 1050 1205 1355
1NORM 855 1005 1120 1250 750 945 1130 1230
— 755 870 1020 1170 685 805 990 1110
“ADJUST”
Switch
Positions
First Stage “HEAT” Speed - cfm First Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 920 1055 1205 1325 590 705 805 955
1NORM 800 950 1075 1215 540 640 725 820
— 730 810 960 1095 500 580 665 720
1 Factory default jumper setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT speed position.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed
position. Continuous Fan Only speed is approximately 38%of the same second stage COOL speed position - minimum
500 cfm. Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 453 cfm.
BLOWER DATA
ML296UH070XV36B BLOWER PERFORMANCE (less lter)
SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
“ADJUST”
Switch
Positions
Speed Switch Positions
Second Stage “HEAT” Speed - cfm Second Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 975 1095 1245 1385 855 1045 1205 1350
1NORM 870 995 1130 1280 790 945 1090 1255
— 790 885 1010 1155 720 845 985 1130
“ADJUST”
Switch
Positions
First Stage “HEAT” Speed - cfm First Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 925 1050 1175 1330 595 715 815 950
1NORM 810 945 1070 1220 520 655 755 840
— 730 840 955 1095 490 595 670 745
1 Factory default jumper setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT speed position.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed
position. Continuous Fan Only speed is approximately 38%of the same second stage COOL speed position - minimum
500 cfm. Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 453 cfm.

Page 6
BLOWER DATA
ML296UH090XV48C BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTTOM AND ONE SIDE
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
“ADJUST”
Switch
Positions
Speed Switch Positions
Second Stage “HEAT” Speed - cfm Second Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 1230 1310 1360 1605 1165 1375 1580 1770
1NORM 1115 1195 1255 1455 1075 1265 1440 1645
— 1005 1070 1130 1335 935 1145 1320 1465
“ADJUST”
Switch
Positions
First Stage “HEAT” Speed - cfm First Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 1165 1250 1315 1520 840 1005 1155 1315
1NORM 1075 1140 1195 1405 780 915 1045 1190
— 935 1030 1065 1285 690 835 955 1070
1 Factory default jumper setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT speed position.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed
position. Continuous Fan Only speed is approximately 38%of the same second stage COOL speed position - minimum
500 cfm. Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 453 cfm.
BLOWER DATA
ML296UH090XV48C BLOWER PERFORMANCE (less lter)
SINGLE SIDE RETURN AIR
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
“ADJUST”
Switch
Positions
Speed Switch Positions
Second Stage “HEAT” Speed - cfm Second Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 1210 1275 1320 1555 1140 1340 1525 1725
1NORM 1115 1175 1230 1400 1040 1235 1395 1565
— 990 1070 1125 1295 910 1120 1275 1400
“ADJUST”
Switch
Positions
First Stage “HEAT” Speed - cfm First Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 1140 1230 1280 1455 820 1005 1135 1290
1NORM 1040 1135 1180 1370 755 880 1025 1150
— 910 1000 1075 1250 680 815 925 1065
1 Factory default jumper setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT speed position.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed
position. Continuous Fan Only speed is approximately 38%of the same second stage COOL speed position - minimum
500 cfm. Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 453 cfm.

Page 7
BLOWER DATA
ML296UH110XV60C BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTTOM AND ONE SIDE
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
“ADJUST”
Switch
Positions
Speed Switch Positions
Second Stage “HEAT” Speed - cfm Second Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 1560 1760 1905 2080 1312 1560 1744 1955
1NORM 1415 1610 1740 1930 1219 1405 1569 1796
— 1285 1485 1560 1745 1075 1272 1428 1634
“ADJUST”
Switch
Positions
First Stage “HEAT” Speed - cfm First Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 1155 1325 1420 1565 937 1064 1247 1407
1NORM 1055 1200 1310 1480 864 972 1146 1282
— 935 1075 1170 1315 790 888 1025 1167
1 Factory default jumper setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT speed position.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed
position. Continuous Fan Only speed is approximately 38%of the same second stage COOL speed position - minimum
500 cfm. Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 478 cfm.
BLOWER DATA
ML296UH110XV60C BLOWER PERFORMANCE (less lter)
SINGLE SIDE RETURN AIR − Air volumes in bold (over 1800 cfm) require Optional Return Air Base and eld fabricated transition
to accommodate 20 x 25 x 1 in. air lter in order to maintain proper air velocity.
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
“ADJUST”
Switch
Positions
Speed Switch Positions
Second Stage “HEAT” Speed - cfm Second Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 1530 1735 1845 2025 1270 1519 1712 1899
1NORM 1380 1555 1705 1860 1170 1363 1555 1774
— 1235 1440 1540 1710 1059 1218 1401 1581
“ADJUST”
Switch
Positions
First Stage “HEAT” Speed - cfm First Stage “COOL” Speed - cfm
D1C B A D C B 1A
+ 1140 1280 1390 1550 918 1053 1198 1366
1NORM 1040 1175 1260 1430 820 964 1095 1231
— 910 1080 1150 1265 722 852 987 1116
1 Factory default jumper setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT speed position.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed
position. Continuous Fan Only speed is approximately 38%of the same second stage COOL speed position - minimum
500 cfm. Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 478 cfm.

Page 8
FIGURE 1
ML296UHV PARTS IDENTIFICATION
Burner Box Assembly
Gas Valve
Heat Exchanger
Combustion
Air Inducer Pressure
Switch
Assembly
Primary Limit
Variable Speed Motor
Two-Stage Integrated Control
Access Panel
Bag Assemblies
(shipping location)
Field Make Up Box
Door
Interlock
Switch

Page 9
I-UNIT COMPONENTS
ML296UHV(X) unit components are shown in figure 1. The
gas valve, combustion air inducer and burners can be ac
cessed by removing the access panel. Electrical compo
nents are in the control box (figure 2) found in the blower
section.
CAUTION
Electrostatic discharge can affect elec
tronic components. Take precautions
to neutralize electrostatic charge by
touching your hand and tools to metal
prior to handling the control.
A- Control Box
1. Control Transformer (T1)
A transformer located in the control box provides power to
the low voltage section of the unit. Transformers on all
models are rated 40VA with a 120V primary and a 24V sec
ondary.
2. Door Interlock Switch (S51)
A door interlock switch rated 14A at 125VAC is wired in se
ries with line voltage. When the inner blower access panel
is removed the unit will shut down.
FIGURE 2
Control Box Components
Integrated Control
Door Interlock Switch
Transformer
WARNING
Shock hazard.
Disconnect power before servicing. Integrated
control is not field repairable. If control is inoper
able, simply replace entire control.
Can cause injury or death. Unsafe operation will re
sult if repair is attempted.
3. Integrated Control (A92)
Units are equipped with a two-stage, variable speed inte
grated control. The system consists of a ignition / blower
control (figure 3) with control pin designations in tables 3
and 4 and ignitor. The control and ignitor work in combina
tion to ensure furnace ignition and ignitor durability. The
control provides gas ignition, safety checks and indoor
blower control with two-stage gas heating. The furnace
combustion air inducer, gas valve and indoor blower are
controlled in response to various system inputs such as
thermostat signal, pressure and limit switch signal and
flame signal.
The furnace has a built-in, self-diagnostic capability. If a
system problem occurs, a fault code is shown by a red LED
on the control. The control continuously monitors its own
operation and the operation of the system. If a failure oc
curs, the LED will indicate the failure code. The flash codes
are presented in table 2.
Fault Code History Button
The control stores the last five fault codes in memory. A
pushbutton switch is located on the control. When the
pushbutton switch is pressed and released, the control
flashes the stored fault codes. The most recent fault code is
flashed first; the oldest fault code is flashed last. To clear
the fault code history, press and hold the pushbutton switch
in for more than 5 seconds before releasing.
Single Stage Thermostat Operation
The automatic heat staging option allows a single stage
thermostat to be used with two stage furnace models. To
activate this option, move the jumper pin (see Figure 3) to
desired setting (5 minutes or 10 minutes). The furnace will
start on 1st stage heat and stay at 1st stage heat for the
duration of the selected time before switching to 2nd stage
heat.
W1 on the integrated control must be connected to W1 on
the thermostat.
High Heat State LED
A green LED is provided on the control board to indicate
high heat state
(see Table 1).
CFM LED
An amber LED is provided on the control board to display
CFM. To determine what CFM the motor is delivering at any
time, count the number of times the amber LED flashes.
Each flash signifies 100 CFM; count the flashes and multi
ply by 100 to determine the actual CFM delivered (for ex
ample: 5 flashes x 100 = 500 CFM).

Page 10
TABLE 1
High Heat State Green LED
LED Status DESCRIPTION
LED Off No demand for high heat
LED On High heat demand, operating normally
LED Flashing High heat demand, high pressure
switch not closed
TABLE 2
Diagnostic Codes Red LED
LED Status DESCRIPTION
LED Off No power to control or control harware
fault detected.
LED On Normal operation.
1 Flash Flame present with gas vavle
de-energized.
2 Flashes Pressure switch closed with combustion
air inducer de-energized.
3 Flashes Low-fire pressure, rollout or limit
switch open.
4 Flashes Primary limit switch open.
5 Flashes Not used
6 Flashes Pressure switch cycle lockout.
7 Flashes Lockout, burners fail to light.
8 Flashes Lockout, buners lost flame too many
times.
9 Flashes Line voltage polarity incorrect.
TABLE 3
Control 5 Pin Terminal Designation
PIN # Function
1Ignitor (Hot)
2Combustion Air Inducer High Speed
3Combustion Air Inducer Low Speed
4Combustion Air Inducer Neutral
5Ignitor Neutral
Airflow Adjustments
Cooling Mode
The units are factory set for the highest airflow for each model.
Adjustments can be made to the cooling airflow by reposi
tioning the jumper plug marked COOL – A, B, C, D (see Fig
ure 3).  To determine what CFM the motor is delivering at
any time, count the number of times the amber LED on the
control board flashes. Each flash signifies 100 CFM; count
the flashes and multiply by 100 to determine the actual CFM
delivered (for example: 5 flashes x 100 = 500 CFM).
TABLE 4
12 Pin Terminal Designation
PIN # Function
1Gas Valve Second Stage
2Second Stage Prove Switch
3Rollout Switch In
4 Ground
524V Hot
6Primary Limit In
7Gas Valve First Stage
8Gas Valve Common
924V Neutral
10 Ground
11 Rollout Switch Out
12 First Stage Prove Switch
Heating Mode
These units are factory set to run at the middle of the heating
rise range as shown on the unit rating plate. If higher or lower
rise is desired, reposition the jumper plug marked HEAT - A,
B, C, C (see Figure 3) . To determine what CFM the motor is
delivering at any time, count the number of times the amber
LED on the control board flashes. Each flash signifies 100
CFM; count the flashes and multiply by 100 to determine the
actual CFM delivered (for example: 5 flashes x 100= 500.
Adjust Tap
Airflow amounts may be increased or decreased by 10% by
moving the ADJUST jumper plug (see Figure 3) from the
NORM position to the (+) or (-) position. Changes to the AD
JUST tap will affect both cooling and heating airflows. The
TEST position on the ADJUST tap is not used.
Continuous Blower Operation
The comfort level of the living space can be enhanced
when using this feature by allowing continuous circulation
of air between calls for cooling or heating. The circulation of
air occurs at half the full cooling airflow rate.
To engage the continuous blower operation, place the fan
switch on the thermostat into the ON position. A call for fan
from the thermostat closes R to G on the ignition control
board. The control waits for a 1 second thermostat delay
before responding to the call for fan by ramping the circulat
ing blower up to 50% of the cooling speed. When the call for
continuous fan is satisfied, the control immediately ramps
down the circulating blower.