Midco J121-DS User Manual

Do not store or use gasoline or other

flammable vapors and liquids in the

vicinity of this or any other appli

-

Installation and service must be per

-

formed by a qualified installer, service

: 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

Identifies unsafe practices which would result in minor personal injury or product and property damage.

Installation and Service Instructions

602

8471 15

Printed in USA

The INCINOMITE Model J121-DS gas burner features direct main
flame spark ignition and solid state electronic flame verification.

In the United States, installation must conform with local

codes or, in the absence of local codes, National Fuel
Gas Code , ANSI Z223.1-latest edition(s) available from
American 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.

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-B149.1 or 2.

INSTALLER: Inform and demonstrate to the user the
correct operation and maintenance of this gas
utilization equipment. Inform the user of the hazards
of storing flammable liquids and vapors in the vicinity
of this gas utilization equipment and remove such
hazards. 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.

Incinomite

Model J121-DS

Gas Burner

WARNING: If the information in

these instructions is not followed
exactly, a fire or explosion may result,
causing property damage, personal
injury or death.

ance.

WHAT TO DO IF YOU SMELL GAS

• Do not try to light any appliance.

• Do not touch any electrical
switch; do not use any phone in
your building.

• Immediately call your gas
supplier from a neighbor's
phone. Follow the gas suppliers'
instructions.

• If you cannot reach your gas
supplier, call the fire department.

agency or the gas supplier.

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:

Midco International Inc.

4 140 West Victoria Street Chicago, Illinois 60646
tel [phone] fax [phone]
web www.midco-intl.com e-mail [e-mail]

Quality Designed for Proven Performance

Part 1 Installation

Specifications

Primarily dry material such as paper, rags and wood. Burner normally

Consisting of approximately equal portions, by weight of No. 1 and No.

Organic materials such as small carcasses and waste from hospital

the heat required to maintain the discharge temperature of the flue products as specified

Make sure that the incinerator room has sufficient ventilation to provide the necessary

combustion air for the burner fuel, the waste material and any other appliance that would

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

1

BURNER AIR DELIVERY

Approximate Air Delivery at Zero Draft….....180 SCFM

2

MINIMUM GAS PRESSURE LISTED FOR PURPOSE OF
INPUT ADJUSTMENT

(Take Pressure at Inlet Tap of Main Automatic Valve )

NATURAL………………………………………………..5.5" W.C.
PROPANE……………………………………………….8.0" W.C.

BURNER FIRING RATE (NATURAL OR PROPANE)

All Ratings Based on 1000 BTU/cu. ft. NATURAL, 2500 BTU/cu. ft. PROPANE at Sea Level

MINIMUM……………………………………………... 100 MBH

3

4

MAXIMUM (With Combustion Air From Burner Only)

20% Excess Air……………………………900 MBH
0% Excess Air (stoichiometric)……..….1080 MBH

MAXIMUM (With Combustion Air From Burner Blower

and Additional Air Available in Combustion Chamber.)
NATURAL Gas 5.5" W.C. or PROPANE Gas at 11.0" W.C.
Gas Pressure at Main Automatic Valve……….1,200 MBH

ELECTRICAL SUPPLY……………………120/1/60; 4.5 amps
BURNER ON-OFF CONTROL……………Toggle Switch.
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 UL recognized, CGA listed, CSA certified

Part 1

Installation

I Primary Chamber Fuel Input

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. De-rate burner for altitudes over 2,000 feet by 4% for each 1000 feet of
additional elevation.

4. 100 MBH = 100,000 BTU/Hr.

5. Kit is available for field installation.

No. 1 Waste:

required only for light-off.

No. 2 Waste:

3 waste; 70 lbs. per 100 MBH.

No. 3 Waste: Wet material such as garbage; 25lbs. per 100 MBH.

No. 4 Waste:

operating rooms or pathological laboratories; 13 lbs. per 100 MBH.
NOTE: The burner input required for the secondary chamber must be determined from

by the EPA for the type of waste involved and the location of the incinerator.

______________________________________________________

II Indoor Ventilation

draw its air from the same enclosed area.

negative pressure in the room.

2

3

Part 1 Installation

Part 1

Installation

Continued

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.

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 Tube (4¼" 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

*Formerly referred to as

FLUE PIPE

Figure 1 Typical Installation

______________________________________________________

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

Part 1 Installation

Part 1

Installation

Continued

chamber over-fire draft, 0 to minus 0.5" W.C., 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-latest
edition "National Fuel Gas Code", or latest edition available from American National
Standards Institute to prevent tampering.

______________________________________________________

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.

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.

For full input, refer too SPECIFICATIONS, page 2, for minimum gas pressure

required. For reduced capacities, refer to Firing Rate Curves, Table 2.

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.
ALWAYS confirm that at least the minimum rated pressure is being supplied
during regulator adjustments, and NEVER BOTTOM 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 (NATURAL
gas 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.

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.

CAUTION: If the test pressure is over 0.5 PSIG, the test must be made
without any burner components connected, including Main Manual Shut-Off
Valves.

WARNING: EXPLOSION HAZARD. DO NOT USE OXYGEN FOR PRESSURE
TESTING. AN EXPLOSION COULD OCCUR DURING INITIAL START-UP.

NPT
PIPE
SIZE

3/4"

1"
1 1/ 4"
1 1/2"

2

4

TYPE

OF

GAS

Natural

Propane

Natural

Propane

Natural

Propane

Natural

Propane

Natural

Propane

Table 1 Schedule 40 Pipe Capacities in MBH

APPROXIMATE CAPACITY-MBH

LENGTH OF PIPE / FEET

10 20 40 60 100

275
450

520
800

800

---

---

---

---

---

200
300

350
550

730
800

800

---

---

---

130
200

245
385

500
790

760
800

800

---

100
165

195
300

400
630

610
800

800

---

125
150

235
300

480
460

725
800

800

---

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

5

Part 1 Installation

Part 1

Installation

Continued

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- 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 electronic control, causing it to malfunction.

The frame of the burner should be well grounded. A terminal is provided in the

control box for positive grounding.

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.

______________________________________________________

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 PROPANE 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.

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.

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. Let motor run long

enough to accomplish four air changes. Note that motor will continue to run
after Electronic Control lockout occurs.

6. Open the incinerator charging door. making sure any Door Open interlock is

temporarily bypassed.

7. Turn off the Burner Switch or Timer for at least 30 seconds to reset Electronic

Control (see Section XIII ELECTRONIC CONTROL SYSTEM). Open the
Main Manual Shut-Off Valve.

8. Turn on the Burner Switch or Timer. Burner Ignitor and main flame should

light during the 6 second trial for ignition after the motor reaches operating
speed. If the Ignitor and Main Flame fails to light during the 6 second trial for
ignition, it is probably due to air in ignitor gas line. Repeat from step 7. Then, if

necessary, refer to the Trouble Chart to isolate the problem.

WARNING: Repeated unsuccessful attempts to light will result in

accumulated gases in incineration chamber. To prevent these gases

Part 1 Installation

Part 1

Installation

Continued

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
ignitor 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 current with a micro-ammeter and adjust Ignitor Regulator slowly for
highest steady 2 or more microamps.

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, with the Ignitor and Main
Flame on, turn the Main Gas Input Adjusting Screw (see Figure 4) until the
desired input rating is reached (refer to Table 2). Turning of adjustment screw
counterclockwise increases gas flow; clockwise reduces flow. If Main Flame
gas pressure requires adjustment, refer to SECTION V PIPING SUPPLY.

11. 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.

GAS PRESSURE AT MAIN AUTOMATIC VALVE (INCHES WATER COLUMN)

Manifold Gas Pressure in Inches W. C.Manifold Gas Pressure in Inches W. C.

PROPANE Gas

2,500 BTU / Cu. Ft.

(with 5/8" Main Gas Port)

NATURAL Gas

1,000 BTU / Cu. Ft.

(with Main Gas Tube

only, no Gas Port)

6

Input in MBHInput in MBH

Table 2 Firing Rate Curves

7

Part 1 Installation

Figure 2 Wiring Diagram

Figure 3 Control Components

Part 1 Installation

Part 1

Installation

Continued

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

Then divide by 1,000 for MBH value.

= BTU / Hr.

Part 2 Service

VIII Ignitor and Regulator

Part 2

Service

Assembly

EXAMPLE: 3600 x 1 x 1000*

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.

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

WARNING: BE SURE THAT THE MANUAL VALVE AND BURNER
DISCONNECT SWITCH ARE TURNED OFF BEFORE ANY PARTS ARE
REMOVED FOR SERVICE.

The Ignitor and Regulator Assembly is removed as a unit. Disconnect the ignitor gas
line and electrode wires, remove the two mounting screws and pull out the assembly.

When the ignitor gas pressure is in the proper range (see Table 3) 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 cause
frequent Electronic Control 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
current. With the Electronic Control energized, a good reading should run steady 2 or
more microamps.

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 3.

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.

= 180,000 BTU / Hr. = 180 MBH

8

9

Consumer Instructions

Part 2

Service

Continued

TYPE OF

GAS

Natural

Propane

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 6-second 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.

CAUTION: Circuit has 30,000 volt open circuit potential.

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.

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.

______________________________________________________

IGNITOR

ORIFICE DIA.

.070 ( #50 DR )
.063 ( #5 2 DR)

TABLE 3 Ignitor Firing Rate

RECOMMENDED IGNI-

TOR GAS PRESSURE

3.5" W.C.

3.5" W.C.

IGNITOR

GAS RATE

13 MBH
15 MBH

VIII Ignitor Gas/Air

Adjustment

X Main Automatic Valve

XI Blower Assembly

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 light-offs 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" behind the Ignitor Orifice (refer to Figure 5). 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 light-offs are achieved. Ignitor airflow is decreased as the screw is turned
clockwise, and increased as it is turned counter-clockwise. 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.

______________________________________________________

The valve is a 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
defected on standby.

______________________________________________________

Model J121DS 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. The motor features per ­manently lubricated ball bearings that require no routine oiling maintenance.

Trouble Chart

Part 2

Service

Continued

XI Blower Assembly

Continued

XII Thermal Switch

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. Remove the blower inlet screen and blower wheel and remove the motor case
bolt nuts and lock washers.

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 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.

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/black wire). 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 (red wire).

______________________________________________________

XIII Electronic Control System

The Electronic Control is a 24 volt AC, solid state electronic device that
automatically ignites and monitors the flame. It has an integral high voltage
transformer and, upon flame startup, applies high voltage to the spark electrode and
24V to the Main Automatic Gas Valve. When the flame is proven, the spark is
terminated and the burner run continues.

If the flame is not proven within 6 seconds, or if the proof of flame is lost during the
burner run and not re-established within 6 seconds, the Control will shut off the Main
Automatic Gas Valve and LOCK OUT. To reset the Control for restart, turn off the
Burner Switch or Timer for at least 30 seconds and then turn back on.

10

Figure 4 General Burner Assembly

11

Consumer Instructions

Part 2

Service

Continued

If the Electronic control is changed, the replacement must be identical as to the

make and model number, or must be an authorized substitute.

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.

Trouble Shooting

FIGURE 5 Ignitor and Flame Sensor Assembly

TROUBLE CHART

Make sure the thermostat and operating controls are 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 120V between strip terminals:

1. L2 & L1 no voltage - Fused disconnect off or Fuse open.

2. L2 & 3 no voltage - Optional on/off and/or safety controls open.

3. L2 & 4 no voltage - Burner Switch or Timer open and/or Remote Switch or Timer open.

4. L2 & Thermal Switch terminal 1 (black wire).
a. None - Thermal Switch is defective.
b. Yes - Motor is defective.

II. MOTOR RUNS CONTINUOUSLY, BUT NO FLAME- HOUSING COOL

A. Confirm that Main Manual Shut-Off Valve is open.
B. Check for 120V between strip terminals 4 and L2.

1. Yes - turn Burner Switch or Timer off for a minimum, of 30 seconds to RESET Electronic

Control.

2. No voltage, Thermal Switch is defective.

Trouble Chart

Trouble Shooting

Continued

C. Check for 24V* between strip terminals 6 to 10. No voltage, transformer is defective.
D. Check for 24V* between strip terminals 5 and10. No voltage, motor interlock switch is

defective.

E. Check for 24V* between Electronic Control 24 (PWR) terminal and strip terminal 10. 24V

yellow wire from strip terminal 10 is defective.

F. Check for 24V* between Electronic Control 24 (GND) terminal and strip terminal 10.

No voltage, red wire from terminal strip 5 is defective.

G. Turn burner control off for a minimum of 30 seconds to RESET Electronic Control for

each of the following steps.

CAUTION: Tests are valid only during the 6 second trial for ignition.

1. Check for 24V* between Electronic Control Valve terminal and strip terminal 10. No volt
age, Electronic Control or Fuse is defective.

2. Check for 24V* between strip terminals 7 and 10. No voltage, blue wire from strip
terminal 7 is defective.

3. Check for ignition spark (spark length approximately 1/8"):

a. Between Electronic Control HI VOLTAGE terminal and earth ground. No spark,

Electronic Control or Fuse is defective.

b. Between electrode wire and Spark Electrode. No Spark, Electrode wire is defective.
c. Check for spark between Spark Electrode and ground barrier. See Figure 5. If

ignitor tip is not visible with burner mounted, but spark can be heard, continue with
Step G4. If spark cannot be heard, refer to Section VIII IGNITOR AND REGULATOR
ASSEMBLY for spark test.

4. Connect manometer to Ignitor Gas Pressures Test Tap and, during 6 second trial for

ignition period, check gas pressure.

a. No pressure, confirm that pressure of at least 4" W.C. is available at inlet of

automatic gas valve (connect manometer to valve upstream tap) and repeat Step G4.
If still no ignitor gas pressure, valve is defective.

b. Ignitor gas pressure 3" to 4" W.C., continue with Step G5.
c. .Adjust the ignitor regulator to 3.5" W.C. while gas is flowing.

5. Open charging door, make sure any Door Open interlock is bypassed, and repeat trial

for ignition.

a. With flame on, close charging door and check combustion chamber pressure, burner

peep hole can be used for access to obtain approximate reading. Make sure sensing
tube extends into the combustion chamber for at 6". Pressure should be
between 0" and minus 0.5" W.C. If pressure is on the high negative side of the range,
increase the ignitor gas pressure to 4" or 5" W.C.

b. No flame, clean and test ignitor assembly per Section VIII IGNITOR AND REGULATOR

ASSEMBLY.

12

III FLAME ON ONLY DURING 6-SECOND TRIAL FOR IGNITION

A. With motor running check burner line voltage terminals for 120V as follows:

1. Between strip terminals L1 and L2 - 120V: voltage OK.

2. Between strip terminals L1 and GND.TERM - 120V: ground OK.

3. Between strip terminals L2 and GND.TERM. - no volt age: no back-feed neutral OK.

B. Follow test procedure as specified in Step II G.

1. Connect DC microamp meter in series with sense wire and Electronic Control SENSE

terminal. With flame on, flame signal should be steady and at least 2 microamps.
Check sense wire for continuity Adjust ignitor gas pressure to obtain acceptable
signal and note gas pressure and signal strength for future reference.

IV. SHORT FLAME

A. Low gas pressure
B. Air shutter open too far
C. Input adjuster not set properly

V. LONG HAZY FLAME

A. High gas pressure
B. Air shutter closed too far
C. Insufficient free air in combustion

chamber
D. Dirty blower wheel
E. Input adjuster not set properly

tel [phone] fax [phone] web www.midco-intl.com email [e-mail]

Midco International Inc.

4140 West Victoria Street * Chicago, Illinois 60646

VI. GAS FAILS TO SHUT OFF

A. Defective automatic valve
B. High gas pressure

*Normal low voltage: Motor running - 24V minimum
Automatic valve energized - 21V minimum

602

8471 15

Printed in USA