Carrier 58PB - Page 14

HEATING ft COOLING
58ED,PB
Horizontal Gas-Fired Furnaces
All forced air furnaces are equipped with a high
temperature limit switch which prevents the furnace
from overheating. If the furnace overheats for any
reason, the high temperature limit opens, breaking the
circuit to the gas valve. The blower motor continues to
run. The main burners cycle on limit until the fault is
corrected.
A WARNING
If overheating occurs, or if the gas supply fails to
shut off, shut off the manual gas valve to the furnace
before shutting off the electrical supply.
The furnace is equipped with either Honeywell S86E or
S86G intermittent pilot control.
S86E control. If the pilot fails to light, the pilot valve
and spark gap remain energized until there is a successful
ignition.
S86G control: If the pilot fails to light, the control
will shut down the system. To initiate a reignition
trial, turn down the thermostat to lowest setting, wait
at least 60 seconds, and then reset thermostat to a setting
above room temperature.
Starting Procedure
STANDING PILOT MODELS
1. Set the manual gas shutoff valve at OFF position.
Wait 5 minutes.
2. Be sure all electrical power to furnace is off.
3 Check all wiring using proper wiring diagram on
inside of blower door.
4. Light the pilot by following instructions on lighting
plate. (Main burners should not light.)
a) Remove burner cover.
b) Turn manual gas shutoff valve to PILOT position.
c) Depress dial, light pilot with a match or taper.
Keep dial depressed until pilot remains lit after
dial is released (approximately 30-45 seconds).
If pilot does not remain lit, repeat operation,
allowing a longer period before releasing dial.
d) Replace burner cover.
5. Adjust pilot flame to envelop the thermocouple a
distance of 3/8 to 1/2 inch. The adjusting screw for
pilot flame is located on main gas control. With
standing pilot, rate is approximately 1000 Btuh.
See Fig. 13.
Fig. 13 — Pilot Thermocouple or Sensor Position
6. With the pilot lit, set thermostat above room
temperature.
7. Turn on power supply to furnace. This energizes
gas valve which should click open. The burners
should not light.
8. Open the manual gas valve on the automatic gas
valve. Burners should light and remain on.
9. Check for leaks in manual valve, gas control valve
and gas connections using soap and water solution.
A CAUTION
Never use an open flame when testing for leaks.
Use soap and water solution.
10. L eave burners on for 15 minutes before making
combustion adjustment
ELECTRONIC IGNITION MODELS
1. Set the manual gas shutoff valve at OFF position.
Wait 5 minutes.
2. Be sure all electrical power to furnace is off
3 Check all wiring using proper wiring diagram on
inside of blower door.
4 Set thermostat above room temperature.
5. Turn on power supply to furnace. This energizes the
pilot valve and spark igniter. The burners should
not light.
6. Turn dial on gas valve to ON position. The pilot
should light. When the sensing probe detects the
presence of pilot flame, the control de-energizes
spark igniter and energizes main gas valve. Main
burners should light and remain on. (If system shuts
down on S86G control, a reignition trial is
necessary.)
7. Check for leaks in manual valve, gas control valve
and gas connections using a soap and water solution.
A CAUTION
Never use an open flame when testing for gas
leaks. Use a soap and water solution.
8 Leave burners on for 15 minutes before making a
combustion adjustment.
Combustion Adjustment
ALL FURNACES — A primary air shutter assembly is
provided on all furnaces. The shutters are factory set for
natural gas furnaces and a closed position for LP gas
furnaces. Readjustment may be required to obtain
optimum setting. Shutters are individual to each burner,
so adjustment of the burner flame must be done one
burner at a time. See Fig. 14.
Loosen the locking screw and close the air shutter.
This should cause the burner flame to glow bright yellow
Open the shutter until the flame turns blue. Lock the
locking screw. See Fig. 15 for proper flame. Repeat this
procedure until all burners are properly adjusted. A
visual check of the main burner and pilot flame should
be made at the beginning of each heating season.
Safety Pilot Check — For Standing Pilot Models
Only. After operating for 15 minutes, turn the valve to
the OFF position. The pilot switch should snap open
between 20 seconds and 3 minutes later. To re-ignite
pilot, follow the nameplate instructions.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Bookll 14 PC101 Catalog No 535-834 PrintedinUSA Form 58ED.PB-1SI Pg 14 6-85 Replaces: 58PB-1 SI
Tab 16a 18a For replacement items use Carrier Specified Parts