Restore reliable airflow and system control to your Lennox BCS3M36C00NA1P-1 air handler with genuine OEM replacement parts from Repair Clinic. The BCS3M36C00NA1P-1 is a 3-ton fan coil air handler in Lennox’s BCS series, designed as the indoor unit in a matched split-system installation. The BCS3M36C00NA1P-1 houses the evaporator coil (including the SA11694 coil assembly used in this platform), blower motor, control board, relay assembly, and condensate management components rather than the compressor and outdoor coil. Parts most frequently replaced include the blower motor, run capacitor, control board, and the relay assembly. Use the BCS3M36C00NA1P-1 parts list and browse the full Lennox air handler parts catalog.
BCS3M36C00NA1P-1 in the Lennox BCS Series: Indoor Unit Architecture, SA11694 Coil, and Related Model Designations
The Lennox BCS3M36C00NA1P-1 is a 3-ton fan coil air handler in Lennox’s BCS series. The SA11694 is the evaporator coil assembly part number used in the BCS3M36C00NA1P-1 platform; this coil designation appears in service documentation and should not be confused with the full unit model number. The BCS3M36C00NA1P-1 and the related BCS2M36C00NA1P-1 are similar Lennox BCS series configurations; the BCS2M designation identifies a different blower or control board revision at the same 3-ton output class, and some components including the blower motor may be interchangeable but this must be confirmed against the specific BCS3M36C00NA1P-1 parts list. The RBSC2M36C00NAP-1 is a Rheeem-branded equivalent in the same platform family; the BCE3M36C00NA1P-2 is an adjacent Lennox designation. As the indoor unit, the BCS3M36C00NA1P-1 operates year-round in both heating and cooling modes when paired with a heat pump or operates in cooling mode only when paired with a condensing unit; the blower motor accumulates wear in proportion to total system operating hours. The BCS3M36C00NA1P-1 manual documents blower speed tap settings, drain pan access, and control board terminal identification. For diagnostic guidance, visit the Lennox air handler troubleshooting section.
BCS3M36C00NA1P-1 Component Failures and Indoor Unit Service Sequences
BCS3M36C00NA1P-1 Blower Motor Failure and Capacitor-First Diagnosis
The BCS3M36C00NA1P-1 blower motor circulates conditioned air from the evaporator coil through the duct system. A motor running below rated speed from a degraded run capacitor produces low-airflow symptoms identical to motor failure. Always test the BCS3M36C00NA1P-1 capacitor before condemning the motor; capacitor replacement is significantly less costly than motor replacement and resolves speed-reduction complaints in a substantial proportion of blower motor service calls. Browse Lennox air handler blower motor parts.
Lennox BCS3M36C00NA1P-1 Control Board Sequencing and 24V Input Verification
The BCS3M36C00NA1P-1 control board manages blower speed selection across heating, cooling, and continuous-fan modes and communicates with the matched outdoor unit. Before replacing the control board for any sequencing fault, verify 24-volt AC input voltage at the board terminals using a multimeter; a failed transformer produces board unresponsiveness at significantly lower replacement cost. Browse Lennox air handler control board parts.
BCS3M36C00NA1P-1 Relay Failure and Fan Mode Operation
The BCS3M36C00NA1P-1 relay assembly controls the switching between blower speed modes and heat strip sequencing where applicable. A relay that has failed open prevents blower operation in the affected mode; a relay welded closed prevents the blower from stopping after a mode change. Test each relay coil for continuity and the relay contacts for open-when-energized or closed-when-unenergized conditions before replacing the full relay assembly.
SA11694 Coil Service and Condensate Float Switch on the BCS3M36C00NA1P-1
The SA11694 evaporator coil in the BCS3M36C00NA1P-1 produces condensate during cooling mode that drains through the secondary drain pan to the condensate drain. A restricted drain causes condensate to overflow the drain pan, triggering the float switch that shuts down the system to prevent water damage. If the system shuts down on a hot day with the condensate float switch as the suspected cause, clear the drain line before resetting the float switch; simply resetting the switch without clearing the drain results in immediate repeat shutdown.
Lennox BCS3M36C00NA1P-1 Air Handler Parts at Repair Clinic
- Genuine Lennox OEM Parts for the BCS Series 3-Ton Air Handler: Every BCS3M36C00NA1P-1 part meets Lennox original equipment specifications. Browse the full Lennox air handler parts catalog.
- SA11694 Coil Part Number Context: Our listings clarify the SA11694 as the evaporator coil assembly designation within the BCS3M36C00NA1P-1 platform, distinct from the full unit model number.
- BCS2M and BCS3M Related Model Notes: Our listings identify which BCS3M36C00NA1P-1 components are shared with the BCS2M36C00NA1P-1 and those requiring the BCS3M specific designation.
- Fast Shipping: In-stock BCS3M36C00NA1P-1 parts ship promptly, supported by the Lennox air handler troubleshooting section.
Lennox BCS3M36C00NA1P-1 Air Handler Parts FAQ
What is the SA11694 part number used for in the BCS3M36C00NA1P-1?
SA11694 is the evaporator coil assembly part number for the evaporator coil used in the Lennox BCS3M36C00NA1P-1 air handler. This designation appears in Lennox service documentation for the BCS platform and identifies the coil assembly as a service part; it is not the full unit model number. When ordering coil-related parts, confirm the SA11694 coil designation applies to your specific BCS3M36C00NA1P-1 unit through the parts diagram before ordering.
Are BCS3M36C00NA1P-1 and BCS2M36C00NA1P-1 parts interchangeable?
Some components including the run capacitor and relay assembly may be interchangeable between the BCS3M36C00NA1P-1 and BCS2M36C00NA1P-1 at the same 3-ton output class; the BCS2M designation identifies a different blower or control board revision. Control boards, blower motors, and wiring harnesses should be confirmed against the BCS3M36C00NA1P-1 specific parts list before ordering components from BCS2M listings.
Why should I test the capacitor before replacing the BCS3M36C00NA1P-1 blower motor?
The BCS3M36C00NA1P-1 blower motor requires its run capacitor to develop full torque and rated speed. A degraded capacitor with drifted microfarad values reduces motor torque and speed, producing low-airflow symptoms that are identical to motor bearing wear. Capacitor replacement costs significantly less than motor replacement; testing the capacitor first and replacing it if out of specification resolves low-airflow complaints without motor replacement in a substantial proportion of cases.
What causes the BCS3M36C00NA1P-1 to shut down on hot days?
Unexplained shutdown of the BCS3M36C00NA1P-1 on hot days is most commonly caused by a condensate float switch trip from a restricted drain line. During high-humidity cooling operation the SA11694 evaporator coil produces significant condensate; a blocked drain line fills the secondary drain pan and triggers the float switch to shut down the system to prevent water damage. Clear the drain line completely before resetting the float switch to prevent immediate repeat shutdown.
