Lennox CK40CT Indoor Coils

Residential Product Specifications (EHB)

Product Type: Indoor Coils

Capacity Range: 1.5 to 5 Tons

Coils are furnished with a factory installed R-410A expansion valve. An R-454B expansion valve may be substituted. Refer to page 5 for R-454B Refrigerant Conversion details.

Model Number Identification

The model number follows the format CK40CT-XX-YY, where:

CK40CT: Base model designation indicating an Upflow | Cased | Quantum™ Coil with TXV Furnished, compatible with R-410A / R-454B.
XX: Represents the Nominal Cooling Capacity (Tonnage).
YY: Represents the Cabinet Width Identifier.
Revision Level (e.g., 01): Indicates specific configuration, such as R-410A TXV installed.

Example Breakdown: CK40CT-36A-01

36: Nominal Cooling Capacity (3 tons)
A: Cabinet Width (14-1/2 inches)
01: Revision Level (R-410A TXV installed)

Nominal Cooling Capacity Mapping:

Size Code	Nominal Cooling Capacity
18/24	1.5/2 tons
24	2 tons
30	2.5 tons
30/36	2.5/3 tons
36	3 tons
48	3.5/4 tons
49	4 tons
50/60	4/5 tons
60	5 tons

Cabinet Width Mapping:

Identifier	Cabinet Width
A	14-1/2 in.
B	17-1/2 in.
C	21 in.
D	24-1/2 in.

Furnaces with the same letter designation physically match the indoor coil.

Approvals and Warranty

Approvals

Tested with matching air conditioners and heat pump units in the Lennox Research Laboratory environmental test room in accordance with AHRI Standard 210/240-2023.
AHRI Certified system match-ups and expanded ratings available at www.LennoxPros.com.
Air resistance tests conducted in Lennox Laboratory air test chamber.

Coils can be field configured for use with R-454B refrigerant during initial installation only. Modifications after initial installation are not permitted.

Warranty

All other covered components:
Limited five years in residential installations.
Limited one year in non-residential installations.

Refer to Lennox® Basic Limited Warranty at www.Lennox.com for additional details.

Features

Applications

1.5 to 5 ton nominal sizes.
Lennox designed upflow cased indoor coils are easily installed with most Lennox upflow furnaces.
Factory installed R-410A check/expansion valve.
Coils can be field converted for use with R-454B refrigerant.

Coil Construction (Quantum™ Coil)

Lennox designed and fabricated coil.
Aluminum tubing, hairpins, distributor, and header tubes.
Copper refrigerant sweat connections on both liquid and suction lines for easy brazing.
Ripple-edged aluminum fins for enhanced heat transfer.
Lanced fins maximize fin surface area exposure to the air stream.
Helical grooved tubing provides superior heat transfer.
Twin coil construction assembled in an "A" configuration for large surface area.
High pressure testing ensures leak-proof construction.

Refrigerant Line Connections

Copper refrigerant sweat connections on both liquid and suction lines for easy brazing.
Lines extend outside of the cabinet for ease of connection.
Refer to dimension drawings for locations.

Anti-Microbial Drain Pan

Non-corrosive, UV-resistant polymer drain pan with dual FPT drain connections.
Anti-Microbial additive resists mold and mildew growth on the drain pan, improving indoor air quality and reducing drain line blockage.

R-410A Check and Expansion Valve

For use with R-410A systems.
Wide range valve with Chatleff style fitting.
Factory installed on all models.

R-454B Refrigerant Conversion

Additional components are required for conversion to R-454B Refrigerant:

Refrigerant Detection System (RDS) Coil Sensor Kit
Refrigerant Detection System (RDS) Blower Control Board
R-454B Check and Expansion Valve

Optional Accessories

Refrigerant Detection System (RDS) Coil Sensor Kit

Complies with UL 60335-2-40 approved standard.
Required for all systems using R-454B refrigerant.
Consists of RDS sensor, lineset sleeves, mounting brackets, and A2L labeling.
Ensures safe operation for systems equipped with R-454B refrigerant.
Indoor sensor detects any R-454B refrigerant.

Refrigerant Detection System (RDS) Blower Control Board

Communicating Blower Control Board (Universal): Compatible with any Lennox® communicating furnace or any non-communicating 24-volt furnace.
Non-Communicating Blower Control Board: Compatible with any non-communicating 24-volt furnace.

Standard Features (Related to RDS)

Complies with UL 60335-2-40 approved standard.
Connects to the RDS sensor.
Supports up to two RDS Sensors (factory setting).
Acts as an interface between the indoor unit and thermostat to control the system.
Ensures safe operation for systems equipped with R-454B refrigerant.
Prevents compressor and heating operation if R-454B refrigerant is detected until it is no longer present.
Energizes the blower if R-454B refrigerant is detected to mitigate concentrations in the conditioned space.
Multi-color LED for system status and troubleshooting aid.
Flashing LED codes for system status (Green/Blue) and sensor errors (Red).
Alarm relay can trigger an external alarm if R-454B refrigerant is detected.
Zone relay opens all zone dampers (if part of a zoning system) if R-454B refrigerant is detected.
Disables power to non-communicating thermostats to prevent demand if R-454B refrigerant is detected.
On system start-up, the blower runs for five minutes and all thermostat demands are disabled.
Dimensions (H x W x D): 7-7/16 x 7-7/16 x 2-1/2 inches (189 x 189 x 127 mm).

Refer to Installation Instructions for additional information.

R-454B Check and Expansion Valve

For use with R-454B systems.
Wide range valve with Chatleff style fitting.
Replaces factory-installed TXV, internal to the cabinet.

Cabinet

Pre-painted heavy gauge steel.
Insulated with thick fiberglass insulation.
Flanges provided in outlet for ease of duct connection.
Coil slides out of cabinet for ease of servicing.
Removable panels provide access to the coil.
Refrigerant lines extend outside of the cabinet for easy installation.

Furnace Match-Up

Coils exactly match corresponding furnaces with the same letter designation in the model number.
No adaptor required.
Engaging holes furnished on the cabinet for alignment with the furnace.

Specifications

R-454B Refrigerant Conversion - Order Separately

Description	Order No.
Refrigerant Detection System (RDS) Coil Sensor Kit	26Z69
Refrigerant Detection System (RDS) Blower Control Board	Any Lennox® Communicating Furnace or any Non-Communicating 24V Furnace (Universal)	27A03
	Any Non-Communicating 24V Furnace	27A02

Note: Communicating Blower Control Board and Sensor can be used universally with Lennox® communicating furnaces or any non-communicating 24-volt furnace. Non-Communicating Blower Control Board and Sensor can be used with any non-communicating 24-volt furnace.

Note: Order R-454B Expansion Valve separately.

Optional R-454B TXV Substitution

Note: Additional components are required for R-454B Conversion. See Optional Accessories table.

Size	Order Number
18/24	26Z70
24	26Z70
30	26Z70
30/36	26Z70
36	26Z70
48	26Z71
49	26Z71
50/60	26Z71
60	26Z72

Air Resistance

Size	Air Volume	Total Resistance
Size	cfm	Dry Coil (in. w.g.)	Wet Coil (in. w.g.)
18/24A, 18/24B	400	0.06	0.08
	600	0.11	0.17
	800	0.18	0.25
	1000	0.27	0.39
	1200	0.37	0.52
24A	400	0.05	0.05
	600	0.09	0.10
	800	0.16	0.18
	1000	0.23	0.26
	1200	0.32	0.36
24B	400	0.03	0.04
	600	0.07	0.09
	800	0.11	0.15
	1000	0.17	0.22
	1200	0.23	0.31
30A	600	0.07	0.08
	800	0.12	0.13
	1000	0.18	0.20
	1200	0.26	0.28
	1400	0.34	0.37
30B	600	0.06	0.06
	800	0.09	0.11
	1000	0.13	0.16
	1200	0.19	0.23
	1400	0.25	0.31
30/36A	800	0.13	0.14
	1000	0.19	0.21
	1200	0.27	0.30
	1400	0.34	0.39
	1600	0.45	0.51
30/36B, 30/36C	800	0.08	0.11
	1000	0.13	0.16
	1200	0.17	0.21
	1400	0.22	0.28
	1600	0.29	0.34
36A	800	0.13	0.14
	1000	0.19	0.21
	1200	0.27	0.30
	1400	0.34	0.39
	1600	0.45	0.51
36B	800	0.08	0.11
	1000	0.13	0.16
	1200	0.17	0.21
	1400	0.22	0.28
	1600	0.29	0.34
48B	1000	0.13	0.13
	1200	0.18	0.18
	1400	0.23	0.24
	1600	0.30	0.31
	1800	0.37	0.40
48C	1000	0.07	0.09
	1200	0.10	0.12
	1400	0.13	0.16
	1600	0.16	0.20
	1800	0.20	0.24
49C	1200	0.08	0.12
	1400	0.13	0.17
	1600	0.17	0.22
	1800	0.22	0.28
	2000	0.28	0.35
50/60C	1200	0.13	0.17
	1400	0.18	0.23
	1600	0.23	0.29
	1800	0.28	0.37
	2000	0.34	0.43
60D	1400	0.11	0.15
	1600	0.14	0.18
	1800	0.17	0.21
	2000	0.21	0.27
	2200	0.25	0.32
	2400	0.30	0.37
60C	1400	0.15	0.19
	1600	0.19	0.23
	1800	0.24	0.28
	2000	0.29	0.34
	2200	0.33	0.40
	2400	0.39	0.46

Dimensions

Diagrammatic representations of the coil dimensions are provided. Key dimensions include:

Front View: Shows Liquid Line, Suction Line, RDS Coil Sensor Wiring Inlet, Inlet Opening, Condensate Drains.
Top View: Shows Outlet Opening.
Side View: Shows Air Flow, Inlet Opening.

Detailed measurements (in inches and millimeters) for various models are presented in the table below.

Size	A		B		C		D		E		F		G		H
Size	in.	mm	in.	mm	in.	mm	in.	mm	in.	mm	in.	mm	in.	mm	in.	mm
18/24A	14-1/2	368	16-1/2	419	13	330	13-3/8	340	7-1/4	185	3-5/8	92	2-5/8	66	2-3/8	60
18/24B	17-1/2	445	16-1/2	419	16	406	16-3/8	416	7-1/4	185	3-5/8	92	2-5/8	66	2-3/8	60
30/36A	14-1/2	368	24-1/2	622	13	330	13-3/8	340	13-1/2	343	3-5/8	92	2-5/8	66	2-3/8	60
30/36B	17-1/2	445	24-1/2	622	16	406	16-3/8	416	13-1/2	343	3-5/8	92	2-5/8	66	2-3/8	60
30/36C	21	533	24-1/2	622	19-1/2	495	19-7/8	505	13-1/2	343	3-5/8	92	2-5/8	66	2-3/8	60
36A	14-1/2	368	24-1/2	622	13	330	13-3/8	340	13-1/2	343	3-5/8	92	2-5/8	66	2-3/8	60
36B	17-1/2	445	24-1/2	622	16	406	16-3/8	416	13-1/2	343	3-5/8	92	2-5/8	66	2-3/8	60
24A	14-1/2	368	18-1/2	470	13	330	13-3/8	340	9-3/4	248	3-5/8	92	2-5/8	66	2-3/8	60
24B	17-1/2	445	18-1/2	470	16	406	16-3/8	416	9-3/4	248	3-5/8	92	2-5/8	66	2-3/8	60
30A	14-1/2	368	22-1/2	572	13	330	13-3/8	340	11-1/2	292	3-5/8	92	2-5/8	66	2-3/8	60
30B	17-1/2	445	22-1/2	572	16	406	16-3/8	416	11-1/2	292	3-5/8	92	2-5/8	66	2-3/8	60
48B	17-1/2	445	27-1/2	699	16	406	16-3/8	416	12-1/2	318	3-5/8	92	2-5/8	66	2-3/8	60
48C	21	533	27-1/2	699	19-1/2	495	19-7/8	505	12-1/2	318	3-5/8	92	2-5/8	66	2-3/8	60
50/60C	21	533	27-1/2	699	19-1/2	495	19-7/8	505	12-1/2	318	3-5/8	92	2-5/8	66	2-3/8	60
60D	24-1/2	622	29-1/2	749	23	584	23-3/8	594	10	254	3-5/8	92	2-5/8	66	2-3/8	60
49C	10	254	3-5/8	92	29-1/2	749	2-3/8	60	2-5/8	66
60C	14-1/2	368	3-5/8	92	31-1/2	800	2-3/8	60	2-5/8	66

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