47
Rev. 2
SYSTEM OPERATION
HEATING TIMING CHART FOR WHITE-RODGERS 50A50 AND HEATCRAFT HSI 1-1A OR HSI-2
INTEGRATED IGNITION CONTROL OPERATION
SEQUENCE OF OPERATION
(Models with White-Rodgers 50A50 or Heatcraft HSI 1-
1A, HSI-2 Integrated Ignition Control)
NORMAL SEQUENCE OF OPERATION
1. Thermostat calls for heat.
2. The induced draft blower is energized, and the pressure
switch contacts close.
3. The ignitor is energized and is allowed to preheat for 17
seconds.
4. The gas valve is energized, delivering gas to the burners
and starting combustion.
5. The control checks for a signal from the flame sensor
within seven seconds after the gas valve is energized.
Gas will continue to flow only if a signal is present.
6. The control waits 30 seconds and turns on the air circu-
lation blower to the speed that was selected for heating
operation. At this time the optional humidifier and elec-
tronic air cleaner are also energized.
7. The thermostat is satisfied and opens.
8. The control de-energizes the gas valve.
9. After a 15 second delay, the induced draft blower and
optional humidifier are de-energized.
10. The air circulation blower has an adjustable delay-off tim-
ing of 60, 90, 120 or 180 seconds (starting from the time
the gas valve closes). This allows more heat from the
furnace to be transferred to the conditioned space. After
this time has elapsed, the blower will be de-energized.
ON
OFF
OPEN
CLOSED
ON
OFF
ON
OFF
ON
OFF
CLOSED
OPEN
AIR CIRCULATION
BLOWER
GAS VALVE
IGNITOR
PRESSURE SWITCH
INDUCED DRAFT BLOWER
THERMOSTAT
SECONDS 0 17 21 24 54 0 15 90
T
H
ER
M
O
ST
AT O
N
G
A
S VA
LV
E
OPE
N
IG
NI
T
O
R O
F
F
EN
D
O
F
T
R
IA
L
FOR I
G
NI
T
IO
N
GAS
V
A
L
V
E W
O
ULD
C
L
O
S
E
IF
F
L
A
M
E
IS
NOT
P
ROV
EN
A
IR BLOWER O
N
T
H
ER
M
O
ST
AT O
F
F
E
N
D
O
F
PO
ST
P
U
RG
E
A
IR BLOWER O
F
F
Seconds 0 5 0 45
On
Off
On
Off
On
Off
Indoor Fan
Outdoor Fan
And
Compressor
Thermostat
COOLING TIMING CHART FOR WHITE-RODGERS 50A50 AND HEATCRAFT HSI 1-1A OR HSI-2
INTEGRATED IGNITION CONTROL OPERATION
Содержание GCIA045A30
Страница 34: ...BLOWER PERFORMANCE SPECIFICATIONS 34 Rev 2...