Two- Stage Multi Position Furnace
Service Manual
21
440 08 2002 02
24 VAC signals applied to W1 and W2 terminals of EFT control.
·
Same light--off routine as described for the signal stage thermostat operation except that at the end of the selected Heat Fan On Delay,
the inducer remains on high fire, the high fire solenoid remains energized and the High Heat fan speed energizes.
NOTE5)The EFT control responds without delay to the presence or loss of W2 (with W1 constant). W1 & W2 results in high
inducer, high fire and High Heat fan speed. W1 only results in low inducer, low fire and Low Heat fan speed.
Heating Request with Gas Supply Line Shut Off:
24 VAC signals applied to W1 terminal of EFT control.
·
Inducer motor turns on at high speed.
·
The high fire solenoid energizes.
·
Following a 3 second prepurge delay, the pilot valve opens and the ignitor begins to warm up.
·
The ignitor glows red--hot for 30 seconds, then turns off.
·
The igniter stays off for 25 seconds, then begins to warm--up again.
·
The igniter glows red--hot for 30 seconds, then turns off.
·
The pilot valve closes 3 seconds after the igniter de--energizes.
·
The inducer de--energizes 5 seconds after the pilot valve closes.
·
The SmartValve proceeds to soft lockout and flashes error code 6.
·
The control exits soft lockout after 5 minutes and begins another ignition sequence.
Gas Valve Diagnostic Codes (See Figure 4)
OFF
=
Control not powered
Heartbeat
=
Normal Operation (Standby or call for heat)
1 Flash
=
Not used
2 Flashes
=
Low Pressure switch closed when should be open
3 Flashes
=
Low Pressure switch circuit was still sensed as open 30 seconds after the inducer was energized. System
is in 5 minute delay mode, with inducer off. After 5--minute delay, a new ignition sequence will be initiated.
(Note: SV9541Q On/Off switch in off position during a call for heat will generate this diagnostic code)
4 Flashes
=
Limit switch string open
5 Flashes
=
Flame sensed out of sequence -- Flame signal still present.
6 F 1 Note 1 =
Soft Lockout --Maximum retry count exceeded (failed to light within 4 trials for ignition)
6 F 2 Notes 1,2
=
Soft Lockout --Maximum recycle count exceeded -- Last failure was Flame Sense Lost
During Run, Cycling Pressure Switch or Blocked Condensate.
6 F 3 Notes 1,2
=
Soft Lockout --Maximum recycle count exceeded -- Last failure was Airflow Proving Circuit
Opened During Run
6 F 4 Notes 1,2
=
Soft Lockout --Maximum recycle count exceeded -- Last failure was Limit Circuit Opened
During Run
7 Flashes
=
Soft Lockout Due to Limit Trips Taking Longer than 2 minutes to Reset; Auto Reset After 1 Hour if Call
for Heat Still Present. Reset by Cycling Call for Heat at Any Time.
8 Flashes
=
High Pressure Switch closed when sould be open.
9 Flashes
=
High Pressure Switch open when sould be closed.
NOTE 1: The 6 + X designation indicates a combination of flash codes: 6 flashes shows the control is in soft lockout, followed
by X flashes to indicate the reason the control went into soft lockout. When the 6+ X code is flashing, the SV9541 will attempt
a new ignition sequence after a five minute delay period, if the call for heat is still present. Reset of the thermostat will initiate
a new ignition sequence immediately.
NOTE 2: Any combination of 5 ‘abnormal’ events during a single call for heat will result in soft lockout. An ‘abnormal’ event
is a Flame Sense Failure During Run, Airflow Proving Circuit Open During Run, or Limit Circuit Open During Run. The flash
code will indicate which was the last ‘abnormal’ event that put the system into the soft lockout state based on the table above.
