Lennox SLP99UHV Series Installation and operation manual

Page 1
UNIT INFORMATIONUNIT INFORMATION
Service Literature
©2016 Lennox Industries, Inc.
WARNING
Improper installation, adjustment, alteration,
service or maintenance can cause property damage,
personal injury or loss of life. Installation and service
must be performed by a licensed professional
HVAC installer or equivalent, service agency, or the
gas supplier.
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at disconnect
switch(es). Unit may have multiple power
supplies.
CAUTION
As with any mechanical equipment, contact with sharp
sheet metal edges can result in personal injury. Take
care while handling this equipment and wear gloves and
protective clothing.
SLP99UHV series units are high-e󰀩ciency upow, hori-
zontal right and left) gas furnaces equipped with variable
capacity gas valve, variable speed combustion air inducer
and variable speed indoor blower motor. All models are
designed only for direct vent (dual pipe) venting system.
SLP99UHV units are available in heating capacities from
66,000 to 132,000 Btuh (19.3 to 38.6 kW) and cooling ap-
plications from 2 to 5 tons (7.0 kW to 17.5 kW). Refer to
Engineering Handbook for proper sizing.
Units are factory-equipped for use with natural gas. Kits
are available for conversion to LPG operation. SLP99UHV
models include a SureLight®variable capacity integrated
control that can be used with a Lennox communicating
thermostat as part of a communicating comfort system.
All SLP99UHV units meet the California Nitrogen Oxides
(NOx) Standards and California Seasonal E󰀩ciency re-
quirements.
All specications in this manual are subject to change.
Procedures outlined in this manual are presented as rec-
ommendations 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 con-
stitute code.
TABLE OF CONTENTS
Specications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
Optional Accessories . . . . . . . . . . . . . . . . . . . . . . Page 3
Blower Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4
I Unit Components . . . . . . . . . . . . . . . . . . . . . . . Page 20
II Communicating Thermostat . . . . . . . . . . . . . . Page 44
III Placement and Installation . . . . . . . . . . . . . . Page 47
IV Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 63
V Heating System Service Checks . . . . . . . . . . Page 60
VI Typical Operating Characteristics . . . . . . . . Page 69
VII Maintenanc . . . . . . . . . . . . . . . . . . . . . . . . . . Page 71
VIII Wiring and Sequence of Operation . . . . . Page 74
XI Field Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . Page 82
SLP99UHV
100001
10/2021
SLP99UHV SERIES UNITS

Page 2
SPECIFICATIONS
Gas
Heating
Performance
Model No. SLP99UH070XV36B SLP99UH090XV36C SLP99UH090XV48C
1AFUE 98.1% 98.1% 98.2%
Maximum Input - Btuh 66,000 88,000 88,000
Output - Btuh 64,000 85,000 85,000
Temperature rise range - °F 50 - 80 60 - 90 50 - 80
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
3.5 / 10.0 3.5 / 10.0 3.5 / 10.0
Minimum Input - Btuh 23,000 31,000 31,000
Output - Btuh 22,000 30,000 30,000
Temperature rise range - °F 35 - 65 35 - 65 35 - 65
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
0.5 / 1.5 0.5 / 1.5 0.5 / 1.5
High static - in. w.g. 0.8 0.8 0.8
Connections
in.
Intake / ² Exhaust Pipe (PVC) 2 / 2 2 / 2 2 / 2
Gas pipe size IPS 1/2 1/2 1/2
Condensate Drain Trap (PVC pipe) - i.d. 3/4 3/4 3/4
with furnished 90° street elbow 3/4 slip x 3/4 Mipt 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 3/4 slip x 3/4 MPT
Indoor
Blower
Wheel nominal diameter x width - in. 10 x 9 10 x 9 11 x 11
Motor output - hp 1/2 1/2 3/4
Tons of add-on cooling 2 - 3 2 - 3.5 2.5 - 4
Air Volume Range - cfm 339 - 1365 520 - 1360 528 - 1770
Electrical Data Voltage (Maximum Amps) 120 volts - 60 Hertz - 1 phase
Blower motor full load amps 7.7 7.7 10.1
Maximum overcurrent protection 15 15 15
Shipping Data lbs. - 1 package 139 156 166
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.
22 in. Rubber Flue Coupling is furnished for exhaust pipe connection to unit.
SPECIFICATIONS
Gas
Heating
Performance
Model No. SLP99UH090XV60C SLP99UH110XV60C SLP99UH135XV60D
1AFUE 99% 98.1% 98.4%
Maximum Input - Btuh 88,000 110,000 132,000
Output - Btuh 87,000 106,000 128,000
Temperature rise range - °F 50 - 80 50 - 80 55 - 85
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
3.5 / 10.0 3.5 / 10.0 3.5 / 10.0
Minimum Input - Btuh 31,000 39,000 46,000
Output - Btuh 30,000 38,000 45,000
Temperature rise range - °F 25 - 55 35 - 65 35 - 65
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
0.5 / 1.5 0.5 / 1.5 0.5 / 1.5
High static - in. w.g. 0.8 0.8 0.8
Connections
in.
Intake / ² Exhaust Pipe (PVC) 2 / 2 2 / 2 2 / 2
Gas pipe size IPS 1/2 1/2 1/2
Condensate Drain Trap (PVC pipe) - i.d. 3/4 3/4 3/4
with furnished 90° street elbow 3/4 slip x 3/4 Mipt 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 3/4 slip x 3/4 MPT
Indoor
Blower
Wheel nominal diameter x width - in. 11 x 11 11 x 11 11 x 11
Motor output - hp 1 1 1
Tons of add-on cooling 3 - 5 3 - 5 3.5 - 5
Air Volume Range - cfm 380 - 2195 580 - 2125 646 - 2190
Electrical Data Voltage (Maximum Amps) 120 volts - 60 Hertz - 1 phase
Blower motor full load amps 12.8 12.8 12.8
Maximum overcurrent protection 20 20 20
Shipping Data lbs. - 1 package 166 176 191
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.
22 in. Rubber Flue Coupling is furnished for exhaust pipe connection to unit.

Page 3
OPTIONAL ACCESSORIES - ORDER SEPARATELY
NOTE - FURNACES CANNOT BE TWINNED!
“B” Width
Models
“C” Width
Models
“D” Width
Models
CABINET ACCESSORIES
Horizontal Suspension Kit - Horizontal only 51W10 51W10 51W10
Return Air Base - Upow only 50W98 50W99 51W00
High Performance Economizer (Commercial Only) 10U53 10U53 10U53
CONDENSATE DRAIN KITS
Condensate Drain Heat Cable 6 ft. 26K68 26K68 26K68
24 ft. 26K69 26K69 26K69
Crawl Space Vent Drain Kit US 51W18 51W18 51W18
Canada 15Z70 15Z70 15Z70
CONTROLS
iComfort®S30 Ultra-Smart Wi-Fi Thermostat 12U67 12U67 12U67
1Remote Outdoor Air Temperature Sensor X2658 X2658 X2658
Night Service Kit 20F44 20F44 20F44
FILTER KITS
2Air Filter and
Rack Kit
Horizontal (end) 87L96 87L97 87L98
Size of lter - in. 18 x 25 x 1 20 x 25 x 1 25 x 25 x 1
Side Return Single 44J22 44J22 44J22
Ten Pack 66K63 66K63 66K63
Size of lter - in. 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1
TERMINATION KITS
Direct Vent Applications Only. See Installation Instructions for specic venting information.
Direct Vent Concentric US - 2 in. 71M80 69M29 - - -
3 in. - - - 60L46 60L46
Canada - 2 in. 44W92 44W92 - - -
3 in. - - - 44W93 44W93
Flush-Mount US - 2, 2-1/2 or 3 in. 51W11 51W11 51W11
Canada - 2, 2-1/2 or 3 in. 51W12 51W12 51W12
Wall - Close Couple US - 2 in. 22G44 - - - - - -
3 in. 44J40 44J40 44J40
Wall - Close Couple WTK Canada - 2 in. 30G28 - - - - - -
3 in. 81J20 81J20 81J20
Roof Termination Flashing Kit
(no vent pipe - 2 ashings)
2 in. 15F75 15F75 - - -
3 in. 44J41 44J41 44J41
1Remote Outdoor Temperature Sensor is used with conventional (non-iComfort®Communicating) outdoor units (sensor is furnished with iComfort®Communicating
outdoor units). Allows the thermostat to display outdoor temperature. Required in dual-fuel and EDA applications.
2 Cleanable polyurethane frame type lter.
NOTE - Termination Kits (44W92, 44W93, 30G28, 51W12, 81J20) and Crawl Space Vent Drain Kit (15Z70) are certied to ULC S636 standard for use in Canada only.

Page 4
BLOWER DATA
SLP99UH070XV36B BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections Heating Input Range and Blower Volume - CFM
35% 40% 50% 60% 70% 80% 90% 100%
Increase (+15%) Heat CFM 489 538 636 735 833 931 1030 1128
Increase (+7.5%) Heat CFM 450 496 588 680 772 864 956 1048
Default Heat CFM 410 453 539 624 710 796 881 967
Decrease (-7.5% ) Heat CFM 380 419 498 578 657 736 815 895
Decrease (-15% ) Heat CFM 349 385 458 531 604 676 749 822
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Blower Speed Selections
First Stage Cool Speed - cfm Second Stage Cool Speed - cfm
Low Medium-
Low
Medium
High
High
(Default)
Low Medium-
Low
Medium
High
High
(Default)
Increase (+10%) Cool CFM 600 740 840 970 860 1060 1215 1365
Default Cool CFM 555 665 770 855 810 960 1130 1265
Decrease (-10%) Cool CFM 500 600 680 790 705 840 1005 1140
The e󰀨ect of static pressure is included in air volumes shown.
The following control congurations are available. See Installation Instructions for details and DIP switch settings.
Heat Modes Available (Heating Blower Performance Table):
Single stage thermostat:
- 35%, 70%, 100% input (three-stage) with time delays in-between.
Two-stage thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts ring rate based on rst- and second-stage cycle times.
- W1 demand at 70% input, W2 demand at 100% input. No delay between stages.
Cool Mode Available (Cooling Blower Performance table):
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan speeds are approximately 28% and 38% (DIP switch selectable) of the same second-stage COOL speed position.
minimum 250 cfm.
Lennox iHarmony®Zoning System Applications - Minimum blower speed is 250 cfm.

Page 5
SLP99UH070XV36B BLOWER PERFORMANCE (less lter)
SINGLE SIDE RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections Heating Input Range and Blower Volume - CFM
35% 40% 50% 60% 70% 80% 90% 100%
Increase (+15%) Heat CFM 484 531 625 718 812 906 999 1093
Increase (+7.5%) Heat CFM 446 490 579 667 756 845 933 1022
Default Heat CFM 407 449 533 616 700 784 867 951
Decrease (-7.5% ) Heat CFM 377 413 487 561 635 709 783 857
Decrease (-15% ) Heat CFM 346 378 442 506 571 635 699 763
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Blower Speed Selections
First Stage Cool Speed - cfm Second Stage Cool Speed - cfm
Low Medium-
Low
Medium
High
High
(Default)
Low Medium-
Low
Medium
High
High
(Default)
Increase (+10%) Cool CFM 590 705 805 955 840 1050 1205 1355
Default Cool CFM 540 640 725 820 750 945 1130 1230
Decrease (-10%) Cool CFM 500 580 665 720 685 805 990 1110
The e󰀨ect of static pressure is included in air volumes shown.
The following control congurations are available. See Installation Instructions for details and DIP switch settings.
Heat Modes Available (Heating Blower Performance Table):
Single stage thermostat:
- 35%, 70%, 100% input (three-stage) with time delays in-between.
Two-stage thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts ring rate based on rst- and second-stage cycle times.
- W1 demand at 70% input, W2 demand at 100% input. No delay between stages.
Cool Mode Available (Cooling Blower Performance table):
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan speeds are approximately 28% and 38% (DIP switch selectable) of the same second-stage COOL speed position.
minimum 250 cfm.
Lennox iHarmony®Zoning System Applications - Minimum blower speed is 250 cfm.

Page 6
BLOWER DATA
SLP99UH070XV36B BLOWER PERFORMANCE (less lter)
SINGLE SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections Heating Input Range and Blower Volume - CFM
35% 40% 50% 60% 70% 80% 90% 100%
Increase (+15%) Heat CFM 471 519 614 709 805 900 996 1091
Increase (+7.5%) Heat CFM 435 480 570 660 751 841 931 1021
Default Heat CFM 399 441 526 611 696 781 866 951
Decrease (-7.5% ) Heat CFM 369 408 486 564 643 721 799 877
Decrease (-15% ) Heat CFM 339 375 446 517 589 660 732 803
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Blower Speed Selections
First Stage Cool Speed - cfm Second Stage Cool Speed - cfm
Low Medium-
Low
Medium
High
High
(Default)
Low Medium-
Low
Medium
High
High
(Default)
Increase (+10%) Cool CFM 595 715 815 950 855 1045 1205 1350
Default Cool CFM 520 655 755 840 790 945 1090 1255
Decrease (-10%) Cool CFM 490 595 670 745 720 845 985 1130
The e󰀨ect of static pressure is included in air volumes shown.
The following control congurations are available. See Installation Instructions for details and DIP switch settings.
Heat Modes Available (Heating Blower Performance Table):
Single stage thermostat:
- 35%, 70%, 100% input (three-stage) with time delays in-between.
Two-stage thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts ring rate based on rst- and second-stage cycle times.
- W1 demand at 70% input, W2 demand at 100% input. No delay between stages.
Cool Mode Available (Cooling Blower Performance table):
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan speeds are approximately 28% and 38% (DIP switch selectable) of the same second-stage COOL speed position.
minimum 250 cfm.
Lennox iHarmony®Zoning System Applications - Minimum blower speed is 250 cfm.

Page 7
BLOWER DATA
SLP99UH090XV36C BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections Heating Input Range and Blower Volume - CFM
35% 40% 50% 60% 70% 80% 90% 100%
Increase (+15%) Heat CFM 687 734 827 921 1014 1108 1201 1295
Increase (+7.5%) Heat CFM 654 697 782 867 953 1038 1123 1209
Default Heat CFM 621 660 737 814 891 968 1045 1122
Decrease (-7.5% ) Heat CFM 581 616 687 757 828 899 970 1041
Decrease (-15% ) Heat CFM 540 572 637 701 766 830 895 959
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Blower Speed Selections
First Stage Cool Speed - cfm Second Stage Cool Speed - cfm
Low Medium-
Low
Medium
High
High
(Default)
Low Medium-
Low
Medium
High
High
(Default)
Increase (+10%) Cool CFM 625 710 830 950 875 1040 1210 1360
Default Cool CFM 565 670 760 860 800 945 1100 1240
Decrease (-10%) Cool CFM 520 610 685 785 720 840 970 1115
The e󰀨ect of static pressure is included in air volumes shown.
The following control congurations are available. See Installation Instructions for details and DIP switch settings.
Heat Modes Available (Heating Blower Performance Table):
Single stage thermostat:
- 35%, 70%, 100% input (three-stage) with time delays in-between.
Two-stage thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts ring rate based on rst- and second-stage cycle times.
- W1 demand at 70% input, W2 demand at 100% input. No delay between stages.
Cool Mode Available (Cooling Blower Performance table):
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan speeds are approximately 28% and 38% (DIP switch selectable) of the same second-stage COOL speed position.
minimum 250 cfm.
Lennox iHarmony®Zoning System Applications - Minimum blower speed is 250 cfm.

Page 8
BLOWER DATA
SLP99UH090XV36C BLOWER PERFORMANCE (less lter)
SINGLE SIDE RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections Heating Input Range and Blower Volume - CFM
35% 40% 50% 60% 70% 80% 90% 100%
Increase (+15%) Heat CFM 657 702 792 881 971 1061 1150 1240
Increase (+7.5%) Heat CFM 631 673 757 841 926 1010 1094 1178
Default Heat CFM 605 644 723 802 880 959 1037 1116
Decrease (-7.5% ) Heat CFM 574 608 676 745 814 882 951 1020
Decrease (-15% ) Heat CFM 542 571 630 689 747 806 864 923
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Blower Speed Selections
First Stage Cool Speed - cfm Second Stage Cool Speed - cfm
Low Medium-
Low
Medium
High
High
(Default)
Low Medium-
Low
Medium
High
High
(Default)
Increase (+10%) Cool CFM 610 705 795 920 840 1015 1165 1300
Default Cool CFM 560 640 715 810 770 910 1050 1190
Decrease (-10%) Cool CFM 525 605 665 725 695 795 945 1110
The e󰀨ect of static pressure is included in air volumes shown.
The following control congurations are available. See Installation Instructions for details and DIP switch settings.
Heat Modes Available (Heating Blower Performance Table):
Single stage thermostat:
- 35%, 70%, 100% input (three-stage) with time delays in-between.
Two-stage thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts ring rate based on rst- and second-stage cycle times.
- W1 demand at 70% input, W2 demand at 100% input. No delay between stages.
Cool Mode Available (Cooling Blower Performance table):
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan speeds are approximately 28% and 38% (DIP switch selectable) of the same second-stage COOL speed position.
minimum 250 cfm.
Lennox iHarmony®Zoning System Applications - Minimum blower speed is 250 cfm.

Page 9
BLOWER DATA
SLP99UH090XV36C BLOWER PERFORMANCE (less lter)
SINGLE SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections Heating Input Range and Blower Volume - CFM
35% 40% 50% 60% 70% 80% 90% 100%
Increase (+15%) Heat CFM 677 721 810 899 988 1076 1165 1254
Increase (+7.5%) Heat CFM 639 679 760 842 923 1004 1085 1167
Default Heat CFM 600 637 711 784 858 932 1005 1079
Decrease (-7.5% ) Heat CFM 573 606 673 740 806 873 939 1006
Decrease (-15% ) Heat CFM 546 576 635 695 754 814 873 933
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Blower Speed Selections
First Stage Cool Speed - cfm Second Stage Cool Speed - cfm
Low Medium-
Low
Medium
High
High
(Default)
Low Medium-
Low
Medium
High
High
(Default)
Increase (+10%) Cool CFM 605 715 810 930 850 995 1165 1305
Default Cool CFM 570 660 735 820 775 905 1050 1205
Decrease (-10%) Cool CFM 530 600 670 725 710 800 945 1070
The e󰀨ect of static pressure is included in air volumes shown.
The following control congurations are available. See Installation Instructions for details and DIP switch settings.
Heat Modes Available (Heating Blower Performance Table):
Single stage thermostat:
- 35%, 70%, 100% input (three-stage) with time delays in-between.
Two-stage thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts ring rate based on rst- and second-stage cycle times.
- W1 demand at 70% input, W2 demand at 100% input. No delay between stages.
Cool Mode Available (Cooling Blower Performance table):
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan speeds are approximately 28% and 38% (DIP switch selectable) of the same second-stage COOL speed position.
minimum 250 cfm.
Lennox iHarmony®Zoning System Applications - Minimum blower speed is 250 cfm.

Page 10
BLOWER DATA
SLP99UH090XV48C BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections Heating Input Range and Blower Volume - CFM
35% 40% 50% 60% 70% 80% 90% 100%
Increase (+15%) Heat CFM 769 835 968 1101 1234 1367 1500 1633
Increase (+7.5%) Heat CFM 713 776 902 1028 1155 1281 1407 1534
Default Heat CFM 656 716 836 955 1075 1195 1314 1434
Decrease (-7.5% ) Heat CFM 595 652 767 882 997 1112 1227 1342
Decrease (-15% ) Heat CFM 534 589 699 809 919 1029 1139 1249
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Blower Speed Selections
First Stage Cool Speed - cfm Second Stage Cool Speed - cfm
Low Medium-
Low
Medium
High
High
(Default)
Low Medium-
Low
Medium
High
High
(Default)
Increase (+10%) Cool CFM 840 1005 1155 1315 1165 1375 1580 1770
Default Cool CFM 780 915 1045 1190 1075 1265 1440 1645
Decrease (-10%) Cool CFM 690 835 955 1070 935 1145 1320 1465
The e󰀨ect of static pressure is included in air volumes shown.
The following control congurations are available. See Installation Instructions for details and DIP switch settings.
Heat Modes Available (Heating Blower Performance Table):
Single stage thermostat:
- 35%, 70%, 100% input (three-stage) with time delays in-between.
Two-stage thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts ring rate based on rst- and second-stage cycle times.
- W1 demand at 70% input, W2 demand at 100% input. No delay between stages.
Cool Mode Available (Cooling Blower Performance table):
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan speeds are approximately 28% and 38% (DIP switch selectable) of the same second-stage COOL speed position.
minimum 380 cfm.
Lennox iHarmony®Zoning System Applications - Minimum blower speed is 380 cfm.