Royal Appliance Air Furnace - Manual (Page 30)

29733 R2 06/01/2003
30
Continued from last page
Mode Action System Response
Limit switch string opens.
(continued)
d. Circulating fan runs as long as limit string stays open.
If there is a call for cooling or fan, the circulating fan switches from
heating to cooling speed.
LIMIT
Limit switch string closes
(with existing call for heat).
a. ST9103 begins heat “fan off” delay sequence.
b. Circulating fan turns off after the selected heat “fan off” timing.
c. ST9103 re-closes oil primary control T - T connections.
d. Oil primary control is energized, initiating burner light-off.
Limit switch string closes
(without existing call for heat).
a. Circulator fan turns off when heat “fan off” delay time is
complete.
b. Normal operation resumes; ST9103 control is in standby mode
awaiting next thermostat command.
FAN
Continuous circulating fan is
connected.
a. Circulating fan is energized when there is no call for heat, cool,
or fan.
b. If fan operation is required by a call for heat, cool, or fan, the
ST9103 switches off the continuous fan speed tap before
energizing the other fan speed.
EAC
Electronic Air Cleaner is
connected.
· Electronic air cleaner (EAC) connections are energized when
the heat or cool speed of the circulator fan is energized. EAC
connections are not energized when the optional continuous
fan terminal is energized.
HUM Humidity control is connected. ·
Humidifier connections are energized when the oil burner
motor is energized.