FieldBench
Lennox codes

Lennox

RA ERR

Protect

RA SENS ERR (JADE LCD example)

JADE LCD: RA / SENS ERR. Return-air thermistor failed. Differential / enthalpy changeover compares OA to RA.

Walk RA ERR 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. Probe RA in the return vs the module.

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

The rest of the walkthrough is Diagnose.

On the plates

  • Probe RA in the return vs the module.
  • A missing RA sensor on a differential setup looks like false economizing.

Plates that use RA ERR

Same number, other makers

RA ERR on Lennox is not the same code on these plates.