St9103 Operating Sequence; Setting Delay Off Switches - Honeywell ST9103A Installation Instructions Manual

S9103A ELECTRONIC FAN TIMER
Action
Thermostat calls for heat.
(W terminal is energized.)
Thermostat ends call for heat.
(W terminal is de-energized.)
Burner fails to light.
Established flame fails.
Thermostat begins call for cool.
(G and Y terminals are energized.)
Thermostat ends call for cool.
(G and Y terminals are de-energized.)
Thermostat begins call for fan.
(G terminal is energized.)
69-0771B
UNUSED
3 1 2 3
4 5
H
MOTOR
U
M
B C C H 6 7
1 2
E
U
O O E
R
A
N
N O A
E C
R T L T
ON ON ON
1 2 1 2 1 2
60 SEC 90 SEC
120 SEC
DELAY OFF SWITCH SETTINGS
Fig. 3. Setting delay off switches.

ST9103 Operating Sequence.

• ST9103A closes oil primary control T-T connections.
• Ignition system and oil primary control start the furnace. Oil flows as long as
oil primary control senses flame.
• Burner motor is energized and heat fan on delay timing begins. When timing
is complete, the circulating fan is energized at heat speed and warm air is
delivered to the controlled space.
• Oil primary control is de-energized, terminating the burner cycle.
• Heat fan off delay timing begins. When timing is complete, the circulating
fan is de-energized.
• ST9103A returns to standby mode (oil primary control and circulating
fan are off).
• Oil primary control locks out within lockout timing (timing depends on oil
primary control).
• Burner motor is de-energized.
• If heat fan has started, it continues through the selected delay off period.
• Burner motor is de-energized and oil primary control goes into recycle mode.
• If selected heat fan off delay is longer than the recycle delay timing, the
heat fan continues to run through the next trial for ignition.
• Circulating fan is energized at cool speed.
• Cooling compressor turns on immediately.
• Circulating fan and cooling compressor turn off immediately.
• Circulating fan is energized immediately at cool speed.
• ST9103A maybe factory-configured to operate heat speed in this mode.
4
X
C
ST9103A
ON
1 2
150 SEC
M5550
System Response