Lennox Furnace: Test or reset the Low GWP refrigerant detection board (Test button)
Test or reset the Low GWP refrigerant detection board (Test button) on a Lennox furnace: A short press in Normal mode simulates a leak response (E164 for about a minute); in Leak Detected or Fault mode it resets the board after the problem is fixed; while initializing it skips the rest of the pre-purge.
Applies to: Lennox ML180UHEK furnaces with Low GWP refrigerant detection control board
How to fix test or reset the low gwp refrigerant detection board (test button): step by step
- To test after installation: restore power and wait for the initializing purge to finish.
- Start a cooling or heating call and press the Test button; the blower should start, the compressor should stop (and the burners on a heat call).
- Press Test again to end the simulated leak.
- After a real leak or fault is resolved, press Test to bring the board back to Normal.
If the unit shows an error code, look it up: Lennox Furnace codes
Models
ML180UH045E36AKML180UH045XE36AKML180UH070E36AKML180UH070E36BKML180UH070XE36AKML180UH070XE36BKML180UH090E48BKML180UH090E60CKML180UH090XE48BKML180UH110E60CKML180UH110XE60CKML180UH135E60DK
Source: Lennox ML180UHEK 100166, Furnace Control Board Low GWP Modes of Operation and LGWP Test Button Functionality (Tables 18-19), printed p.34-35. 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.