FieldBench
Lennox codes

Lennox

False econ

Protect

Economizing when it should not

Damper open with OA above changeover. Space hot, high OA bills, or wet coil.

Walk False econ in Diagnose

2 plates — walk the one on the cabinet

First check

1 Damper position vs command

On Lennox LGH look at the economizer before the compressor. Commanded open? Blade actually open? Linkage off the shaft is a rooftop weekly. OA vs changeover setpoint. Sensor lying low (see OA T) is the usual.

Expect: Blade matches the module command. Stuck open = overventilation. Stuck closed = no free cooling.

The rest of the walkthrough is Diagnose.

On the plates

  • OA vs changeover setpoint. Sensor lying low (see OA T) is the usual.
  • Min position cranked to 40% on a small store. DCV failed high.
  • Power-fail default on some actuators is spring-open — they dump OA with 24 V lost.

Plates that use False econ

Same number, other makers

False econ on Lennox is not the same code on these plates.