Reznor 300000 BTU Furnace User Manual
9.0 Commissioning
and Start-Up
(cont'd)
9.3 Check
installation after
start-up:
Observe burner ame at full re. Natural gas ame should be about 1-1/2" in height
with blue coloring. Propane gas ame should be approximately the same length
with blue coloring. Yellow tipping may appear on propane gas. If yellow extends
beyond 1/2 to 3/4", adjust air shutters. See Paragraph 8.6. If shutter adjustment
will not reduce yellowing, check for gas leaks at the control manifold or orice
tting.
Turn the unit off and on, pausing two minutes between each cycle. Observe
for smooth ignition. On two-stage or modulating burner systems, manipulate
temperature adjustment slowly up and down to see if control is sequencing or
modulating properly. Raising temperature setting drives burner on or to full re.
Using a manometer or slant gauge readable up to 14" w.c., check orice manifold
for operating pressure on full re. Natural gas should be 3.5" w.c. at this point.
Propane should be 10" w.c. at this point. Variations from these pressures are not
recommended, as ignition and efciency performance can be adversely affected
by improper pressure adjustment. See Paragraph 6.2.
Place "Owner's Envelope" containing Limited Warranty Card, this booklet, and
any optional information in an accessible location near the heater. Follow the
instructions on the envelope.
DANGER
The gas burner in this gas-red equipment is designed and equipped to provide safe, controlled
complete combustion. However, if the installation does not permit the burner to receive the proper
supply of combustion air, complete combustion may not occur. The result is incomplete combustion
which produces carbon monoxide, a poisonous gas that can cause death. Safe operation of separated-
combustion, indirect-red gas burning equipment requires a sealed, properly operating vent system
which vents all ue products to the outside atmosphere. FAILURE TO PROVIDE PROPER VENTING
WILL RESULT IN A HEALTH HAZARD WHICH COULD CAUSE SERIOUS PERSONAL INJURY OR DEATH.
Install either the horizontal or vertical combustion air/vent system illustrated in Paragraph 6.3
using the concentric adapter supplied. Always comply with the combustion air requirements in
the installation codes and instructions. Combustion air at the burner should be regulated only
by manufacturer-provided equipment. NEVER RESTRICT OR OTHERWISE ALTER THE SUPPLY
OF COMBUSTION AIR TO ANY HEATER. CHECK THE COMBUSTION AIR/VENT SYSTEM FOR
SOUNDNESS AND FUNCTION; MAINTAIN IT IN PROPER OPERATING CONDITION.
10.0 Maintenance
and Service
10.1 Maintenance
Schedule
Form I-SC, P/N 207696 R12, Page 34
WARNING
If you turn off the power supply, turn off the gas. See Hazard Levels,
page 2.
This unit will operate with a minimum of maintenance. To ensure long life and satisfactory performance, a furnace that is operating under normal conditions should be
inspected every four months. If the furnace is operating in an area where an unusual
amount of dust or soot or other impurities are present in the air, more frequent inspection is recommended.
The following procedures should be carried out at least annually (See Paragraphs
10.2.1-10.2.7 for instructions).
Check the gas valve to ensure that gas ow is being shut off completely.
Clean the heat exchanger both internally and externally.
Check the pilot burner and main burners for scale, dust, or lint accumulation.
Clean as needed.
Check the vent/combustion air system; inspect all joints. Replace any parts that do
not appear sound.
Check the wiring for any damaged wire. Replace damaged wiring. (See Paragraph
7.0 for wiring requirements.)
CAUTION: When cleaning, wearing eye protection is recommended.
NOTE: Use only factory-authorized replacement parts.
10.2 Maintenance
Procedures
CAUTION: DO NOT
bottom out the gas
valve regulator
adjusting screw.
This can result
in unregulated
manifold pressure
causing excess
overre and heat
exchanger failure.
10.2.1 Gas Valve
WARNING
The operating valve is the prime safety shutoff. All gas supply lines
must be free of dirt or scale before connecting to the unit to ensure
positive closure. See Hazard Levels, page 2.
Remove external dirt accumulation and check wiring connections. The combination gas
valve must be checked annually to ensure that the valve is shutting off gas ow completely.
Instructions:
1) Locate the 1/8” FPT INLET pressure tap on the combination valve (FIGURE 34).
2) With the manual valve turned off to prevent ow to the gas valve, connect a
manometer to the 1/8” inlet pressure tap in the valve. NOTE: A manometer (uidlled gauge) with an inches water column scale is recommended.
FIGURE 34 -
Top View of
Gas Valves
Single-
Stage Valve
1/8" INLET
Pressure Tap
Two-Stage
Valve
1/8" INLET
Pressure Tap
1/8” Outlet
Pressure Tap
1/8” Outlet
Pressure
Tap
10.2.2 Vent/
Combustion Air
System
10.2.3 Burner Rack
Removal Instructions
3) With the eld-installed manual valve remaining closed, turn the thermostat up
to re the unit and allow the unit to go through one trial for ignition. Reset the
thermostat to shut the unit off. Observe the manometer for two to three minutes for
an indication of gas pressure. No pressure should be indicated on the manometer.
If the manometer indicates a gas pressure, the eld-installed manual gas valve
must be replaced or repaired before the combination gas valve can be checked.
4) If the manometer does not indicate gas pressure, slowly open the eld-installed
manual gas valve. After the manometer's indicated gas pressure has reached
equilibrium, close the manual shutoff valve. Observe the gas pressure. There
should be no loss of gas pressure on the manometer. If the manometer indicates
a loss of pressure, replace the combination gas valve before placing the heater in
operation.
NOTE: Operational pressure settings and instructions for checking pressure settings
are in Paragraph 6.2.
Check at least once a year. Inspect all joints, seams, and terminal caps. Clean grills
and screens.
Replace any parts that need to be replaced.
1. Turn off the gas supply.
2. Turn off the electric supply.
3. Remove control access side panel.
4. Disconnect the pilot tubing and ame sensor lead.
5. Mark and disconnect electric valve leads.
6. Uncouple the union in the gas supply.
7. Remove sheetmetal screws in the top corners of the burner rack assembly.
8. Pull "drawer-type" burner rack out of the furnace.
To disassemble the burner rack:
1. Remove Carryover System --
Natural Gas - remove the ash carryover system from the "manifold end" of the
burner rack
NOTE: Natural gas burner racks manufactured prior to Series 6 have a lighter tube
carryover system. Break the lighter tube connection at the orice and remove the
supply tubing, the drip shield and the lighter tube.
Form I-SC, P/N 207696 R12, Page 35
10.0 Maintenance
and Service
(cont'd)
10.2 Maintenance
Procedures
(cont'd)
10.2.3 Burner Rack Removal Instructions (cont'd)
Propane - break the lighter tube connection at the regulator and remove the lighter
tube orice supply tubing; remove the retaining screws in the drip shield and the
shield; remove the retaining screws and slide out the lighter tube.
2. Pull main burners horizontally away from injection opening and lift out.
3. Remove manifold bracket screws and remove manifold.
4. Remove the main burner orices.
5. Remove screws and lift out pilot burner.
Follow the instructions in Paragraph 10.2.3 to clean. To re-assemble and replace,
reverse the above procedures being careful not to create any unsafe conditions.
CAUTION: When cleaning, wearing eye protection is recommended.
Cleaning Pilot and Main Burners
In the event the pilot ame is short and/or yellow, check the pilot orice for blockage
caused by lint or dust accumulation. Remove the pilot orice and clean with air pressure. DO NOT REAM THE ORIFICE. Check and clean the aeration slot in the pilot
burner.
Clean the metal sensing probe and the pilot hood with an emery cloth and wipe off the
ceramic insulator. Check the spark gap; spark gap should be maintained to 7/64". After
the pilot is cleaned, blow any dirt away with compressed air.
Clean main burners and burner orices using air pressure. Use an air nozzle to blow
out scale and dust accumulation from the burner ports. Alternately blow through the
burner ports and the venturi. Use a ne wire to dislodge any stubborn particles in the
burner ports. Do not use anything that might change the port size.
Clean the burner rack carryover systems with air pressure.
10.2.4 Spark Ignition
System
FIGURE 35 - Spark Gap
The ignition controller provides the high voltage spark to ignite the pilot service and also
acts as the ame safety device. After ignition of the pilot gas, the controller electronically senses the pilot ame. A separate solid metal probe in the pilot burner assembly
is used to sense the ame. A low voltage DC electrical signal is imposed on the metal
probe which is electrically insulated from ground. When the pilot ame impinges on
the sensing probe, the ame acts as a conduction path to ground. This completes the
DC circuit; the ignition controller responds by energizing the main gas valve. Proper
operation of the electronic spark ignition system requires a minimum ame signal of .2 microamps as measured by a microampmeter.
CAUTION: Due to high voltage on pilot spark wire and pilot electrode,
do not touch when energized. See Hazard Levels, page 2.
If no spark occurs, check the following:
a) Voltage between Terminals TH and 7 should be at least 20 volts and no higher
than 32 volts. Refer to Troubleshooting (Paragraph 10.3) if no voltage is observed.
b) Short to ground in the high tension lead and/or ceramic insulator.
c) Pilot spark gap should be approximately .100". (See FIGURE 35.)
Form I-SC, P/N 207696 R12, Page 36
Top
View
NOTE: When checking for spark with the pilot burner assembly removed from the
burner rack, the pilot assembly must be grounded to the heater for proper spark.
If the above conditions are normal and no spark occurs, replace the ignition control-
ler.
Side
View
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