HVAC Sales Master

Fault Code Lookup

HVAC Sales Master
434 / Inverter Flash 53 — Red LED 5 flashes / Green LED 3 flashes
OD Inverter Communication Error
This code typically points to
  • Loose or disconnected electrical connections
  • Interruption of main power to inverter
Next checks to confirm
  1. Check for loose or disconnected electrical connections
  2. Verify stable power to the inverter and outdoor section
  3. Use detailed outdoor-unit service documentation if the fault persists
Escalation
If repeated to lockout threshold, outdoor unit locks out and displays alert code 434 as service urgent
Reset behavior
Service-soon condition automatically clears when the system detects the issue no longer exists; if locked out with service-urgent 434, reset by cycling outdoor-unit power off/on first, then cycling indoor 24VAC power to the Lennox outdoor control off/on.
Urgent
Fix now
Need deeper detail?
Retrieve the subcode for this platform:
  1. On thermostat: Menu > Settings > Advanced Settings > Dealer Control Center > Notifications
  2. Review active alarms on homeowner notification screen or in Dealer Control Center > Notifications
  3. For service-app access, press the smart hub commissioning button once
  4. Connect the mobile device to the smart hub when the LED begins blinking green
  5. Use the app as a service tool after system commissioning is already complete (S30 service session auto-logs out after 30 minutes)
Tool required: iComfort Mobile Setup application for service workflow
Source
Lennox Residential Communicating Systems Alert Code Guide 100017c, p.39
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