Lennox Furnace: Indoor blower does not run – Lennox ML180UHE
Indoor blower does not run - Lennox ML180UHE on a Lennox furnace: Constant-torque ECM blower motor check on the ML180UHEK. The motor needs 120 VAC power on J48 and 24 VAC (12-33 VAC) on one speed tap of J49.
Applies to: ML180UHEK
Common causes of indoor blower does not run - lennox ml180uhe
- No 120 V at the motor
- No 24 V on the active speed tap
- Harness fault
- Failed motor or motor module
- Wheel loose or off-center
How to fix indoor blower does not run - lennox ml180uhe: step by step
- WARNING: Shut off power before unplugging J48/J49.
- Test 1: power on, check 120 VAC across L and N (or 7A and 9A) of J48. If missing, check 120 V across L1 and Neutrals on the control - present means a harness fault, absent means a control/supply problem.
- Test 2: put the thermostat on continuous fan. Look for 24 VAC from J48 C to the J49 fan tap. None there? Look for 24 VAC from 24 COM to the speed tap in use on the control.
- If both voltages are present and the motor does not run correctly, replace the motor (or the module on motors with 4-pin power / 5-pin signal plugs).
- Before fitting a new module test the motor: each pin to the end plate more than 100k ohms; the three motor windings within about 1 ohm of each other. A bad motor will kill a new module.
- Torque module bolts to 22 in-lb; connectors face down to form a drip loop.
- Wheel must be centered in the housing with the set screw on the flat of the shaft.
If the unit shows an error code, look it up: Lennox Furnace codes
Models
Lennox EL195UHNE
EL195UH040NE36BEL195UH060NE36BEL195UH080NE48CEL195UH100NE60C
EL296UHV
EL296UH045XV36BEL296UH070XV36BEL296UH090XV36CEL296UH090XV48CEL296UH090XV60CEL296UH110XV48CEL296UH110XV60CEL296UH135XV60D
Lennox ML180UHE
ML180UH045E36AKML180UH045XE36AKML180UH070E36AKML180UH070E36BKML180UH070XE36AKML180UH070XE36BKML180UH090E48BKML180UH090E60CKML180UH090XE48BKML180UH110E60CKML180UH110XE60CKML180UH135E60DK
Lennox SL280UHV
SL280UH060NV36ASL280UH070V36ASL280UH080NV48BSL280UH080NV60CSL280UH090V36BSL280UH090V48BSL280UH090V60CSL280UH100NV60CSL280UH110V60CSL280UH135V60D
Lennox SL297NV
SL297UH040NV36BSL297UH060NV36BSL297UH080NV48CSL297UH080NV60C
Source: Lennox ML180UHEK Unit Information 100161/100166, Table 6 Integrated Diagnostic Codes, C - Blower Motor, Figures 14-20, p.22-24. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.