Honeywell ST9141A1002 - Manual (Page 5)

5 69-0780
Action System Response
Primary limit switch string closes. • Circulating fan turns off after the selected heat fan off delay timing.
• LED stops flashing.
• Normal operation resumes.
Primary limit switch string is open • Combustion air blower, circulating fan and ignition system are de-energized.
for more than 150 seconds (on each • Control goes into lockout mode.
of three consecutive cycles). • LED flashes four times.
• Control remains in lockout until 24V power is removed and reapplied (control
is reset).
• LED stops flashing.
• Normal operation resumes.
Burner limit opens. • Thermostat and ignition system are de-energized and gas valve closes.
• Combustion air blower and circulating fan heat speed are energized.
• LED flashes once.
Burner limit closes. • Combustion air blower remains energized for postpurge timing.
• The circulating fan remains energized for the selected delay off timing.
• LED stops flashing.
• Normal operation resumes.
Electronic air cleaner is connected. • Electronic air cleaner is energized when the circulating fan heat or cool speed
(Connector to 120 Vac electronic is energized.
air cleaner.)
Humidity control is connected. • Humidifier is energized when combustion air blower is energized.
(Connector to 120 Vac humidifier.)
ST9141A1002 Operating Sequence (Continued)