background image

         

Page 1

©2018 Lennox Industries Inc.

Dallas, Texas, USA

THIS MANUAL MUST BE LEFT WITH THE

HOMEOWNER FOR FUTURE REFERENCE

WARNING

Improper installation, adjustment, alteration, service or
maintenance can cause personal injury, loss of life, or
damage to property.

Installation and service must be performed by a licensed
professional installer (or equivalent) or a service agency.

IMPORTANT

The Clean Air Act of 1990 bans the intentional venting of
refrigerant (CFCs, HCFCs and HFCs) as of July 1, 1992.
Approved methods of recovery, recycling or reclaiming
must be followed. Fines and/or incarceration may be
levied for noncompliance.

INSTALLATION
INSTRUCTIONS

Merit

®

 CBX25UHV (-10) Series

Units

AIR HANDLERS

507616-02 
7/2018 

Shipping and Packing List

Package 1 of 1 contains the following:

1 -

Assembled air handler unit factory-equipped for up-flow or
horizontal air discharge application (includes up-flow and
horizontal drain pans and 

pre-installed air filter

).

Check equipment for shipping damage. If found, immediately
report damage to the last carrier. Check the unit rating plate to
confirm that delivered unit matches order.

General

The Merit

®

 CBX25UHV air handler is designed for indoor

installation only. As shipped, the unit is ready for installation in
either up-flow or horizontal left-hand air discharge applications.
Horizontal drain pan may be repositioned in the field to allow
installation in the horizontal right-hand air discharge position.
Various accessories are listed in the 

CBX25UHV Product

Specification bulletin.

All units are equipped with a factory-installed check/expansion
valve.

Summary of Contents for CBX25UHV-018

Page 1: ...507616 02 7 2018 Shipping and Packing List Package 1 of 1 contains the following 1 Assembled air handler unit factory equipped for up flow or horizontal air discharge application includes up flow and horizontal drain pans and pre installed air filter Check equipment for shipping damage If found immediately report damage to the last carrier Check the unit rating plate to confirm that delivered unit...

Page 2: ...s Up flow inches mm NOTE Unit is shipped configured for horizontal left hand air discharge Unit may be converted to horizontal right hand air discharge by repositioning horizontal drain pan Dimensions remain the same in all configurations ...

Page 3: ...ning Systems latest edition The air handler is shipped from the factory completely assembled This unit is provided with flanges for connecting the supply plenum Do not remove the cabinet knockouts until it has been determined which knockouts will need to be removed for the installation Select the air discharge position which best suits the site conditions Consider required clearances space routing...

Page 4: ... in the desired location and properly slope the unit see page 8 Connect the return and supply air plenums as required using sheet metal screws 4 In applications that do not include a return air plenum install units on a stand that is raised at least 14 above the floor This ensures proper air return HORIZONTAL DRAIN PAN IMPORTANT REMOVE PAN FOR BEST EFFICIENCY AND AIR FLOW UP FLOW DRAIN PAN UP FLOW...

Page 5: ...ge the following field modifications are required 1 Remove and set aside blower and coil access panels 2 Remove brackets securing pans to unit See figure 4 Figure 4 Remove Main Drain Pan Mounting Brackets 3 Remove coil assembly bottom drain pan and horizontal drain pan as one unit from the air handler Figure 5 Remove Coil Assembly Bottom Drain Pan and Horizontal Drain Pan As A Unit 4 Remove the bl...

Page 6: ...that Hold the Coil and Horizontal Drain Pan in Place Repositioning Black Box on Motor Module 018 024 and 030 Units When the horizontal drain pan is moved to the right side of the air handler the black box on the back of the supply fan motor will prevent the insertion of the blower assembly back into the cabinet The black box must be repositioned to overcome this issue Tools and Material Required 1...

Page 7: ...r than the original position Figure 12 Black Box Repositioned on Motor Module 11 Slide the blower assembly into the cabinet to confirm clearance between the horizontal drain pan and the black box Remove the blower assembly and relocate the black box if necessary to achieve clearance Make note of the new position Apply two new strips of double sided tape to the black box and affix it to the module ...

Page 8: ...ater standing in the pan THIS CORNER SHOULD BE 5 8 1 8 HIGHER THAN DRAIN CORNER DRAIN CORNER THIS CORNER SHOULD BE 5 8 1 8 HIGHER THAN DRAIN CORNER Figure 14 Sloping the Unit for Proper Drainage INSTALL CONDENSATE DRAIN The air handler is equipped with NPT condensate drain connections IMPORTANT On some pans the primary and secondary drain holes have knockouts Confirm primary and secondary drains a...

Page 9: ...PE IN HALF AND USE IT TO ROUTE THE MAIN DRAIN Figure 16 Typical Main and Overflow Drain 2 Install properly sized field provided connection fittings and connect primary drain line to the main drain pan connection NOTE When installing drain line connection fittings to the drain pan hand tighten the fitting and use a thread sealant Over tightening the fittings can split connections on the drain pan 3...

Page 10: ...rs have a higher static pressure drop than standard efficiency glass foam filters If the pressure drop is too great system capacity and performance may be reduced The pressure drop may also cause the limit to trip more frequently during the winter and the indoor coil to freeze in the summer result ing in an increase in the number of service calls Before using any filter with this system check the ...

Page 11: ...ntroduction of moisture into a system NOTE When installing refrigerant lines longer than 50 feet see the Lennox Refrigerant Piping Design and Fabrication Guidelines CORP 9351 L9 or contact Lennox Technical Support Product Applications for assistance To obtain the correct information from Lennox be sure to communicate the following information Model and capacity 1 Route the suction and liquid lines...

Page 12: ...TO ALLOW FILTER ACCESSIBILITY NOTE CBX25UHV SERIES UNITS USE NITROGEN OR DRY AIR AS A HOLDING CHARGE IF THERE IS NO PRESSURE WHEN THE RUBBER PLUGS ARE REMOVED CHECK THE COIL FOR LEAKS BEFORE INSTALLING REFER TO INSTRUCTIONS PROVIDED WITH OUTDOOR UNIT FOR LEAK TESTING EVACUATING AND CHARGING PROCEDURES FLOW REGULATED NITROGEN AT 1 TO 2 PSIG THROUGH THE REFRIGERATION GAUGE SET INTO THE VALVE STEM PO...

Page 13: ... through specified low voltage opening Run line voltage wiring only through specified high voltage opening Do not combine voltage in one opening WARNING Electric Shock Hazard Can cause injury or death Foil faced insulation has conductive characteristics sim ilar to metal Be sure there are no electrical connections within a of the insulation If the foil faced insulation comes in contact with electr...

Page 14: ...ical unit wiring as well as wiring of optional field installed electric heat is given in figure 21 Refer to the instructions provided with the electric heat section for proper installation See figure 22 for typical low voltage field wiring connections WARNING USE COPPER CONDUCTORS ONLY 1 Disconnect all power supplies 2 Remove the air handler access panel 3 Route the field supply wires to the air h...

Page 15: ...O 104796 01 12 BLK 12 BLK 1 2 3 4 5 1 2 3 4 5 6 8 9 10 11 12 13 14 15 7 1 2 3 4 5 6 8 9 10 11 12 13 14 15 7 16 Y2 DS O W1 W2 Y1 G 14 RED L2 18 BLUE L2 18 WHITE L2 18 BLACK L2 R CIRCUIT BOARD MOTOR TR BR GRD 18 YEL 18 ORG 18 PRPLE 18 BLUE WHITE 18 GRN 18 RED 18 WHITE 18 BLK 18 RED 18 YEL 18 BLUE 18 RED 18 RED 18 YEL 14 YEL 14 YEL 14 BLK 18 WHITE 18 WHITE 18 WHITE 18 WHITE 18 WHITE 18 WHITE 18 WHITE...

Page 16: ...Page 16 WARNING USE COPPER CONDUCTORS ONLY Figure 22 Low Voltage Connections Variable Speed Motor ...

Page 17: ...er speed needed to meet application CFM requirements JUMPER SETTINGS IMPORTANT Before changing jumper setting make sure the motor has completely stopped Any jumper setting change will not take place while the motor is running Table 2 lists the recommended factory blower speed tap selections for Merit CBX25UHV series units These settings are for nominal tonnage match ups with the Merit CBX25UHV Whe...

Page 18: ...ormance tables With the thermostat set for Continuous Fan and without a call for heating or cooling the Merit CBX25UHV provides 50 of the COOL CFM selected NOTE For two stage heat pumps air handler will operate at 70 of the COOL selection until supplemental electric heat is demanded At that time the air handler will operate at the selected HEAT speed This arrangement provides warmer supply air dur...

Page 19: ... cfm 880 1115 1345 1435 615 770 930 1090 880 1110 1340 1435 NORM 800 1010 1215 1425 555 695 845 990 795 1005 1215 1420 715 905 1095 1275 505 625 755 885 715 905 1090 1280 NOTES The effect of static pressure filter and electric heater resistance is included in the air volumes listed First stage cooling air volume is 70 of COOL second stage speed setting Continuous blower speed is approximately 50 o...

Page 20: ...COOL second stage speed setting Continuous blower speed is approximately 50 of COOL speed setting Lennox Harmony III Zoning System applications minimum blower speed is 450 cfm Table 10 Merit CBX25UHV Thermostat and Single Stage Outdoor Unit Operating Sequence Operating Sequence System Demand System Response System Condition Step Thermostat Demand Relative Humidity Com pressor Air Handler CFM COOL ...

Page 21: ...ndent of a Y1 thermostat demand Normal Operation 1 On On On On Acceptable 24 VAC High 100 Dehumidification mode begins when hu midity is greater than set point Dehumidification Call 2 On On On On Demand 0 VAC High 60 65 70 Dehumidification Call ONLY 1 On On On On Demand 0 VAC High 60 65 70 Thermostat will try to maintain room hu midity setpoint by allowing the room space to maintain a cooler room ...

Page 22: ... indoor units should come on immediately Check the airflow from a register to confirm that the system is moving cooled air Set the thermostat 5ºF higher than the indoor temperature The indoor blower and outdoor unit should cycle off Air handler should cycle off 45 seconds after the outdoor unit shuts off CHECK ELECTRIC HEATER IF USED Set thermostat to call for auxiliary heat approximately 5 F abov...

Page 23: ...must be taped with a similar foil faced tape 1 CUT INSULATION IN X PATTERN 2 APPLY GLUE 3 PRESS GLUED TABS AGAINST CABINET GLUE Make sure there is full coverage of glue on the metal or insulation so there are no areas where air pockets may form which can lead to sweating Figure 24 Repairing Insulation Use of Air Handler During Construction Lennox does not recommend the use of its air handler unit ...

Page 24: ...n Duct Temperature ___________ THERMOSTAT Adjusted and Programmed Return External Static ______ ______ Total External Static ______ ______ 6 Supply Duct Temperature ___________ Temperature Drop ___________ TEMPERATURE RISE Heating Mode Return Duct Temperature __________ Supply Duct Temperature __________ Temperature Rise __________ Operation Explained to Owner 9 Explained Operation of System to Ho...

Page 25: ...___ Total External Static ______ ______ 6 6 Supply Duct Temperature ___________ Temperature Drop ___________ TEMPERATURE RISE Heating Mode Return Duct Temperature __________ Supply Duct Temperature __________ Temperature Rise __________ Operation Explained to Owner 9 Electric Heat Amps 7 Explained Operation of System to Homeowner Technician s Name _______________________Date Start Up Performance C...

Reviews: