28
A180231
Fig. 32 − Gas Control Valve
A180238
Fig. 33 − Orifice Hole
FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Gas valve outlet pressure tap must be tightened to prevent
gas leak.
!
WARNING
FURNACE OVERHEATING HAZARD
Failure to follow this caution may result in reduced furnace
life.
Recheck temperature rise. It must be within limits specified
on the rating plate. Recommended operation is at the
mid−point of rise range or slightly above.
CAUTION
!
7. Set thermostat heat anticipator.
a. Mechanical thermostat − Set thermostat heat anticipator
to match the amp. draw of the electrical components in
the R−W circuit. Accurate amp. draw readings can be ob-
tained at the wires normally connected to thermostat sub-
base terminals, R and W. The thermostat anticipator
should NOT be in the circuit while measuring current.
(1.) Remove thermostat from subbase or from wall.
(2.) Connect an amp. meter as shown in Fig. 34 across
the R and W subbase terminals or R and W wires at
wall.
(3.) Record amp. draw across terminals when furnace is
in heating and after blower starts.
(4.) Set heat anticipator on thermostat per thermostat in-
structions and install on subbase or wall.
R Y W G
10 TURNS
THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
(ANITICIPATOR, CLOCK, ETC.,
MUST BE OUT OF CIRCUIT.)
HOOK-AROUND
AMMETER
EXAMPLE:
5.0 AMPS ON AMMETER
10 TURNS AROUND JAWS
=
0.5 AMPS FOR THERMOSTAT
ANTICIPATOR SETTING
FROM UNIT 24-V
CONTROL TERMINALS
Fig. 34 − Amp. Draw Check With Ammeter
b. Electronic thermostat: Set cycle rate for 4 cycles per hr.
8. Adjust blower off delay The blower off delay has four (4)
adjustable settings from 90 seconds to 180 seconds. The
blower off delay jumpers are located on the furnace
control board. (See wiring diagram Fig. 38) Position A−90
seconds, B−120 seconds, C−150 seconds, D−180 seconds.
To change the blower off delay setting, move the jumper
from one set of pins on the control to the pins used for the
selected blower off delay. Factory off delay setting is 120
seconds.
9. Cooling On Delay is fixed at 2 seconds for either jumper
selection.
Check Safety Controls
1. Check Main Limit Switch(es)
This control shuts off combustion control system and en-
ergizes air−circulating blower motor, if furnace overheats.
By using this method to check limit control, it can be es-
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