17
441 01 5001 00
tap, and has a lower contact rating (8 amps) than the heat and cool
taps. When the low speed blower lead is connected to this termi-
nal, this will provide low speed blower operation whenever the oth-
er two speeds (
Heat
or
Cool
) are not energized.
Thoroughly check the system after modification to ensure the
proper operation of the circulating air blower in all modes of opera-
tion.
Separate speed selections for Heat, Cool, and
Continuous Fan
Connect low speed lead from circulating motor to the “
Cont
” termi-
nal at the electronic fan control. The appropriate motor leads
should already be connected to the “
Heat
” and “
Cool
” terminals.
Heating and Continuous Blower Speed the Same
If it is necessary to operate the heating speed and continuous
blower speed using the same blower speed, connect a jumper be-
tween the “
Heat
” and “
Cont
” terminals on the electronic fan con-
trol.
Note
: There should be only
ONE
motor lead going to the “
Heat
”
and “
Cont
” terminals.
10. Furnace Maintenance
CAUTION
It is recommended that the furnace be inspected and
serviced on an annual basis (before the heating sea-
son) by a qualified service technician.
See
“User’s Information Manual”.
11. Sequence of Operation & Diagnostics
The following is the normal operating sequence.
Cooling (Y) Request:
24 VAC signals applied to Y & G terminals of EFT (electronic fan timer) control.
·
Cool motor speed energized after 5 second Cool Fan On Delay time.
Y & G signals removed from EFT.
·
Cool motor speed de--energized after 90 second Cool Fan Off Delay time.
Circulating Fan (G) Request:
24 VAC signals applied to G terminals of EFT control.
·
Heat motor speed energized without delay.
G signal removed from EFT.
·
Heat motor speed de--energized without delay.
NOTE 1) Furnaces with PSC blower motors de--energize the Low Heat fan speed during the heat exchanger warm--up period on a
call for Heating that occurs during a G request.
NOTE 2) Heating or Cooling requests received during a Fan request cause the fan speed to change to the appropriate heat or cool
speed after the selected Fan On Delay time expires. The fan returns to circulating speed after the selected Fan Off Delay time expires
following loss of the Heating or Cooling request.
Heating (W) Request:
24 VAC signals applied to W terminal of EFT control.
·
I
nducer motor turns on at high speed.
·
Following a 3 second prepurge delay, the pilot valve opens and the ignitor begins to warm up.
·
After the pilot lights, the main burners energize and light (burners).
·
Timed from the opening of the main gas valve, the control will delay the selected Heat Fan On Delay time.
W signal removed from EFT.
·
The gas valve de--energizes and the main burners go out.
·
The inducer runs for a 30 second postpurge period.
·
The fan stays at Heat speed.
·
Timed from the gas valve de--energizing, the Heat fan speed
de--energizes after the selected Heat Fan Delay time expires.
Heating Request with Gas Supply Line Shut Off:
24 VAC signals applied to W1 terminal of EFT control.
·
Inducer motor turns on.
·
Following a 3 second prepurge delay, the pilot valve opens and
