151B0801 R5 3/28/2006
21
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. Electronic fan timer begins heat “fan off” delay sequence.
b.
Circulating fan turns off after the selected heat “fan off” timing.
c.
Electronic fan timer re-closes oil primary control. (T – 3/T connections
for Beckett R7184).
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; electronic fan timer 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
electronic fan timer 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.
