York
MA ERR
ProtectMA SENS ERR (JADE LCD example)
JADE two-line LCD: MA / SENS ERR. Mixed-air sensor failed. This one alarms immediately on power-up — others wait the 60-minute setup window.
Walk MA ERR in Diagnose
Sign in for the next measurement
First check
1 Damper position vs command
On York ZF look at the economizer before the compressor. Commanded open? Blade actually open? Linkage off the shaft is a rooftop weekly. Probe mixed air after the damper vs MAT on 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 mixed air after the damper vs MAT on the module.
- Ohm the MA sensor. Open/short or a sensor in the OA stream is this code.
- MAT lying high keeps mechanical cool off. MAT lying low drives the damper shut or trips FREEZING.
Plates that use MA ERR
Same number, other makers
MA ERR on York is not the same code on these plates.