Honeywell S8610U Installation Instructions Manual page 14

S8610U UNIVERSAL INTERM ITTENT PILO T MODULE
Step 4: Check pilot and main burner lightoff.
a. Set the thermostat to call for heat.
b. Watch the pilot burner during the ignition sequence to
be sure:
• Ignition spark continues after the pilot is lit.
• Pilot lights and the spark stops, but the main
burner does not light.
• Pilot lights, the spark stops and the main burner
lights, but the system shuts down.
c. If so, verify adequate flame current as follows:
• Turn off the furnace at the circuit breaker or fuse
box.
• Clean the flame rod with an emery cloth.
• Make sure the electrical connections are clean and
tight. Replace the damaged wire with moisture-
resistant No. 18 wire rated for continuous duty up
to 105°C (221° F).
• Check for a cracked ceramic insulator, which can
cause short to ground, and replace the igniter­
sensor or sensor, if necessary.
• A t the gas control, disconnect the main valve wire
from the TH or MV terminal.
• Turn on the power and set the thermostat to call
for heat. The pilot should light but the main burner
remains off because the main valve actuator is
disconnected.
• Check the pilot flame. Make sure it is blue, steady
and envelops 3/8 to 1/2 in. (10 to 13 mm) of the
flame rod. See Fig. 6 for possible flame problems
and the causes.
• If necessary, adjust the pilot flame by turning the
pilot adjustment screw on the gas control
clockwise to decrease or counterclockwise to
increase the pilot flame. Following adjustment,
always replace the pilot adjustment cover screw
and tighten firmly to assure proper gas control
operation.
• Set the thermostat below the room temperature to
end the call for heat.
d. Recheck ignition sequence as follows:
• Reconnect the main valve wire.
• Set the thermostat to call for heat.
• Watch the ignition sequence at the burner.
• If spark continues after the pilot lights, replace the
ignition module.
• If the main burner does not light or if the main
burner lights but the system locks out, check the
module, ground wire, and gas control, as de­
scribed in the Troubleshooting Guide, see Fig. 7.
69-0729—3
APPEARANCE
SMALL BLUE FL AME
ii
LAZY YELLOW FLAME
A
WAVING BLUE FLAME
A
NOISY LIFTING BLOWING FLAME
&
HARD SHARP FLAME
(i
Fig. 6. Examples of unsatisfactory pilot flames.
14
CAUSE
CHECK FOR LACK OF GAS FROM:
• CLOGGED ORIFICE FILTER
• CLOGGED PILOT FILTER
• LOW GAS SUPPLY PRESSURE
• PILOT ADJUSTMENT AT MINIMUM
CHECK FOR LACK OF AIR FROM:
• DIRTY ORIFICE
• DIRTY LINT SCREEN, IF USED
• DIRTY PRIMARY AIR OPENING,
IF THERE IS ONE
• PILOT ADJUSTMENT AT MINIMUM
CHECK FOR:
• EXCESSIVE DRAFT AT PILOT
LOCATION
• RECIRCULATING PRODUCTS
OF COMBUSTION
CHECK FOR:
• HIGH GAS PRESSURE
THIS FLAME IS CHARACTERISTIC
OF MANUFACTURED GAS
CHECK FOR:
• HIGH GAS PRESSURE
• ORIFICE TOO SMALL
M2233A