Lennox

Econo

Protect

Economizer FDD

Start here when the hood is the complaint. Title 24 FDD classes: sensor, not-economizing, false-economizing, damper not modulating, excess OA.

Walk Econo 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. Prodigy economizer status. OA thermistor vs a real thermometer.

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

The rest of the walkthrough is Diagnose.

On the plates

Prodigy economizer status. OA thermistor vs a real thermometer.
Read the module in THIS hood (JADE W7220 / W7212 / Reliatel / Prodigy / factory FDD). Type the live LCD string — examples: MA SENS ERR, OA SENS ERR, CO2 SENS ERR, ACT ERROR.
Blade vs command first. Then OA / RA / MAT vs a real thermometer. Then Y1 vs compressor.
Do not add refrigerant because mixed air is cold — that is often the damper.

Plates that use Econo

Same number, other makers

Econo on Lennox is not the same code on these plates.