HVAC Sales Master

Fault Code Lookup

HVAC Sales Master
436 / Inverter Flash 62 — Red LED 6 flashes / Green LED 2 flashes
OD Inverter High Heat-Sink Temperature
This code typically points to
  • Inverter heat sink temperature exceeded limit
  • Loose screws reducing thermal contact between heat sink and inverter control board
Next checks to confirm
  1. Verify high heat-sink temperature condition
  2. Check and tighten screws that hold the heat sink to the inverter control board
  3. Wait 5 minutes for all capacitors to discharge before checking screws
  4. Use outdoor-unit service documentation for further diagnosis
Escalation
Inverter first issues alert code 13 and slows down to cool the heat sink; if temperature remains high, outdoor unit stops compressor and fan as service-soon, anti-short-cycle starts, and if the condition occurs 5 times within 1 hour the system locks out as service urgent
Reset behavior
Service-soon condition automatically clears when the inverter sends an alert-code-clear message; service-urgent condition is cleared by disconnecting power to the outdoor unit and restarting.
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.40
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