INSTALLATION AND
International Inc.
4140 WEST VICTORIA STREET • CHICAGO, ILLINOIS 60646 • (773) 604-8700 FAX: (773) 604-4070 • http://www.midco-intl.com
SERVICE INSTRUCTIONS
INCINOMITE MODELS
J81A-3 and J121A-3
Incinerator Gas Burners
The INCINOMITE Models J81A-3 and J121A-3 incinerator gas burners feature continuously monitored electronic flame safety and
spark ignited intermittent proven ignitor (pilot). They are adaptable to either primary or secondary chamber installation.
In the United States, installation must conform with local codes
or, in the absence of local codes, with National Fuel Gas Code
ANSI Z223.1-1992, or latest edition available fromAmerican
National Standard Institute. Further reference should be
made to the recommendation of your fuel supplier.
NOTE: Any additions, changes, or conversions required in order
for the gas utilization equipment to satisfactorily meet the
application needs must be made by a MIDCO distributor (or
other qualified agency) using factory specified and approved
parts.
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
In Canada, installation must conform with local codes or, in the
absence of local codes, with Installation Codes for Gas
Burning Appliances and Equipment, CGA Standard
CAN/CGA 1-B-149.1 or 2. Further reference should be made
to the recommendation of your fuel supplier.
• Do not try to light any appliance.
• Do not touch any electrical switch;
INSTALLER: Inform and demonstrate to
the user the correct operation and
maintenance of this gas utilization
• Immediately call your gas supplier
equipment. Inform the user of the
hazards of storing flammable liquids and
vapors in the vicinity of this gas
• If you cannot reach your gas supplier,
utilization equipment and remove such
hazards. Affix this manual adjacent to
the incinerator burner. CODE
COMPLIANCE IS THE SOLE
RESPONSIBILITY OF THE INSTALLER.
USER: Retain this manual for future reference. If other than routine service or
maintenance as described in this manual is required, contact a qualified service agency.
DO NOT ATTEMPT REPAIRS. An inadvertent service error could result in a dangerous
condition.
SAFETY INFORMATION TERMS: The following terms are used to identify hazards, safety precautions or special notations and
have standard meanings throughout this manual. When you see the safety alert symbol and one of the safety information terms, as
shown below, be aware of the hazard potential.
DANGER: Identifies the most serious hazards which will result in severe personal injury or death.
WARNING: Signifies a hazard that could result in personal injury or death.
CAUTION: Identifies unsafe practices which would result in minor personal injury or product and property damage.
Installation and service must be
performed by a qualified installer, service
agency or the gas supplier.
WARNING: If the information in
these instructions is not followed
exactly, a fire or explosion may result
causing pro p e rty damage, personal
injury or death.
WHAT TO DO IF YOU SMELL GAS
do not use any phone in your
building.
from a neighbor's phone. Follow the
gas supplier's instructions.
call the fire department.
MIDCO
PRINTED IN U.S.A.
797
8470-70
SPECIFICATIONS
1
BURNER AIR DELIVERY(Approximate Air Delivery at Zero Draft)
J81A-3………………………………………....90 SCFM
2
J121A-3………………………………………..180 SCFM
MINIMUM GAS PRESSURE LISTED FOR PURPOSE OF
INPUT ADJUSTMENT
( Take Pressure at Inlet Tap of Main Automatic Va l v e )
N ATURAL………………………………………………..5.5" W . C .
P R O PANE……………………………………………….8.0" W . C .
BURNER FIRING RATE (NAT U R A LOR PROP A N E )
All Ratings Based on 1000 BTU/cu. ft. NATURAL, 2500 BTU/cu. ft. PROPANE at Sea Level
3
M I N I M U M
J81A-3 or J121A-3………………………………… 100 MBH
MAXIMUM (With Combustion Air From Burner Only)
J81A-3
20% Excess Air……………………………450 MBH
0% Excess Air (stoichiometric)…………..540 MBH
J121A-3
20% Excess Air……………………………900 MBH
0% Excess Air……………………………1080 MBH
MAXIMUM (With Combustion Air From Burner Blower and
Additional Air Available in Combustion Chamber.)
NATURALGas 5.5" W.C. or PROPANE Gas
at 11.0" W.C. Gas Pressure at Main Automatic Valve
J81A-3…………………………………………800 MBH
J121A-3……………………………………..1,200 MBH
ELECTRICAL SUPPLY
J81A-3………………………………...120/1/60; 3 a m p s
J121A-3………………………………..120/1/60; 4.5 amps
BURNER ON-OFF CONTROL……………Toggle Switch.
Optional 0 to 6 Hr. Manual Timer
5
FLAME SAFETY…………………...Electronic Flame Safety
with spark ignited ignitor (pilot) and 100% shut-off.
OPTIONAL WEATHERHOOD
5
ADJUSTABLE FIRING ANGLE…………...Mounting Flange
adjustable for horizontal or 10° down firing.
NOTE: Burner components are ULrecognized, CGA listed, CSA
certified and/or AGA design certified, mounted and wired. The
complete burner is fire tested.
1. Standard burners are shipped as NATURAL gas models. A kit is
available for field conversion to PROPANE gas.
2. SCFM = Standard Cubic Feet/Minute.
3. NOTE: Firing rate with combustion air from burner blower only is
based on using standard air at sea level with zero draft over-fire.
Derate burner for altitudes over 2,000 feet by 4% for each 1000
feet above sea level.
4. 100 MBH = 100,000 BTU/Hr.
5. Kit is available for field installation.
PART 1 INSTALLATION
I PRIMARY CHAMBER FUEL INPUT
■ No. 1 Waste: Primarily dry material such as paper, rags
4
and wood. Burner normally required only for light-off.
■ No. 2 Waste:Consisting of approximately equal portions,
by weight of No. 1 and No. 3 waste; 70 lbs. per 100 MBH.
■ No. 3 Waste: Wet material such as garbage; 25lbs. per
100 MBH.
■ No. 4 Waste:Organic materials such as small carcasses
and waste from hospital operating rooms or pathological
laboratories; 13 lbs. per 100 MBH.
NOTE: The burner input required for the secondary
chamber must be determined from the heat required to
maintain the discharge temperature of the flue products as
specified by the EPA for the type of waste involved and the
location of the incinerator.
II INDOOR VENTILATION
Make sure that the incinerator room has suff i c i e n t
ventilation to provide the necessary combustion air for the
burner fuel, the waste material and any other appliance that
would draw its air from the same enclosed area.
WARNING: Under no condition should the access to
outside air be so restricted that the maximum possible
use of combustion air is inhibited. Pay particular
attention to exhaust fans that could draw air from the
area and create a negative pressure in the room.
III INSTALLATION
Install the INCINOMITE burner(s) in location(s) specified by
the incinerator manufacturer. It should be positioned
approximately level with the top of the highest normal load
and fire with or across the draft flow.
FIGURE 1 Typical Installation
-2-
■ If the incinerator is designed only for No. 4 waste, the
level can be lowered to bring the flame to play directly on
the smaller loads characteristic of this type of operation.
The opening through which the burner fires should be of a
diameter only large enough to accommodate the Blast T ube
(41⁄4" diameter x 3" minimum long.) Do not allow the Blast
Tube to protrude into the incineration chamber. If
necessary, build an extension outside of the incinerator wall
to increase wall depth.
■ To change the Mounting Flange to its alternate position,
horizontal or 10° down firing, remove the four (4) screws
that attach it to the burner, rotate the flange 180° and
reinstall the screws.
■ Before mounting the burner, check that the Blast Tube
and Blower Housing are clear of foreign material and that
the Main Gas Port and Nozzle Support is clean and
undamaged.
■ If the incinerator is located outdoors, the burner and all of
its components, except the Main Manual Shut-Off Valve,
must be protected from weather. The MIDCO Accessory
Weatherhood will provide such protection.
CAUTION: If the incinerator is of the down draft
design, make sure that a direct draft vent opening of
approximately 10 square inches has been put through
the top of the drop section(s) to provide for the venting
of any gas leakage. See Figure 1.
IV CHIMNEY, VENT CONNECTOR AND
DRAFT CONTROL
The size and type of material used for the vent connector
and chimney must conform to the recommendations of the
incinerator manufacturer, as well as local and national
codes. This is especially true where high flue gas
temperatures are encountered.
■ When natural draft is used and the chimney height is over
25 feet, a barometric damper of the same size as the vent
connector should be installed. If the chimney is high
enough to make it difficult for the barometric to maintain a
maximum incineration chamber over-fire draft, (0 to minus
0.5” W.C. for Model J81A-3, 0 to minus 1.0” W.C. for Model
J121A-3), a fixed damper should be installed in the vent
connector between the barometric and chimney to restrict
the chimney draft to a point within the controlling capacity
of the barometric. After final setting, the damper should be
permanently fastened into position per ANSI Z223.1-1992
"National Fuel Gas Code", or latest edition available from
American National Standards Institute to prevent
tampering.
■ A suitable Main Gas Pressure Regulator should be
installed as shown in Figures 1 or 3. Choose a regulator(s)
to adjust the available gas pressure to the pressure shown
in SPECIFICATIONS, page 2.
CAUTION: The regulated gas pressures must not
exceed 14:" W.C. or Main Automatic Gas Valve and
Ignitor Regulator will be damaged. If excessive gas
pressure is prevalent, the regulator must be a tight
shut-off type to prevent high pressures from
developing during stand-by. The regulator must have a
minimum flow regulating capacity for the ignitor gas
rate (see Table 4). It is strongly recommended that a
separate smaller regulator be used for ignitor gas,
connecting to the gas line ahead of the Main Gas
Pressure Regulator and downstream of any
intermediate Regulator.
■ For full input, refer to SPECIFICATIONS, page 2, for
minimum gas pressure required. For reduced capacities,
refer to Firing Rate Curves, Table 2 or 3.
CAUTION: If gas supply pressure is below its
specified range during adjustment, an over-fire
condition could result when pressure returns to
normal, particularly if the regulator adjustment screw is
bottomed out. A LWAYS confirm that at least the
minimum rated pressure is being supplied during
regulator adjustments, and NEVER B O T TOM OUT
regulator screw.
■ When selecting the burner supply piping size per Table 1,
the permissible pressure drop must be based on the
pressure available at the inlet to the supply pipe branch line
when all other gas equipment fed by the same source
(NATURALgas meter or PROPANE tank regulator) is firing
at full rate. Also take into account any other INCINOMITE
burners to be attached to the same branch line.
NPT
PIPE
SIZE
3⁄4"
1"
1-1⁄4"
1-1⁄2"
2
TYPE
OF GAS
NATURAL
PROPANE
NATURAL
PROPANE
NATURAL
PROPANE
NATURAL
PROPANE
NATURAL
PROPANE
APPROXIMATE CAPACITY-MBH
LENGTH OF PIPE/FEET
10
20
40
60
100
275
200
130
450
520
820
1050
1200
1200
300
350
550
730
1150
1100
1200
1200
200
245
385
500
790
760
1200
1200
100
165
195
300
400
630
610
960
1150
1200
125
150
235
300
480
460
725
870
1200
V PIPING
The supply piping to the burner should branch off from the
main line as close to the source as possible (NATURAL
gas meter or PROPANE tank regulator). When branching
off from an existing gas line, do not tap off the bottom of a
horizontal section. Use new black pipe and malleable
fittings free from cutting and threading burrs or defects.
■ Use pipe joint compound resistant to liquid petroleum
gases when using either NATURAL or PROPANE gas.
Piping must comply with the local and national codes. If the
burner piping must be rearranged because of space
limitations, be sure to carry out the general configuration
shown in Figure 3.
Capacities shown are for total pressure drop of 0.3"W.C. For
higher permissible pressure drops consult your fuel supplier.
Source: Gas Engineers Handbook-1974
Industrial Press Inc. NY, NY
TABLE 1 Schedule 40 Pipe Capacities in MBH
■ When pressure testing the supply piping, the burner
valve train must be protected. If the test pressure is 0.5
PSIG or less, closing the Main Manual Shut-Off Valve will
suffice.
-3-
CAUTION: If the test pressure is over 0.5 PSIG, the
test must be made without any burner components
connected, including Main and Ignitor Manual Shut-Off
Valves.
WARNING: Explosion hazard.
Do not use oxygen for pressure testing. An explosion
could occur during initial start-up.
VI ELECTRICAL
Installation wiring to the burner must conform to local
codes, or, in their absence in the United States the National
Electric Code ANSI/NFPA No. 70-1990, or latest edition; in
Canada, to CSA standard C22.1, "Canadian Electrical
Code Part 1."
■ Use copper wires and provide disconnect and fuse
protection for each INCINOMITE installation. Refer to
SPECIFICATIONS, page 2, for ampacity. Confirm that the
polarity is correct—hot wire to strip terminal L1, neutral L2
and that the neutral line is not subject to induced low
voltage (check L2 to ground) from other equipment as that
can affect the flame safeguard, causing it to malfunction.
See Flame Safeguard Section X.
CAUTION: In order for the automatic cooling system to
function, power must be maintained to burner strip terminal
L1. Do not install any safety or on-off controls in the circuit
between the fused disconnect switch and strip terminal L1.
Optional remote control devices should be connected in
place of, or in addition to, the switch or timer as indicted in
Figure 2 Wiring Diagram.
NOTE: Optional 0-6 hour Timer may be substituted for the
burner On-Off Switch. Kit is available with full conversion
instructions.
VII INITIAL START UP/ADJUSTMENT
Burners are suitable for use with NATURAL or PROPANE
gas only.
■ If a standard NATURAL gas model is to be used with
P R O PANE gas, a conversion kit is available, which
contains a PROPANE Main Gas Port, a PROPANE Ignitor
Tee Orifice Fitting and a PROPANE label and conversion
instructions.
■ As shipped, the Air Shutter is in the full open position and
the Main Gas Input Adjuster 5 to 6 turns from full closed.
Ignitor regulator is factory set for recommended outlet
pressure of 3.5" W.C. suitable for most applications.
CAUTION: Ignition is automatic. Therefore, make ignitor
or spark observations into incineration chamber only with
Main Manual Shut-Off Valve closed.
1. Check the burner piping and valves for gas leaks by
applying a weak liquid soap solution to unions and
joints with the gas supply on. Leakage will be indicated
by the appearance of soap bubbles. Locate and correct
all gas leaks before proceeding.
WARNING: DO NOT USE OPEN FLAME.
2. Confirm that the main gas Input Adjuster is 5 to 6 turns
from full closed and that the Blower Air Shutter is fully
open.
3. Close the Main Manual Shut-Off Valve and Manual
Ignitor GAs Valve.
4. Purging the air from the gas supply line at this step will
expedite the first light-off.
CAUTION: Purge outside the building. Do not
purge into the incineration chamber.
5. Turn on the Fused Disconnect, Burner Switch or Timer
and press relay reset button. Let motor run long
enough to accomplish four air changes. Note that
motor will continue to run after Flame Safeguard
lockout occurs.
6. Open the incinerator charging door. making sure any
Door Open interlock is temporarily bypassed.
7. Turn on Manual Ignitor Gas Valve only, and press relay
reset button. Trial for Ignitor Ignition: Flame Safeguard
and motor are powered. There will be a delay until
blower reaches operating speed and trips blower
proving switch. When the blower proving switch is
made, the Ignitor Solenoid Valve and Spark Generator
are energized. Ignitor flame should light.
8. If ignitor fails to light during the trial prescribed for
ignition and goes into Flame Safeguard lockout, it is
probably due to air in ignitor gas line. Wait one minute
and press relay reset button for several relight attempts.
If the ignitor fails to light, turn off Manual Ignitor Gas
Valve and repeat from step 5 above. Then, if necessary,
refer to the Trouble Chart to isolate the problem. (Refer
to Section X for trial timings.)
WARNING: Repeated unsuccessful attempts to
light will result in accumulated gases in incineration chamber and chimney. To prevent these
gases from reaching an explosive level,periodically
purge the incineration chamber as described in
Step 5.
9. Observe the ignitor flame. If it is weak, screw in the
Ignitor regulator adjustment to increase the pressure. If
it is excessively rich and large or floating from the igni-
tor tip, back off the regulator adjustment to reduce the
pressure. Set the ignitor to a stable blue flame which
burns firmly within the ignitor tip. Check flame signal
with a DC voltmeter and adjust Ignitor Regulator
slowly for highest steady 2 or more volts DC.
CAUTION: When adjusting the regulator, take note
of the supply pressure. If gas supply pressure is
below its specified range during adjustment, an
over-fire condition could result when pressure
returns to normal, particularly if the regulator
adjustment screw is BOTTOMED OUT. ALWAYS confirm
that at least the minimum rated pressure is being
supplied to the ignitor during regulator adjustments,
and NEVER BOTTOM OUT regulator screw. Operate
air shutter throughout range to confirm Ignitor
stability. Try several relights. Refer to Table 4.
10. Remove the Input Adjuster Cap (see Figure 3) and turn
the Main Gas Input Adjusting Screw until the desired
input rating is reached (refer to Tables 2 or 3). Turning
of adjustment screw counterclockwise increases gas
flow; clockwise reduces gas flow. If Main Flame gas
pressure requires adjustment, refer to Section V Piping.
1 1. Reset the Blower Air Shutter to match the intended
input, i.e.; full open for maximum, closed for minimum
or partially open for midrange. The Blower Air Shutter is
factory set wide open. Adjust as necessary when, with
combustion air available in the incineration chamber, it
is desirable to increase the flame length, or to restrict
the amount of excess air discharged into the incineration chamber when the burner input is below 450 MBH.
-4-
NEUTRAL
120/1/60
HOT
FUSED DISCONNECT
Q7800 BASE FOR
RM7890 FLAME
SAFEGUARD
G
3
4
5
6
7
8
9
10
F
HOT
120/1/60
NEUTRAL
SWITCH OR TIMER
COMPONENT LAYOUT
12
3 2 1
13L2
14
THERMAL
SWITCH
15
16
17
18
19
20
21
22
L
L1
L2
L2
L1
BK
OPTIONAL HI-LO GAS PRESSURE
SWITCH. IF USED, REMOVE
JUMPER 3-4
R/BK
L2 3 4 5 6 7 8 9 10 11
SCHEMATIC
W
Y/BK
10
R/BK
3
SAFETY & OPERATING
CONTROLS
(LINE VOLTAGE)
IF NOT USED JUMPER
10 TO 3
TERMINAL STRIP
SAFETY & OPERATING
CONTROLS
(LINE VOLTAGE)
4 5
3
123
6
Y
J81A-3 MOTOR END SWITCH
J121A-3 BLOWER AIR SWITCH
6
Y/W
8
7
10
8
BL/W BK(W)
9
9
O
F
THERMAL SWITCH
R/W
4
Y/W
BL/W
FLAME ROD
1
2
BK
3
NO
C
5
R
NC
IGNITOR GAS VALVE
SPARK GENERATOR
BLOWER MOTOR
L2
6
W(BK)
SPARK ROD
BRBL BL
MAIN GAS VALVE
OPTIONAL
REDUNDANT VALVE
OPTIONAL VENT
VALVE
FIGURE 2 Wiring Diagram
CAUTION: If a remote switch or timer is installed, remove or turn off the burner switch when using the remote control
12. The actual NATURAL gas firing rate in BTU per hour
can be determined by timing the gas meter. Accurately
time the meter test dial for one revolution, convert to
hourly cubic feet and multiply by the BTU per cubic foot
value of your gas per formula:
3600 x Test Dial Size x BTU Value
No. of Seconds for One Rev. Test Dial
= BTU/Hr.
Then divide by 1,000 for MBH value.
Example: 3600 x 1 x 1000*
=180,000 BTU/ Hr. = 180 MBH
20
*Approximate BTU value.
13. Start and stop the burner several times to check its
operation with the charging door open, and then with
it closed. Remove any temporary Door Open bypasses
installed in Step 6.
14. Test operation of any auxiliary operating and/or limit
controls.
15. Load incinerator and make trial run. Confirm that the
incineration chamber pressure stays within the range of
0 to minus 0.5"W.C. for Model J81A-3 and 0 to minus
1.0” W.C. for Model J121A-3.
16. WARNING: When the incinerator is located
inside a building and a draft control is used, check
that there is no spillage of flue products from the draft
control.
17. To shut off: Turn Burner Switch or Timer off and close
Main Manual Shut -Off Valve
PART 1 SERVICE
WARNING: BE SURE THAT THE MANUAL VALVE AND
BURNER DISCONNECT SWITCH ARE TURNED OFF BEFORE
ANY PARTS ARE REMOVED FOR SERVICE.
VIII IGNITOR AND REGULATOR ASSEMBLY
The Ignitor and Regulator Assembly is removed as a unit.
■ When the ignitor gas pressure is in the proper range (see
Table 4) and the electrodes are adjusted to the dimensions
shown in Figure 5, any ignition problems are usually
caused by lint, dust, corrosion, cracked electrode
insulators, foreign matter in the blast tube or deterioration of
ignitor ports in Retention Plate.
■ Ignitor trouble will be evidenced by failure of main burner
ignition. It may also be indicated by poor or erratic relay
response which cannot be remedied by ignitor gas
adjustment, or it may cause frequent Flame Safeguard
lockout. Check for dirt in the ignitor air and mixture
passageways and check for obstructions in the ignitor
ports. Also check electrode adjustments (see Figure 5).
Replace any severely burned parts.
■ Proper operation of the flame sensor rod can be checked
by measuring the flame signal. With the Flame Safeguard
energized and only the ignitor burning, a good reading
should run steady 2 or more volts DC.
■ When servicing, clean the Ignitor Retention Plate ports
and blow out the internal air and gas passages. Clean the
Electrode Insulators and check them for hairline cracks.
Also check the electrode ends and the Ground Barrier for
serious corrosion or loss of metal. Replace any defective
parts.
■ Make sure that there is no debris in the Blast Tube that
could short out the Spark or Flame Electrode.
■ Clean the Ignitor Gas Orifice in Tee Orifice Fitting (see
Figure 5) and check that the orifice size is correct per Table
4.
MODEL
J81A-3
J121A-3
TYPE
OF
GAS
NATURAL
PROPANE
NATURAL
PROPANE
IGNITOR
ORIFICE
DIAMETER
.052 (#55 Dr.)
.042 (#58 Dr.)
.070 (# 50 Dr.)
.063 (#52 Dr.)
RECOMMENDED
IGNITOR GAS
PRESSURE
3.5 "W.C.
Disconnect the ignitor gas line and electrode wires, remove
the two mounting screws and pull out the assembly.
-6-
TABLE 4 Ignitor Firing Rate
IGNITOR
GAS
RATE
6 MBH
7 MBH
13 MBH
15 MBH
■ Check that the electrode ends are positioned and that the
gap between the end of each electrode and the ground
barrier is spaced per Figure 5.
■ Check that the Ignitor Air Deflector is at the correct angle
(45°). See Figure 4.
■ Inspect the electrode wire insulation for cracks or worn
areas, or any contact with the burner frame. Dampness will
facilitate electrical leakage to ground, which will cause
ignition or flame signal failure.
SPARK TEST—Main Manual Shut-Off Valve must be off.
Place the Ignitor Assembly on top of the burner with the
electrode ends visible and good metal to metal contact
between the Ignitor Mounting Plate and the burner chassis.
■ Connect the high voltage wire to the spark electrode.
Spark should be visible during trial for ignition period and
arc from the electrode end to the Ground Barrier. It should
be audible and visible, though it is rather thin and difficult to
see in bright light.
■ If the spark is not audible or visible it is leaking directly to
ground. Before removing electrodes, check to make sure
voltage is available by positioning the spark wire 1/8" from
the end of the electrode. If necessary, press relay reset
button to recycle ignition sequence.
■ Disconnect Flame Electrode wire and switch the high
voltage wire to the flame electrode and repeat test for
insulator leakage.
CAUTION: Do not indiscriminately change the
ignitor gas orifice size as ignition troubles are rarely
cured in this manner. The ignitor utilizes a premixed
gas/air mixture and, as the air input is relatively fixed,
any adjustment to the gas/air ratio that might be
required for a specific application should be made by
careful adjustment of the ignitor regulator to vary its
outlet gas pressure. Pressure adjustments must be
made when the gas is flowing. If cleaning and electrode
adjustment does not eliminate an ignition problem,
further checks are required. Refer to Trouble Chart.
IX IGNITOR GAS/AIR ADJUSTMENT (J121A-
3 ONLY)
The ignitor assembly as shipped is pre-set during factory
fire-testing and normally needs no adjustment except in
installations where the air shutter is full open. The ignitor
should not be adjusted until it is confirmed that good lightoffs are not possible with ignitor gas pressure adjustments
only as described in Section VIII.
■The Air adjustment screw is located under a plug button
in the Ignitor Block about 1⁄2 inch behind the Ignitor Orifice
(refer to Figure 4). A 5⁄64 (.078) inch hexagon wrench is
required for adjustment. Pry up the plug button to expose
air adjustment screw. Adjust the screw up or down to find
the best Flame Signal or until repeatable and stable lightoffs are achieved. Ignitor airflow is decreased as the screw
is turned clockwise, and increased as it is turned counterclockwise. Generally 3 to 5 turns up from full closed (screw
bottomed out) works best.
■When adjustments are completed, replace plug button to
protect adjustment screw
X FLAME SAFEGUARD
WARNING: Explosion hazard. Do not use this device
if it gets wet. It can malfunction and cause serious
injury or death. Replace any device that has been wet.
Standard Incinomite J Series burners are equipped with a
Honeywell RM7890 microprocessor based burner control
employing a flame rectification system of flame detection.
Burner construction for special codes and/or insurance
requirements such as Factory Mutual or Industrial Risk
Insurers (IRI) may require alternate controls. (Refer to
Section XI SPECIAL EQUIPMENT). A safe start and run
control sequence is provided with instantaneous response
to presence or loss of flame signal. Flame failure response
time is .8 seconds. Pilot Flame Establishing Period (PFEP)
is field selectable from 4 or 10 seconds. The RM7890
features a plug in amplifier. Five LED’s (light emitting
diodes) are provided to display sequence information.
Refer to the Honeywell RM7890 literature for detailed
operating information, configuration requirements, testing,
and service.
FIGURE 3 Control Components -7-
INITIATE (“POWER” LED is lit).
■ The RM7890 enters the INITIATE sequence when it is
powered. The INITIATE sequence lasts for ten seconds
unless the voltage or frequency tolerances are not met
(refer to Honeywell RM7890 literature for criteria). When
tolerances are met, the INITIATE sequence will restart. If
the condition is not corrected and the hold condition exists
for four minutes, the RM7890 will lock-out. causes for hold
conditions in the INITIATE sequence are in the Honeywell
RM7890 literature.
STANDBY (“POWER” LED is lit).
■ The RM7890 is idle in this state of sequencing. When the
burner switch, limits, operating limit controls, and all
microprocessor monitored circuits are in the correct state
for RM7890 to continue, sequencing will advance to
IGNITION TRIAL.
IGNITION TRIAL
1. PILOT FLAME ESTABLISHING PERIOD (PFEP)
A. The pilot valve (“PILOT” LED will be lit) and spark
generator are energized.
B. Flame must be proven by end of the 4 or 10-
second PFEP to allow the sequence to continue. If
flame is not proven by the end of PFEP, a safety
shutdown occurs.
2. MAIN FLAME ESTABLISHING
■ After the ignition trials, and with the presence of flame,
the main valve is energized. (“MAIN” LED will be lit.) If a
flame-out occurs, the RM7890 will lock-out or recycle within
.8 seconds. Refer to Honeywell literature for proper
configuration.
RUN
■ The RM7890 is now in RUN mode and will remain in run
mode until the controller input opens, indicating that the call
for heat has been satisfied or a limit has opened. Once this
occurs the RM7890 will sequence back to the STANDBY
mode.
Notes: 1. During STANDBY and during RM7890
sequencing the “POWER” LED will blink every
four seconds. This is normal.
2. The “ALARM” LED will be lit in the event of
any flame failure.
3. To maintain proper operation of this device it
MUST be electrically grounded. Refer to
Honeywell RM7890 literature for criteria.
XI SPECIAL EQUIPMENT (OEM VERSIONS)
Special equipment, either factory or field installed, can
cause variations in the procedures and descriptions given
in this manual. Generally, any burner ordered with special
factory installed equipment will be supplied with the
appropriate wiring diagram and related instruction manuals
from the special equipment manufacturer. Consult these
manual to identify any differences in construction,
operation, and testing. Field installed special equipment is
the responsibility of the installing contractor. For example,
when a high/low gas pressure switch is used, the high gas
pressure setting must be higher than the maximum
manifold pressure during initial start-up and the low
pressure setting must be set below the normal minimum
inlet pressure to prevent nuisance shutdowns during the
start-up procedure.
■After the burner in started, the low pressure setting should
be raised until the burner shuts off. Reduce the setting and
set the low pressure switch to restart the burner. Reduce
the high pressure setting until the burner shuts off. Then
raise the setting slightly and reset the high pressure switch
to restart the burner. Do not make the adjustments too
close to trip points or nuisance shut downs may occur. Any
time the burner gas supply is shut off with the main manual
valve, the low pressure switch will require resetting.
■IIf any doubt exists concerning burner operation when
special equipment is involved, contact the installing
contractor or MIDCO INTERNATIONAL INC. (front cover).
FIGURE 4 General Burner Head Assembly
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XII MAIN AUTOMATIC AND IGNITOR GAS
VALVES
Both valves are single function on-off type with automatic
closing on current failure. Replace entire valve if valve
fails to open when power is applied or if leakage is
detected on standby.
XIII BLOWER ASSEMBLY
Model J81A-3 uses a 1550 RPM shaded pole motor with
auto-reset overload protection. It contains a centrifugal
Interlock Switch which is connected in the control circuit to
prevent burner operation if the motor fails. Model J121A-3
is equipped with 1⁄6 HP split phase 3450 RPM motor. It may
contain either a manual or auto-reset overload protector. It
has no interlock, this function being performed by an Air
Pressure Switch on the burner.
Both motors feature permanently lubricated ball bearings
that require no routine oiling maintenance.
■ Cleaning of the blower wheel is usually the only service
required. Need for cleaning is required if the inlet screen or
blower wheel shows an accumulation of dust and lint. The
motor air cooling vents should also be cleaned at this time.
■ If the motor must be replaced, disconnect the motor wires
from the burner terminal strip and thermal switch. Remove
the blower inlet screen and blower wheel and remove the
motor case bolt nuts and lockwashers.
■ When remounting the blower wheel, the distance from
the wheel and the outside of the blower housing air inlet
side plate should be 5⁄16".
■ The switch mechanism is a bi-metallic disc that snaps
over when it is heated to the set temperature. The switch is
mounted so that the disc bears against the side plate of the
blower housing.
■ Testing the switch to prove that it is functional can be
done by removing the ignitor assembly and blowing hot air
through the opening toward the blower inlet. If hot air is not
available, remove the switch and check for continuity. With
the switch cool, there should be continuity between
terminals 1 (black wire) and 3 (red/white). To simulate the
“hot” condition, place the switch on a firm surface and apply
finger pressure to the switch disc. When the disc “snaps”,
there should be continuity between terminals 1 and 2
(yellow/black wire).
XIV THERMAL SWITCH
The Thermal Switch is a heat sensitive single pole double
throw snap switch that energizes the blower motor to
provide cooling air if, because of a heat back up through the
burner when the motor is off, the temperature of the blower
housing reaches 160° F. The thermal switch is not wired
into the gas valve circuit and does not turn valve off when
activated by heat back up.
FLAME
SENSOR
ELECTRODE
FIGURE 5 Type “3” Ignitor and Regulator Assembly
-9-
TROUBLE CHART
Make sure the switch or timer is calling for heat. Defective wiring or loose connections can simulate the component
defects outlined below. Check associated wiring before replacing a component.
ELECTRICAL AND FLAME CHECKS MUST BE MADE IN THE ORDER LISTED.
I. MOTOR WILL NOT RUN.
A . Confirm 120 volts between strip terminals.
1. L2 and L1: No voltage, Fused Disconnect off or
Fuse open.
2. L2 and 3: No voltage, Safety Controls open.
3. L2 and 10: No voltage, Burner Switch or
Timer open and/or Remote Switch or Timer
open.
4. L2 and 4: No voltage, optional high or low gas
pressure switch is tripped.
5. L2 and Thermal Switch Terminal 1 (black wire):
a.No voltage, Thermal Switch is defective.
b.Voltage present, defective Motor.
II. MOTOR RUNS CONTINUOUSLY, BUT NO FLAME
AND BURNER HOUSING COOL.
A. Make certain Flame Safeguard lockout switch is
not tripped.
CAUTION: Tests are valid only during the 4 or
10 second trial for ignition. Main Manual Shut-Off
Valve must be closed and Manual Ignitor Valve
open.
1. Confirm 120 volts on strip terminals L2 and 5.
a.Voltage present: Continue to Step 2.
b.No voltage:
J81A - Motor Interlock Switch defective.
J121A - Blower Air Switch defective.
2. Confirm 120 volts between strip terminal L2 and
terminal 6.
a.Voltage present, continue to Step 3.
b.No voltage, Flame Safeguard defective.
3. Confirm 120 volts on strip terminal L2 and 7.
a.Voltage present, continue to Step 4.
b.No voltage, Flame Safeguard defective.
4. Check for ignition spark (spark length
approximately 1/8").
a.Between spark generator hi-voltage terminal
and ground: No spark, defective Spark
Generator.
b.Between spark electrode wire and chassis
ground: No spark, Spark Generator defective.
c.For checking spark gap between Spark
Electrode and Ground Barrier, refer to PART
2 SERVICE VIII IGNITOR AND
REGULATOR ASSEMBLY, SPARK TEST.
5. Connect manometer to ignitor gas pressure
test tap, and check pressure during trial for
ignition period.
a.No pressure, confirm that pressure of at least
5.5" W.C. is available at the inlet of the Ignitor
Gas Valve, and repeat Step 5. If still no
ignitor gas pressure, ignitor gas valve defective.
b.Ignitor gas pressure 3.0" to 4.0" W.C.,
continue with Step 6.
c.Adjust the ignitor regulator to 3.5" W.C. while
gas is flowing.
6. Open the charging door, make sure any door
open interlock is temporarily by-passed and
repeat trial for ignition.
a.Open Main Manual Shut-Off Valve. With main flame
present, close charging door, remove temporary door
open interlock and check incineration chamber
pressure. Burner peep hole can be used for access
to obtain approximate reading (See Figure 3). Make
sure sensing tube extends into the incineration
chamber at least 6". Pressure should be between
0" to minus 0.5" W.C. for J81A, 0" to minus 1.0" W.C.
for J121A. If pressure is on the high negative side of
the range, increase the ignitor flame gas pressure to
4.0" to 5.0" W.C.
b.No flame present, clean and reset electrode
assembly per Figure 5 and repeat Step 6a.
III. IGNITOR FLAME ON ONLY DURING THE 4 or 10
SECOND TRIAL FOR IGNITION.
A. With motor running, confirm 120 volts as follows:
1. Between strip terminals L1 and L2: 120 volts
present, voltage OK.
2. Between strip terminals L1 and Ground: 120
volts present, ground OK.
3. Between strip terminals L2 and Ground: No
voltage, neutral OK.
B. Follow test procedure as specified in Step II.A.
1. Disconnect Flame Electrode Wire and check
for continuity.
2. Connect DC voltmeter in test jack in amplifier.
With ignitor flame on, reading should be at 2 or
more volts DC and steady. Adjust ignitor gas
pressure to obtain acceptable signal and note
gas pressure and signal strength for future
reference.
C. If all checks listed above were satisfactory and
the ignitor will not stay lit, Flame Safeguard defective.
IV. IGNITOR LIGHTS BUT NO MAIN FLAME.
A. Confirm 120 volts between strip terminal L2 and 8.
1.120 volts present, continue with Step B.
2.No voltage, Flame Safeguard defective.
B. Connect manometer to Main Automatic Valve
downstream pressure tap.
1. No gas pressure when valve is energized.
a.Confirm that pressure of at least 5.5" W.C.
NATURAL, 8.0" W.C. PROPANE, is available
at the inlet of the Main Automatic Valve.
b.Pressure at inlet side OK, Main Automatic
Valve defective.
V. SHORT MAIN FLAME.
A. Low gas pressure.
B. Air shutter open too far.
C. Input adjuster not set properly.
VI. LONG HAZY MAIN FLAME.
A. High gas pressure.
B. Air shutter closed too far.
C. Insufficient free air in incineration chamber.
D. Dirty blower wheel.
E. Input adjustor open too far for air shutter setting.
VII. GAS FAILS TO SHUT OFF.
A. Main Automatic and/or Ignitor Gas Valve defective.
-10-
B. High gas pressure.
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