COZY HEDV404 Installation And Operating Instructions Manual page 13

@F0
THERMOSTAT
CALLS FOR
HEAT
SEQUENCE OF OPERATION - HEDV403/4
@FX
Th_lmostat
is satisfied
F10 Sec t 15 sec F20 sec F50 sec FX sec tX+15 sec FX÷120 sec
NO
STEP
l)
2}
3}
4)
5}
6)
7}
8)
#
Thermostat calls for heat.
Combustion fan turns on.
Pressure switch closes.
Power to Ignitor.
Ignitor warm up period.
Gas flow to burner.
Burner ignition proven.
Circulating blower on.
NOTE: If there is a mal-
function in any of the
above steps, the sequence
will stop at that point and
STEP #
8) Continued...
return to Step 2. If after 3 attempts
malfunction still occurs, furnace will
go into lockout mode for one hour.
This one hour mode can be bypassed
by resetting thermostat.
9) Thermostat satisfied.
10) Gas valve closes.
11) Combustion fan off.
12) Blower off.
HEATER NOW IN STAND-BY MODE.
Page 13