Page 1
The ECONOMITE Models 400B-02 and 400B-02P conversion burners are adaptable to most common central gas utilization
equipment, including up-draft gravity and forced circulation furnaces and boilers. Power burner design makes it perfectly suited
for oil burner replacement. For horizontal and downdraft gas utilization equipment, ECONOMITE Model DS45B conversion burner with direct spark ignition is recommended.
In the United States, installation must conform with local
codes or, in the absence of local codes, with Installation
of Domestic Gas Conversion Burners, ANSI Z21.8alatest edition and 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 dis
tributor (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. When the conver-
sion burner is used on Forced Air Central Furnace, the
two yellow and black warning labels in the literature enve
lope shall be at tached in accordance with Installation
Code, CGA Standard CAN /CGA1-B149,Clause 5.4.4.4.
Further reference should be made to the recommendation
of your fuel supplier.
INSTALLER: Inform and demonstrate to the user
the correct operation and maintenance of this gas
utilization equipment. Inform the userof the hazards of storing flammable liquids and vapors in
the vicinity of this gas utilization equipment and
remove such hazards. Affix this manual adjacent
to the conversion burner.
CODE COMPLIANCE IS THE SOLE RESPONSIBILITY
OF THE INSTALLER.
WARNING: If the information in
these instructions is not followed
exactly, a fire or explosion may result,
causing property damage, personal
injury or death.
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
Installation and service must be performed by a qualified installer, service
agency or the gas supplier.
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.
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 nota-
tions 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.
ANSI Z21.17$CSA2.7
CONVERSION BURNERS
Installation and Service Instructions
Midco International Inc.
4140 West Victoria Street Chicago, Illinois 60646
tel 773.604.8700 fax 773.604.4070 web www.midco-intl.com
201
8470-75
Printed in U.S.A.
Economite 400B-02
Conversion Burners
Page 2
Notes:
* Model 400B-02P is equipped with a 4-Function Redundant Main Automatic Valve.
** SCFM=Standard Cubic Feet/Minute
*** Ratings based on 1,000 BTU/cu. ft. NATURAL, 2,500 BTU/cu. ft. PROPANE at Sea
Level.
**** 1 MBH=1,000 BTU/Hr.
One gallon of fuel oil=140,000 BTU.
Derate burner for altitudes over 2,000 feet by 4% for each 1,000 feet above sea level.
CAUTION: The ECONOMITE 400B-02(P) is not intended for outdoor installation and must be protected from excessive moisture. Provide adequate clearance for service and proper operation.
If the former automatic oil burner gave trouble-free operation, it is probable that the gas utilization equipment area has sufficient infiltration of air for combustion and dilution of flue gases.
Nevertheless, the area must be checked:
Open basement or utility areas of normal construction, without storm windows or tight doors,
will generally allow sufficient air infiltration. However, if the gas utilization equipment is located
in a tight or separate room, ventilation to an open area as described above will be required.
Install two permanently open grilles, each sized on the basis of one square inch free area per
1,000 BTU (but not less than 100 square inches) of the total input rating of all gas utilization
equipment in the combined space. One grille should be located within 12 inches of the ceiling,
the other within 12 inches of the floor.
If the gas utilization equipment is located in an area of unusually tight construction, or if an
exhaust fan, kitchen ventilation system, clothes dryer and/or fireplace is installed in the building, provision must be made for an outside air supply near the gas utilization equipment area.
Install permanently open grilles sized at not less than one square inch free area per 4,000 BTU
of burner input. When ventilating through horizontal ducts, grilles should be sized at not less
than one square inch free area per 2,000 BTU of burner input. In any case, the minimum
dimension of rectangular air ducts shall not be less than 3 inches.
In Canada, for detailed ventilation requirements, refer to standard CAN/CGA 1-B149.1 or .2
and/or local codes.
Clean the gas utilization equipment, heat exchanger interior, combustion chamber, and flue
connections. Remove all adhering tars, scale, dirt and soot. Inspect for actual leaks and/or
potential leaks.
Cement all joints, including those in the gas utilization equipment base and around door
frames, to prevent leakage into or out of the combustion chamber.
The access or firing door should open easily to relieve pressure. If positive latches exist,
they should be modified to permit easy opening; a spring loaded door holder is recommended.
On all boilers, make certain the pressure relief safety valve is in good operating condition.
Specifications
2
Model 400B-02 NATURALGas only
Model 400B-02P PROPANE Gas*
Air Delivery
(Approximate air delivery at zero draft)
Maximum Firing Rate***
Minimum Firing Rate***
Tube Diameter
Tube Length
Minimum Combustion Chamber Size
400 MBH
300 MBH
200 MBH
Gas Pressure Required
NATURAL
PROPANE
Standard Voltage
Pilot Safety
85 SCFM**
400 MBH****
200 MBH****
4 inches
9 inches
10" W x 16
1
/2L or 15" dia.
9" W x 14" L or 13" dia.
7" W x 11" Lor 10" dia.
5.0" to 14.0" W.C.
11.0" to 14.0" W.C.
120 Volts 60 Cycle
Thermoelectric, 100% shut-off
I Ventilation
II Preparation of the Gas
Utilization Equipment
Part 1 Installation
Page 3
A combustion chamber liner is normally required to protect non-heat transfer surfaces and to
provide a radiant bed for rapid heat transfer to the primary surfaces of the heat exchanger. In
most cases, the oil burner combustion chamber
liner formerly used can be used, if in good condition.
In the case of wet base boilers, where the
entire combustion chamber is comprised of heat
exchange surfaces and no combustion chamber
liner was provided for oil firing, a liner is usually
not required for the ECONOMITE. However, a
liner or target wall may be necessary if the combustion chamber is unusually short, in order to
avoid flame contact on the heat exchanger walls
or flueways.
If a built up chamber liner is required, use
2300°F minimum insulating material.
The burner tube, or the stainless steel sleeve
that is included with the burner, must be sealed
air tight into the combustion chamber liner opening with refractory material as shown by Figures
1,2 and 7. The sleeve is preferred as it is
designed to properly locate the end of the tube relative to the inside wall of the combustion
chamber, and to permit burner removal without breaking the seal.
CAUTION: In no case should the burner tube be allowed to extend into the cham-
ber proper; it must be set at least 1" short of the inside surface , because high combustion chamber temperatures will cause premature thermocouple and pilot deterioration.
Special heat resistant alloy extension tubes and instructions are available for those applica-
tions where the burner tube is too short to reach the combustion chamber (such as old-fashioned gravity warm air furnace installations).
WARNING: Burner cabinet must be
mounted in orientation shown in figures 1
and 2. Any other mountings may cause a
dangerous condition, and will void burner
warranty and agency approvals. Nonstandard arrangements may be available
for some models; consult factory for
details if required.
Before permanently setting the burner in place,
check venturi casting openings and pilot assembly to make sure they are free of foreign materials. See Figure 8.
WARNING: The chimney shall be
inspected for unsafe conditions such as
deteriorated masonry and excessive soot
or other blockage or potential blockage.. Installation must conform with local
codes or in the absence of local codes with ANSI Z21.8 latest edition and NFPA,
ANSI Z223.1 latest edition.
WARNING: The Vent Connector shall not be connected to a chimney already venting solid fuel burning
appliances, an incinerator or an open fireplace.
The Vent Connector shall be made of non-combustible, corro-
sion resistant material capable of withstanding the vent gas temperature produced by the gas utilization equipment and of sufficient thickness to withstand physical damage.
The Vent Connector shall be as short as possible. The
entire length shall be readily accessible for inspection, cleaning and replacement.
The length of horizontal uninsulated Vent Connector between chimney and a single gas uti-
liza
tion equipment shall not exceed 75% of the height of the chimney above the connector, or
100% if the Vent Connector is insulated.
3
III Combustion Chamber
IV Chimney, Vent
Connector*,
and Draft Control
*Formerly referred to as Flue Pipe
Figure 1: Dry Base Boiler with Combustion
Chamber Liner (Warm Air Furnace
Construction is Similar)
Figure 2: Wet Base Boiler with
Combustion Chamber Unlined
Maximum
Firing Rate
Vent
Connector
250 MBH
320 MBH
400 MBH
7"
8"
9"
Table 1: Recommended
Vent Connector Sizes
Page 4
The Vent Connector shall be installed so as to avoid turns or other construction features
which create excessive resistance to flow of vent gas. It shall be installed without any dips sags
and shall slope upward at least 1/4" per
foot.
A manually operated damper shall
not be placed in the Vent Connector or
chimney of any gas utilization equipment.
The Vent Connector shall be firmly
attached to draft hood outlets and flue
collars. Joints between sections of connector piping shall be fastened by sheetmetal screws or other approved means.
The Vent Connector shall be supported
for the design and weight of the material
employed to maintain clearance and prevent physical damage and separation of
joints.
Gas utilization equipment requiring
controlled draft may be equipped with a
listed double acting barometric draft regulator, if approved by local codes. It
must be installed and adjusted in accordance with the manufacturer's instructions.
A draft hood or a barometric draft
regulator shall be installed in the same
room or enclosure as the equipment in
such a manner as to prevent any difference in the pressure between the hood
or regulator and the combustion air supply. In no case shall the relief opening of
the draft hood or barometric draft regulator be located at a point lower than the
top of the highest flue passage in the
equipment.
A device which will automatically
shut off gas to the burner in the event of
sustained backdraft is recommended if
such backdraft might adversely affect
burner operation or if flue gas spillage
might introduce a hazard. If such a
device is used, it shall be of the listed
type and installed and adjusted by a qualified service technician in accordance
with the manufacturer's instructions.
Installation wiring and grounding of the burner must conform to local codes, or in their absence
in the United States to National Electric code, ANSI/NFPA No. 70-latest edition; in Canada,
to Canadian Electrical Code Part 1, CSA Standard C22.1.
Use copper wire not less than 14 gauge for line voltage wiring. Hook up to a dedicated line
with an on-off disconnect switch and a minimum 10 amp breaker.
The frame of the burner should be well grounded. Normally the piping and/or electric con-
duit will provide sufficient grounding. However, a terminal is provided on the terminal strip for
positive grounding where insulated pipe couplings are used or where any doubt exists regarding grounding sufficiency.
Confirm that the polarity is correct—hot wire strip terminal 1, neutral 2— and that the neu-
tral line is not subject to induced low voltage (check 2 to earth ground) from other equipment.
Each installation must include suitable limit controls. Existing oil burner combination limit
and operating controls are normally NOT SUITABLE for gas burner use.
Set the thermostat heat anticipator for the total current draw handled by the thermostat.
The current draw of the ECONOMITE 24V operating circuit is 0.3 amps on 400B-02 (NATURAL) and 0.7 amps on 400B-02P (PROPANE).
4
IV Vent Connector
Continued
V Electrical
Figure 3: Draft Hoods
Figure 4: Barometric Dampers
Figures 3 and 4: Copyright by the
American Gas Association. Used by
permission of the copyright holder.
Page 5
CAUTION: Do not
add any power consuming devices in the low
voltage circuit as overloading of the transformer can result. Do
not use Motor Relay to
operate any external
devices as the extra
load could damage the
relay contacts.
Note: If any of the original
wiring as supplied with the
conversion burner must be
replaced, it must be replaced
with type TFF wire or its
equivalent.
CAUTION: The available gas pressure should be within the limits shown in
the SPECIFICATIONS section. Excessive pressure will damage Combination
Valve and Regulator. If the supply pressure exceeds the 14.0" W.C. maximum, a
suitable intermediate main regulator must be installed ahead of the Main
Manual Shut-Off Valve shown in Figure 6.
The burner gas supply piping should branch off from the main line as close to the gas meter as
possible. Do not connect to the bottom of a horizontal section. Use new black pipe and malleable fittings free of cutting and threading burrs or defects.
Provide a sediment trap, union and 1/8" pressure tap in piping close to burner as shown in Fig 6.
Use pipe joint compound approved for use with Liquid Petroleum Gases.
Piping must comply with local codes.
To obtain the maximum firing rate of 400 MBH, the NATURAL gas supply piping must be sized to
provide minimum of 5.0" W.C. pressure (11.0" W.C. PROPANE) to the inlet of the Combination Valve
when the burner and all other gas utilization equipment are on.
Note: If there is more than 1.0" W.C.
differential in the inlet pressure to
the burner compared to when all
other gas utilization equipment are
off, refer to Section IX, last paragraph "CAUTION...".
CAUTION: Because it is
difficult to accurately control
pressure during supply pipe
leak test, it is recommended
that the Combination Valve
be disconnected. Exposing
the Combination Valve to pressures over 1/2 PSIG (14.0" W.C.) will damage the
valve and void all warranties.
DANGER: Explosion hazard.
Do not use oxygen for pressure testing.
An explosion could occur during initial start-up.
If the burner piping must be rearranged because of space limitations, be sure to carry out
the general arrangement shown in Figure 6. Install the Combination Valve in any position
except up-side down.
When the burner is installed in jacketed equipment, it is recommended that the
Combination Valve be left adjacent to the burner within the vestibule and the Main Manual
Shut-Off Valve be installed outside.
5
Figure 5: Wiring Diagram
Pipe
Size
3
/
4
1
11/
4
11/
2
250
400
400
300
350
400
400
200
200
350
400
400
200
300
400
400
200
300
400
400
Type
of Gas
NATURAL
PROPANE
NATURAL
PROPANE
NATURAL
PROPANE
NATURAL
Capacity-MBH
Length of Pipe
Table 2: Supply Pipe Capacities in MBH
10
20
40
60
100
V Electrical
Continued
VI Piping
(Terminal call-out may not be as shown)
Page 6
Standard burners are approved
for use with NATURAL or
PROPANE gas only, and should
be used only with the gas specified on rating plate.
A Standard Model 400B-02
burner is equipped with a single
seated Combination Valve and
is suitable for NATURAL gas
only. AStandard Model 400B02P is equipped with a double
seated (redundant)
Combination Valve and is suitable for PROPANE gas use.
WARNING: The
Model 400B-02 is not suitable for conversion to
PROPANE gas. Using
PROPANE gas in the
Model 400B-02 is a safety
hazard and will void the
approval listing and the
burner warranty.
Model 400B-02 (NATURAL gas burner is shipped with a .343 diameter orifice installed for an
input capacity range of approximately 200 to 325 MBH. AStandard Model 400B-02P
(PROPANE) gas burner is shipped with a .180 diameter orifice installed for an input capacity
range of approximately 225 to 260 MBH. If the required rate does not fall within the capacity
range of the installed spud, select the correct input capacity range from Table 3 and install the
spud with the correct orifice size (stamped with inch diameter) from the SPUD KIT bag. If the
required firing rate is at the minimum of a capacity range, select the next lower range spud.
TO CHANGE SPUD: Turn Manual Gas Cock Knob on Combination Valve to OFF. Remove
the Spud Holder. See Table 3, and Figure 6 or 7.
The Combination Valve Gas Pressure Regulator is set to provide 2.0" W.C. NATURAL (8.0"
W.C. PROPANE) manifold gas pressure for low to minimum spud capacity input. Both models
are shipped with the primary air controlling shutter set WIDE OPEN to provide a lean gas/air
mixture during the initial start-up. Do not change the Combination Valve Gas Pressure
Regulator setting at this time.
CAUTION: The approximate air and gas settings described above are for
initial start-up only. Final settings must be made in accordance with Section
VIII. Instructions for adjustment of the manifold gas pressure are detailed in
Section XI.
* Main Gas Spud Orifice
Size, approximate
Manifold Pressure.
Data shown is approximate and based on "0"
overfire pressure at sea
level.
6
VII Main Gas Spud
Figure 6: Piping Connections
Table 3: Main Gas Spud Capacity and Preliminary Gas
and Air Settings
VI Piping Continued
Page 7
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. 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 gas utilization
equipment.
3. To purge the gas utilization equipment and chimney of any accumulated gases, turn
Manual Gas Cock Knob on the Combination Valve to OFF, turn burner power on and set operating control to ON or thermostat to call for heat. Let the blower run long enough to accomplish
four air changes, but not less than five minutes.
4.
CAUTION: Make sure that the capacity range of the installed spud and the
preliminary primary air shutter settings are suitable for capacity rating of the
gas utilization equipment. Refer to Section VII and Table 3.
5. Stop motor by setting operating control to OFF or thermostat below room temperature.
6. Turn Manual Gas Cock Knob on Combination Valve to PILOT and depress knob, or red
button if so equipped. Hold firm and light pilot by depressing piezo ignitor button several times.
Pilot should light. Pilot may be viewed through Peep Sight located in Back Plate (See Figure
6). Failure to light is probably due to air in pilot gas line. Attempt several relights. Then, if necessary, refer to Trouble Chart or Section IX to isolate the problem.
WARNING: Repeated unsuccessful attempts to light pilot will result in accumulated gases in gas utilization equipment and chimney. To prevent these
gases from reaching an explosive level, periodically purge the gas utilization
equipment and chimney as described in Step 3 above.
7. With pilot lit, wait one minute; then release Manual Gas Cock Knob on Combination Valve,
or red button if so equipped, and turn to ON. if a pilot goes out when knob is released, turn to
OFF then PILOT and repeat purging and pilot lighting instructions detailed above. Incorrect
pilot flame gas pressure may prevent proper heating of thermocouple causing the pilostat safety control to drop out. Refer to Section IX for pilot adjustment.
8. Turn operating control to ON or set thermostat above room temperature. Main flame
should come on when the motor reaches operating speed. If not, refer to Trouble Chart. To
make a preliminary setting of the burner input, determine the manifold gas pressure required
from Table 3 and adjust the Combination Valve Pressure Regulator accordingly. See SectionXI.
9. To determine the firing rate for NATURAL gas, accurately time test dial for the number of
seconds for one revolution and use the following formula. All other gas utilization equipment
must be off.
Then divide by 1,000 for MBH value
For PROPANE gas, consult your supplier for method of determining firing rate.
10. Readjust the primary air shutter to provide a quiet, soft blue flame with well defined orange
and yellow tips for NATURAL gas or with well defined yellow tips for PROPANE.
11. Check the operation of the burner; start and stop it several times with the thermostat or
operating control.
12. With the burner running, check the operation of all limit and associated controls.
13. PERFORM THE FOLLOWING FINAL ADJUSTMENTS for combustion and flue gas tem-
perature. Take the flue gas samples and temperature immediately ahead of the draft control.
A. Check the draft control to make sure there is no spillage of flue products into the room.
B. Make the final setting of the primary air shutter by checking the flue gases with an
ORSAT or similar combustion instrument. The carbon monoxide content should conform
to local codes, or in their absence to the level specified in the United States or Canadian
Standard referenced on the front cover of this manual; and the carbon dioxide content
should be approximately 9.5% for NATURAL and 12.1% for PROPANE, or within the
limits prescribed by local codes.
C. The flue gas temperature should be above 325°F but not exceeding 550°F. Excessive
flue gas temperatures will result in low efficiencies. Low flue gas temperature may cause
excessive condensation. Reset gas input if necessary to adjust stack temperature.
14. FILL OUT THE INSTALLATION ADJUSTMENT DATA TAG and affix to the burner or gas
utilization equipment.
Note: For subsequent normal starting and shut-off procedure, refer to CONSUMER
INSTRUCTIONS or the instruction plate mounted on the burner.
7
VIII Initial
StartUp/Adjustment
3600 x test dial size x BTU value
No. of seconds for one rev. test dial.
= BTU/Hr.
3600 x 1 x 1000
20
= 180,000 BTU/Hr. = 180 MBH
Example:
Page 8
DANGER: Be sure that the Main Manual Shut-Off Valve, Combination Valve
and Burner Power Switch are turned off before removing any parts for service.
When the pilot gas pressure is in the proper range (see Table 4) lint, dust or corrosion is then
the usual cause for most pilot problems.
The Venturi Casting and Pilot Assembly are part of the drawer assembly which can be
removed as a unit. Remove the two back plate screws, two elbow screws. Disconnect thermocouple and pilot tube at Pilot Pressure Tap. Swing away Combination Valve and pull out drawer
assembly.
When servicing, clean the Venturi Casting Ports and Pilot Assembly, including the pilot ori-
fice, and the spark electrode. Also, examine the thermocouple. If there is any serious corrosion
or loss of metal at the tip replace the thermocouple.
Check that the pilot orifice diameter is
correct (see Table 4).
Make sure that the burner tube is prop-
erly positioned in the combustion chamber
entry. It must be set 1" short of the inside
of the combustion chamber as shown in
Figure 1,2, or 7. It must not protrude into
the chamber, because high combustion chamber temperatures will cause premature thermocouple and pilot deterioration.
If cleaning does not eliminate the lighting problem, further checks are required.
CAUTION: Do not indiscriminately increase pilot orifice diameter. Pilot troubles are rarely cured in this manner and new troubles may be introduced by
causing the pilot flame to float and lose contact with the thermocouple.
CAUTION: If there is more than a 1.0" W.C. differential between STANDBY
inlet pressure when all appliances are OFF, and the inlet pressure when the
burner and all other appliances are ON, a
1
/8 inch Maxitrol RV12-Series (or
equal) pressure regulator must be installed in the pilot gas line. With the adjustment screw wide open, set the pilot flame gas pressure at 4.0" W.C. for NATURAL gas, 8.0" W.C. for PROPANE.
1. Standby gas pressure-inches W.C.
2. The efficiency of the thermocouple and the pilotstat safety control can be determined by
timing the safety shut-off. With the burner power switch off and with the combustion chamber
cool, allow the pilot to operate at
least five minutes. Then turn off
the pilot and time the period until
a click is heard from the
Combination Valve. If less than
30 seconds, the thermocouple,
pilot flame adjustment, or the
pilotstat safety control of the
main valve is faulty.
3. An accurate check of the thermocouple and pilot flame adjustment can be made with a millivoltmeter. The thermocouple, when heated by the pilot, should develop at least 15 millivolts
minimum to 25 millivolts maximum open circuit (thermocouple disconnected from valve). If millivolt reading is above maximum, readjust pilot gas input slightly to reduce voltage. Check results
with blower motor off and on.
4. Tests to isolate thermocouple and/or valve pilotstat problems can be conducted under
closed circuit conditions (thermocouple connected to valve through an adaptor that provides for
connecting the millivoltmeter). If the thermocouple does not develop at least 7 millivolts when
the pilot flame is properly
adjusted, it is defective. If the
valve does not hold in with a
7 millivolts, the pilotstat is
defective and entire valve
must be replaced.
5. If the thermocouple
meets conditions of paragraph 3 or 4, but timing test
of paragraph 2 remains
under 30 seconds, the pilotstat safety control can be
suspected of being defective
and entire valve must be
replaced.
8
Nominal BTU/cu. ft. Value
NATURAL
over 14.0"
below 4.0"
4.0 to 7.0"
7.0 to 14.0"
over 14.0"
below 8.0"
8.0 to 11.0"
11.0 to 14.0"
PROPANE
See Section VI
Set pilot adjustment screw
wide open
Set pilot gas pressure at 6.5"
NATURAL, 7.5" PROPANE
REMARKS
Figure 7: General Assembly
Orifice Diameter
Pilot Gas Pressure
Approximate Capacity
.021
3.5-7"
PROP-2500
.012
7.5-11"
1000 BTU/Hr.
NAT-1000
Table 4: Pilot Specifications
IX Venturi Casting
and Pilot
Part 2 Service
Page 9
Check for possibility of reverse draft which can be caused by wind deflecting from an
obstruction in the proximity of the chimney exit or by exhaust fans in the building.
A continuous draft is required for the proper operation of the pilot. This is no problem in the
usual up-draft gas utilization equipment. However, in down-draft or horizontal gas utilization
equipment, especially during periods of infrequent operation, the available draft may become
nil and result in persistent pilot outages. ECONOMITE Model DS45B with direct spark ignited
main flame is recommended for those applications.
Maximum acceptable draft: minus 0.2" W.C.
Note: BEFORE SERVICING, mark with a scribe line or measure opening of primary air shutter
so that it can be reset to its original position following servicing.
Cleaning of the blower wheel is usually the only service required. Need for cleaning is indi-
cated if the air cage assembly shows an accumulation of dust and lint, or if the character of the
flame indicates a deficiency of air. Motor cooling air vents, if present, should also be cleaned at
this time.
The Blower side Plate, Motor and
Wheel are removed as an assembly.
Disconnect the motor wires from Burner
Terminal 2 and Motor Relay 4. Disconnect
the Motor Conduit from the Control Box
and remove the Side Plate screws.
The Blower Wheel is equipped with a
spring loaded centrifugal actuator to operate and electrical interlock switch, so as
to prevent the burner from firing if the
Blower Wheel is not running at its operating speed. When the motor is off, the
actuator spring forces the disk against the
switch plunger to push it past its operating
point. When running, the actuator pulls
the disk clear of the plunger.
To make a specific test of the interlock circuit:
1. Turn burner power OFF.
2. Turn Manual Gas Cock Knob on Combination Valve to OFF.
3. Disconnect the motor wire from Terminal 4 of the motor relay to keep the motor off.
4. Turn burner power ON and set the operating control to ON or thermostat to call for heat.
Check for 24V between the Combination Valve Terminals.
A. No voltage: Interlock Circuit OK.
B. Voltage present: check that switch bracket is screwed down tight (See Figure 9). If so,
without disconnecting switch wires, remove switch bracket and manually depress
switch plunger. If voltage is still present, or if the plunger has to be depressed to
where dimension A of Figure 9 is less than
9
/32" when switch clicks over, replace the
switch.
5. If the switch tests OK, check dimension Aof Figure 9 as follows:
Switch plunger free…………
9
/32"to 11/32"
Disk free………………..…
7
/32to 1/4"
Disk held all the way in….
15
/32" min.
6. If plunger dimension is wrong, replace switch. If disk dimension is wrong, check that the
actuator operates freely with a minimum movement of
1
/4" from the free position. If movement
is OK, reposition blower wheel on motor shaft, if not replace wheel.
IX Venturi Casting
and Pilot Continued
9
Figure 8: Venturi Casting and Pilot Assembly
Figure 9: Blower Assembly
X Blower Assembly
Page 10
The 24 volt Combination Valve serves four functions: 1. Main Manual Gas Shut-off, 2. Manifold
gas pressure regulation, 3. Automatic electric main gas valve; single seated on Model 400B-02,
double seated (redundant) on Model 400B-02P, and 4. Pilotstat safety control. Apilot adjustment
screw and filter are also included.
The pilot adjustment screw is located on the inlet end of the valve body. Remove plug for
access and turn clockwise to reduce flow.
The main gas regulator, which has an outlet pressure setting range of 2.0" to 4.0" W.C. NAT-
URAL (8.0" to 11.0" W.C. PROPANE) is factory set for a manifold gas pressure of 2.0" W.C. NATURAL (8.0" W.C. PROPANE). If pressure adjustment is required for setting capacity, remove regulator cap for access to slotted adjustment screw. Turning of adjustment screw counterclockwise
reduces pressure; clockwise increases pressure. Do not adjust past point where no change in
pressure is noted.
Note: Pressure setting can only be made with burner running and gas on. Manifold gas pressure
tap is located in spud holder (See Figure 6 or 7).
CAUTION: If gas supply pressure is below its specified range during adjustment, an overfire 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 gas pressure is being supplied to the burner during regulator
adjustments, and NEVER bottom out regulator screw.
If the pressure regulator fails to maintain a constant manifold gas pressure within ±0.1" W.C.,
and it is confirmed that the inlet gas pressure to the Combination Valve is a steady 14.0" W.C.
maximum during standby, and a steady 5.0" W.C. minimum with the flame on, the regulator portion
of the valve is defective and the entire valve must be replaced.
The pilotstat safety control may be suspect, if frequent pilot outages occur. Refer to Section
IX, 2 thru 5, for the method of isolating the problem.
If, on a call for heat, the main burner fails to operate even though the pilot is burning and the
motor is running, failure of the electric valve operator(s) may be indicated. Refer to the Trouble
Chart for further information.
10
Consumer Instructions
CAUTION: If the Combination Valve has been moved or replaced, soap bub-
ble test for leaks with the burner running.
If leakage through the valve occurs, as evidenced by an abnormally large yellow (sooty) flame
on standby, the entire valve should be replaced.
Keep the area around the burner clear and free of combustible materials, gasoline and other
flammable liquids or vapors. Do not obstruct burner air inlet slots or ventilation grilles for combustion air.
The motor features permanently lubricated ball bearings and requires no routine oiling mainte-
nance.
IMPORTANT: Check the burner flame seasonally. Aproper NATURAL gas flame will appear blue
at the burner face with orange and yellow tips. Aproper PROPANE gas flame will appear blue at
the burner face with yellow tips. If the flame is too rich, it will appear billowy and yellow with hazy
tips. If too lean, it will appear short and all blue. If the flame does not appear proper,
CONT ACT A
QUALIFIED SERVICE TECHNICIAN FOR CLEANING AND/OR READJUSTMENT.
WARNING: If any flame is observed other than pilot when the burner is on
standby, or valve operator is heard to come on before the motor reaches operating speed, immediately turn off the manual gas control and burner power. A
dangerous condition has developed and must be corrected. CONT ACT A QUALI-
FIED SERVICE TECHNICIAN FOR CLEANING READJUSTMENT AND/OR REPAIR.
WARNING: If PROPANE gas is used and the burner is located in a basement, crawl space or confining space, contact your gas supplier about
installing a GAS LEAK warning device. PROPANE gas is heavier than air and
can settle in low areas or confined spaces. This would create a danger of
explosion or fire. If you suspect a gas leak, follow instructions on front cover
of this manual.
XI Combination
Gas Valve
Maintenance
Page 11
1. TURN (DEPRESS) MANUAL GAS COCK KNOB ON COMBINATION VALVE TO OFF.
2. TURN BURNER POWER ON. SET THERMOSTAT OR OPERATING CONTROL TO
CALL FOR HEAT. LET MOTOR RUN 5 MINUTES TO PURGE COMBUSTION
CHAMBER AND CHIMNEY.
3. SET OPERATING CONTROL TO OFF OR THERMOSTAT BELOW ROOM
TEMPERATURE.
4. TURN MANUAL GAS COCK KNOB ON COMBINATION VALVE TO PILOT.
DEPRESS KNOB, OR RED BUTTON IF SO EQUIPPED, AND HOLD.
5. PUSH PIEZO IGNITOR BUTTON SEVERAL TIMES TO LIGHT THE PILOT.
6. AFTER ONE MINUTE, RELEASE MANUAL GAS COCK KNOB ON COMBINATION
VALVE, OR RED BUTTON IF SO EQUIPPED, AND TURN TO ON.
7. ADJUST THERMOSTAT OR OPERATING CONTROLTO DESIRED SETTING.
TO SHUT OFF
1. TURN (DEPRESS) MANUAL GAS COCK KNOB ON COMBINATION VALVE TO OFF.
2. TURN BURNER POWER OFF.
SHOULD OVERHEATING OF THE GAS UTILIZATION EQUIPMENT OCCUR:
1. SHUT OFF THE MAIN MANUAL SHUT-OFF VALVE TO THE EQUIPMENT.
2. DO NOT SHUT OFF THE POWER SWITCH TO THE ECONOMITE BURNER, OR THE
EQUIPMENT PUMP OR BLOWER.
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 ORDER LIST-
ED.
A. Manual Gas Cock Knob on Combination Valve, or red button if so equipped, is not
depressed in the PILOT position.
B. Main Manual Shut-Off Valve is not in open position.
C. Air in pilot gas line (See Section VIII Initial Start-up/Adjustment).
D. High or low pilot flame gas pressure (See Section IX Venturi Casting and Pilot).
E. Clogged pilot orifice(s) (See Section IX Venturi Casting and Pilot).
F. Defective ignitor, ignitor wires, spark rod or improper spark gap (See Figure 8).
G.Excessively high or negative draft condition (See Section I Ventilation and Section IV
Chimney, Vent Connector and Draft Control).
A. Excessively high or negative draft condition (See Section I Ventilation and Section IV
Chimney, Vent Connector and Draft Control).
B. High or low pilot flame gas pressure ( See Section IX Venturi Casting and Pilot).
C. Burner tube extends into combustion chamber (See Section III Combustion Chamber).
D. Lint or dust in pilot (See Section IX Venturi Casting and Pilot).
E. Clogged pilot orifice(s) (See Section IX Venturi Casting and Pilot).
F. Defective thermocouple (See Section IX Venturi Casting and Pilot).
G.Defective pilotstat safety control (See Section IX Venturi Casting and Pilot).
H. Clogged pilot filter in Combination Valve; entire valve must be replaced.
A. Confirm 120V between strip terminals 1 and 2 and verify the circuit polarity and electrical
ground between strip terminal 1 and burner chassis metal.
B. Check 24V* operating control circuit;
1.Between left strip terminal T and GND.
a.No voltage, transformer defective.
b.Very low voltage*, circuit overloaded or transformer defective.
2.Between right strip terminal T and GND.
No voltage, circuit between T and T is open.
C. Confirm 120V between strip terminal 2 and motor relay terminal 4
:
1.No voltage, motor relay is defective.
2.Voltage present, motor is defective.
11
Lighting Instructions
Trouble Chart
I. Pilot Will Not Light
II. Pilot Goes Out
Frequently
III. Motor Will Not Run
Page 12
A. Manual Gas Cock Knob on Combination Valve not in ON position.
B. Check for 24V* between blower interlock switch terminal NC and GND;
1.If no voltage, motor interlock switch or centrifugal actuator is defective. (See Section X
Blower Assembly).
2.If voltage is present, valve operator is defective; entire valve must be replaced.
A. Low manifold gas pressure.
B. Main gas spud orifice too small.
C. Primary air adjustment open too far.
A. High manifold gas pressure.
B. Main gas spud orifice too large.
C. Primary air adjustment closed too far.
D. Dirty Blower Wheel
A. Electric Valve Operator(s) of Combination Valve is defective and entire valve must be
replaced.
* Normal low voltage:
Motor running-24V minimum
Combination Valve energized-21V minimum.
** IMPORTANT: If changes are made in the main spud orifice size manifold gas pressure or primary air adjustment, change the installation data tag accordingly.
12
IV. Motor Runs
Continuously, Pilot is On,
But No Main Flame
V. Short Flame**
VI. Long, Hazy Flame**
VII. Gas Fails to Shut Off
Trouble Chart Contintued
Midco International Inc. 4140 West Victoria Street - Chicago, Illinois 60646
tel 773.604.8700 fax 773.604.4070 web www.midco-intl.com email sales@midco-intl.com
201
8470 75
Printed in USA
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