Fault Code Lookup

HVAC Sales Master
2 flashes
Pressure switch open
This code typically points to
  • Vent restriction
  • Inducer issue
  • Pressure hose issue

Next checks to confirm
  1. Verify inducer operation
  2. Inspect venting and pressure tubing
  3. Verify switch closure under normal draft

Escalation
If draft proves correct and switch still stays open, switch or control issue is more likely.
Reset behavior
Clears when switch proves correctly.
Urgent
Fix now
Source
MG1 installation manual