Get the most from your Lennox G40UH-36A-070-15 furnace with genuine OEM replacement parts sourced through Repair Clinic. The G40UH-36A-070-15 is a 70,000 BTU upflow 80% AFUE gas furnace in Lennox’s G40UH X series, sized for a 3-ton air handler configuration and designed for B-vent non-condensing installation. Over the service life of the unit, components including the flame sensor, igniter, inducer motor, blower motor, and control board wear and require replacement. Use the Lennox G40UH parts list or G40UH(X) parts diagram to identify your component, then browse the complete Lennox furnace parts catalog to confirm the correct fit.
About the Lennox G40UH-36A-070-15 Furnace
The Lennox G40UH-36A-070-15 is part of the G40UH X series, an 80% AFUE non-condensing upflow furnace line that uses standard metal B-vent exhaust. The -36A suffix indicates the 3-ton blower assembly, the 070 denotes 70,000 BTU input, and the -15 is the revision designator. Blower motor assemblies in the G40UH series are sized per tonnage: the 36A blower is not interchangeable with 30A or 42A configurations even at the same BTU rating, so confirming the full model suffix before ordering a blower motor is essential. The G40UH series differs from the higher-efficiency G26Q3 and G20Q3E Whisper Heat series in cabinet design and blower assembly; those platforms are not cross-substitutable with G40UH parts. For diagnostic help, visit the Lennox furnace repair help section.
Most Replaced Parts on the G40UH-36A-070-15
Lennox G40UH Flame Sensor Shutdown Diagnosis
The Lennox G40UH flame sensor is a ceramic-bodied ionization rod positioned in the burner flame ribbon. Combustion byproducts deposit a thin oxide layer on the rod over time, increasing its electrical resistance until the control board can no longer detect a valid flame signal. The classic symptom is a furnace that ignites, runs for 5 to 10 seconds, then shuts off and lockouts out after three attempts. This is the most searched Lennox G40UH issue for this platform. Browse Lennox furnace flame sensor parts for compatible replacements.
G40UH-36A-070-15 Ignitor Failure and Cold No-Heat Calls
The Lennox G40UH ignitor is a silicon nitride hot surface element that fractures with age, producing erratic or absent glow on a heat call. Because the G40UH-36A-070-15 has no backup ignition method, a failed ignitor results in a complete no-heat condition regardless of whether the gas valve and flame sensor are functioning correctly. The ignitor is one of the most frequently replaced parts on this platform. Always handle the ceramic body only to avoid oil contamination shortening the new ignitor’s service life. Find the correct part at the Lennox furnace igniter page.
Lennox G40UH Inducer Motor Bearing and Draft Failure
The Lennox G40UH inducer motor draws combustion air through the heat exchanger and exhausts it through the B-vent flue. Bearing wear in an aging motor produces a loud squeal or grinding noise during the inducer pre-purge stage, eventually causing the motor to stall. A stalled inducer prevents the pressure switch from closing, locking the furnace before ignition. If the furnace runs the inducer and then stops without advancing to the igniter stage, measure pressure switch operation before condemning the switch itself. Browse Lennox furnace inducer motor parts for the correct replacement.
Lennox G40UH Blower Motor Replacement and Tonnage Matching
The blower motor on the G40UH-36A-070-15 is a PSC motor sized for the 3-ton 36A blower assembly. Weak or absent airflow from supply registers, combined with a furnace that overheats and trips the limit switch repeatedly, points to a failing blower motor rather than a blocked filter. When ordering a Lennox G40UH blower motor replacement, confirm the -36A tonnage designation from the full model number: a blower motor from a 30A or 42A configuration will not fit the 36A assembly. See compatible options at the Lennox furnace blower motor page.
Lennox G40UH Control Board and Sequencing Faults
The Lennox G40UH control board manages the complete heating cycle sequence including inducer timing, igniter warm-up period, gas valve energization, and blower delay on and off. A board that has suffered voltage damage or component failure can produce symptoms at any stage: an inducer that runs indefinitely without advancing, an igniter that never energizes, or a blower that runs continuously after the heat call ends. Record the fault LED pattern before removing the board. Find replacements at the Lennox furnace control board page.
Why Choose Repair Clinic for Lennox G40UH-36A-070-15 Parts
- Genuine Lennox OEM Parts: Every G40UH-36A-070-15 component meets original equipment specifications, ensuring the ignition and airflow systems operate within design parameters. Browse the full Lennox furnace parts catalog for your configuration.
- Tonnage-Matched Blower Components: Our listings include the full model suffix so you confirm the correct 36A blower motor and assembly for the G40UH-36A-070-15 rather than ordering a part sized for a different tonnage configuration.
- Fast Shipping During Heating Season: In-stock parts ship quickly so heating is restored without extended downtime, with order tracking available throughout.
- Step-by-Step Repair Guidance: Pair your replacement part with instructions from the Lennox furnace troubleshooting section to diagnose the root cause before ordering and complete the repair with confidence.
Lennox G40UH-36A-070-15 Furnace Parts FAQ
Why does my Lennox G40UH furnace ignite and shut down after a few seconds?
The most common cause is a dirty or oxidized Lennox G40UH flame sensor that cannot sustain a valid flame signal to the control board. The board interprets the weak signal as a failed ignition attempt and shuts off the gas valve on safety. Cleaning or replacing the sensor resolves this in the majority of cases.
How do I confirm the correct blower motor for a Lennox G40UH blower motor replacement?
Verify the full model number suffix before ordering. The -36A designator in G40UH-36A-070-15 identifies the 3-ton blower assembly. Blower motors are tonnage-specific and cannot be substituted across 30A, 36A, or 42A configurations even within the same G40UH BTU rating.
What is the Lennox G40UH(X) parts list and how is it different from the standard G40UH list?
The G40UH X designation refers to the current-production revision series of the G40UH platform. The G40UH(X) parts list covers revised igniter and control board part numbers introduced in later production runs. When ordering, confirm your unit’s revision suffix against the parts diagram to ensure you receive the correct generation of component.
Can I use parts from a Lennox G26Q3 or G20Q3E on my G40UH-36A-070-15?
No. The G26Q3 and G20Q3E Whisper Heat series use different cabinet dimensions, blower assemblies, and in some cases different control board firmware than the G40UH platform. Parts are not cross-substitutable between these series even when BTU ratings match.
