NACK Codes

NACK Codes

Frame

Field	Size	Value
REV, SEQ, CNT	4	CNT = 0x0002
Action	1	0x06
Status code	1	See table
CRC	1	Over header + payload

No functional domain or attribute in the NACK payload.

Status codes

Code	Name	Host action
0x00	Reserved	—
0x01	Generic error	Retry 2× with 0.5–1 s delay, then clear
0x02	Reserved	—
0x03	Buffer full / device busy	Retry 2× with 0.5–1 s delay, then clear
0x04	Unsupported protocol revision	Clear transaction
0x05	Unknown action	Clear
0x06	Unknown functional domain	Clear
0x07	Unknown attribute	Clear
0x08	Thermostat cannot accept writes (error/test modes)	Clear
0x09	Timed out waiting for response	Retry 2× with 0.5–1 s delay, then clear
0x0A	Unsupported model	Clear
0x10	Write value out of range	Clear
0x11	Attribute read-only	Clear
0x12	Attribute not writable in current configuration	Clear
0x13	Incorrect write payload size	Clear
0x20	Attribute not readable (write-only)	Clear
0x21	Attribute not available — try later	Clear
0x22	Incorrect read payload size	Clear
0xFF	Extended status (reserved / TBD)	—

Implementation

• Enum NAckError — src/AprilaireClient.ts
• NackResponse + shouldRetry — src/BasePayloadResponse.ts
• Automatic outbound retry queue is backlog P1.3 / #16