YORK YLAA — Low Ambient Temperature

The panel prints the message Low Ambient Temperature; this is the only wording the manuals give for it. In the YLAA Fault and Inhibit Codes table the entry reads: code 2, type Unit Fault, description Low Ambient Temperature, with Auto in the table's AUTO, 1X, 3X column. The Native BACnet, Modbus, and N2 communications data map carries the same name and reports it through the Sys 1 / Sys 2 Fault Code points, where the name appears in the point's value list alongside No Abnormal Condition, No Fault Code, Unit Switch OFF and System Switch OFF.

This code is the unit's low ambient temperature cutout condition. The control carries a Low Ambient Temperature Cutout setting, and the data the panel can display includes both the outdoor air temperature and the low ambient temperature cutout setting, so the ambient condition behind the message can be read directly at the panel. The fault table types the entry as a Unit Fault and marks it Auto in its AUTO, 1X, 3X column; the table attaches no component failure and no corrective action to this entry. Read over the data map, the value Low Ambient Temperature distinguishes this condition from No Abnormal Condition, the switch-off states and the other enumerated values of the Sys 1 / Sys 2 Fault Code points.

1. Read the outdoor air temperature on the panel display; the manual lists it among the data the control can show.
2. Read the low ambient temperature cutout setting on the same display; the manual lists it alongside the outdoor air temperature.
3. Compare the two readings at the panel: they are the ambient condition and the threshold the Low Ambient Temperature message refers to.

• The Native BACnet, Modbus, and N2 data map lists the setting as a point described as Low Ambient Temperature Cutout, under the identifiers AI36, 549 and ADF 43, scaled ×10, with °F and °C units.
• The panel's displayable data includes the low ambient temperature cutout setting and the outdoor air temperature, so both values can be checked without opening the data map.

The fault table marks code 2 with Auto in its AUTO, 1X, 3X column; the column header refers the reader to the table's legend for the meaning of the classes. The manuals print no separate manual reset procedure for this message, so the Auto classification is the only reset information given for it.