Midco Economite RE4850A Quick guide

Installation and Service Instructions
Midco®International Inc.
4140 West Victoria Street
Chicago, Illinois 60646
toll free 866.705.0514
tel [phone]
fax [phone]
web www.midcointernational.com
e-mail [email protected] Quality Designed for Proven Performance Printed in USA
8471 20
In the United States, Installation must conform with local codes or,
in the absence of local codes, with Installation of the National
Fuel Gas Code, ANSI Z223.1-latest edition, from the American
National Standard Institute. Further reference should be made
to the recommendation of your fuel supplier.
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 1B-149.
Further reference should be made to the recommendation of
your fuel supplier.
WARNING: Additions, changes, conversions,
and service must be performed by an authorized MIDCO
representative, service agency, or the fuel supplier. Use only
MIDCO specified and approved parts.
INSTALLER: Inform and demonstrate to the user the correct
operation and maintenance of the 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. Affix this manual and associated
literature adjacent to the 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
and associated literature is required, contact a qualified
service agency. DO NOT ATTEMPT REPAIRS. An inadvertent
service error could result in a dangerous condition.
!
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.
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 phone your gas supplier from another
building. Follow the gas supplier’s instructions. If
you cannot reach your gas supplier call the fire
department.
Installation and service must be performed by a qualified
installer, service agency or the gas supplier.
BURNER MODEL: ___________________________________
BILL OF MATERIAL
NUMBER: ___________________________________
SERIAL NUMBER #: ___________________________________
WIRING DIAGRAM: ___________________________________
FOR SERVICE CONTACT
Name: ____________________________________________
Address: ____________________________________________
____________________________________________
Phone: ____________________________________________
Date of Installation: ___________________________________
AVOID ERROR IN PARTS SELECTION. When ordering use complete MIDCO
Part Number and Description. Furnish Burner Model Number, Bill of Material
Number and Serial Number (if available) from the specification plate found on the
product.
IMPORTANT: Availability of parts as well as specifications are subject to change
without notice. Please consult factory for item availability.
SAFETY INFORMATION TERMS: The following terms are used to identify hazards, safety precaution of special notations
and have standard meanings throughout this manual. They are printed in all capital letters using a bold type face as shown
below, and preceded by the exclamation mark symbol. 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.
!
!
822
Economite
RE4850A / RE4400
Gas Burners
US
C
LISTED
L
U
®

2Midco International Inc. 8471 20
Part 1 Specifications
The ECONOMITE Model RE4850A and RE4400 burners with intermittent and interrupted spark
ignited pilot are adaptable to most gas utilization equipment, including gravity and forced circulation
furnaces and boilers. They are particularly recommended for firing horizontal or downdraft
equipment since no draft is required to maintain a pilot. Power burner design makes them perfectly
suited for oil burner replacement, including rooftop and industrial applications.
AIR DELIVERY (Approximate Air Delivery at Zero Draft)
RE4850A and RE4400 .................. 125 SCFM
2
FIRING RATE (NATURAL OR PROPANE) 3
RE4850A RE4400
MAXIMUM MBH
4850 400
MINIMUM MBH
4280 132
GAS SUPPLY PRESSURE REQUIRED
NATURAL ...................................... 7.0″to 14.0″W.C.
PROPANE ..................................... 5.0″TO 14.0″W.C.
TUBE DIAMETER.............................................. 4”
TUBE LENGTH.................................................. 9”
RECOMMENDED COMBUSTION CHAMBER SIZE (AT MAX. BTU/HR)
RE4850A RE4400
WIDTH 15″10″
LENGTH 30″16.5″
ELECTRICAL SUPPLY............................. 120 Volts / 60 Hertz
FLAME SAFETY....Electronic Flame Safety with Spark Ignited Pilot and 100% Shut-Off
TABLE 1: Burner Specifications
1. Standard burners are shipped as Natural gas models. Contact your Midco dealer for PROPANE
gas burners.
2. SCFM = Standard Cubic Feet / Minute.
3. All Ratings Based on 1000 BTU/Cu. Ft. NATURAL. Derate burner for altitude over 2,000 feet by
4% for each 1,000 feet above sea level.
4. 1 MBH = 1,000 BTU/hr.
CAUTION: The ECONOMITE Models RE4850A and RE4400 Burners are 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 heating plant
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 heating plant is located in a tight or separate
room, ventilation to an open area as described above will be required. Install two permanently open
grills, 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 heating plant 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, provisions must be
made for an outside air supply near the heating appliance area. Install permanently open grills sized
at not less than one square inch free area per 4,000 BTU of burner input. When ventilating through
horizontal ducts, grills 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 1-B149.1 or .2 and/or local
codes.
__________________________________________
!
I Ventilation
Part 1 Installation
Specifications 1

Midco International Inc. 3
8471 20
III Combustion
Chamber
Part 1 Installation
II Preparation of
the Gas Utilization
Equipment
Clean the gas utilization equipment combustion chamber, heat exchanger interior, and flue
connections. Remove all adhering tars, scale, dirt and soot. Inspect for actual or potential leaks.
Cement all joints, including those in the heating appliance base and around the 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. 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
existing chamber liner can be used, if in good condition.
In the case of wet base boilers, where the entire firing chamber is comprised of heat exchange
surfaces and no 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 firing chamber is unusually
short, in order to avoid excess flame contact on the heat exchanger walls or flueways.
If a built up chamber liner is required, use 2,300°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 opening with refractory material. 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 chamber
proper; it must be set at least 1″short of the inside surface because high combustion chamber
temperatures will cause premature pilot, electrode, burner tube and sleeve deterioration.
WARNING: BURNER MUST BE MOUNTED IN ORIENTATION SHOWN IN FIGURES 1A
AND 1B. 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 that the main burner and pilot ports are free of
foreign materials, and also that the spark electrode assembly has not been damaged or displaced.
See Figures 6A and 6B.
__________________________________________
!
!
Figure 1A -
Dry Base Boiler with Combustion
Chamber Liner (Warm Air Furnace
Construction is Similar)
Figure 1B -
Wet Base Boiler with Unlined
Combustion Chamber

4Midco International Inc. 8471 20
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 NFPA, ANSI Z223.1 latest edition.
WARNING: The vent connector shall not be connected to a chimney already venting solid
fuel burning equipment, an incinerator or an open fireplace.
The Vent Connector shall be made of non-combustible, corrosion 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 the chimney and a single gas
utilization equipment shall not exceed 75% of the the height of the chimney above the connector, or
100% if the Vent Connector is insulated.
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 or 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 sheet-metal 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.
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 (see Figures 3 and 4). 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.
Gas utilization equipment requiring controlled draft may be equipped with a listed double acting
barometric draft regulator, if approved by local codes (see Figure 4).
A device which will automatically shut offgas to the burner in the event of sustained backdraft is
required. It shall be of the listed manual reset type and installed and adjusted by a qualified service
technician in accordance with the manufacturer’s instructions.
Refer to gas utilization equipment manufacturer for recommended vent connection requirements.
__________________________________________
IV Chimney, Vent
Connector and
Draft Control
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!
Part 1 Installation

Midco International Inc. 5
8471 20
Figure 2A: Wiring Diagram
Figure 2B: Siemens Wiring Diagram
SAFETY &
OPERATING
CONTROLS
5
4
4
L2
G
3
F
L2
L1
6 KV
PILOT GAS VALVE
10
9
REDUNDANT VALVE
10
9
88
OPTIONAL VENT VALVE
BLOWER AIR
SWITCH
7
6
7
FIRING RATE
CONTROLLER
R
W
B
OPITIONAL HI-LO GAS PRESSURE
SWITCH IF NOT USED JUMPER
L1 TO 5
ALTERNATE WIRING FOR FULL-MOD
CONTROL 135 OHMS
IGNITION TRANSFORMER
3(C)
2 (NO)
2 (NO)
1 (NC)
3(C)
1 (NC)
NN
GG (1)C(2)NO
(3)NC
NEUTRAL
120/1/60
HOT
MBLOWER MOTOR
1/2 HP MAX.
SPARK ROD
HI-LO
CONTROLLER
34
MAIN GAS VALVE
24V
TT
OPTIONAL ALARM
3
FLAME ROD
OFF ON
R
W
B
5
6
DASHED WIRING AND
COMPONENTS BY INSTALLER
OPTIONAL WIRING AND
COMPONENTS BY MIDCO
ENCIRCLED:
FLAME SAFEGUARD
SOLID ROUND:
BURNER STRIP
OPEN ROUND:
COMPONENT
F
LEGEND
SOLID WIRING AND
COMPONENTS BY MIDCO
LIGHT (LOCATED IN
GAS SWITCH ENCLOSURE)
5
ALTERNATE WIRING FOR
FULL-MOD CONTROL 4-20 MA
3 (l+)
5 (c)
MODULATING
CONTROLLER
4-20MA
OUTPUT
-
+
9L2
24V
TT
W
G
SPARK ROD
IGNITION
TRANSFORMER
FLAME SENSE ROD
DISPLAY
OFF - Standby, waiting for
call for heat
P24 - Fan motor on, Actuator opens
in high-fire
P30 - Prepurging
P36 - Actuator closes to ignition
position
P40 - Ignition, gas valve on
P44 - End of safety time
oP - Operation, modulating
operation
Loc - Lockout
P74 - Post purging
MAIN VALVE
PILOT GAS VALVE
OPTIONAL ALARM
BK
L2
BK
W
R
R
R
R/BK
JUMPER
FUSE BK
R/BK
JUMPER
R/BK
JUMPER
X65
12
X66
123
X76
1234
X56
1234
X3-04
132 45
X2-03
23
1
SIEMENS
LME71.000A1
PME71.111A1
2
X2-01
3
14
32
1
X2-02 X6-03
132
1
X9-04
3
X5-01
2123
X3-02
2
1
X5-03
1234
X10-06
12
3
X10-05
2
145
X4-02
23
1
X7-04X7-01
132 4
3
2
1
R
R
G
BK
R
BL
BK
G
P38 - Preignition, Sparking
oP - Present output, %
FL - Flame current, %
L1
L2
G
SAFETY & OPERATING
CONTROLS
ON/OFF
L1
AS
C
NC
NO
LEGEND
SOLID ROUND: TERMINAL
BLOCK STRIP
SOLID: WIRING AND
COMPONENTS BY MIDCO
DASHED: WIRING AND
COMPONENTS BY INSTALLER
3
JUMPER NOTE: IF CIRCUIT IS USED;
REMOVE JUMPER
OPEN ROUND: COMPONENT
TERMINAL
DASHED SMALL: SUPPLIED BY
MIDCO, INSTALLED BY OTHERS
FUSE 5-20mm 6.3A SLOW BLOW FUSE
WIRE NUT
NEUTRAL
120/1/60
HOT
G
L2
L1
GROUND G
W
BK
M
BLOWER
MOTOR
W
BK
V Electrical
Part 1 Installation

6Midco International Inc. 8471 20
Part 1 Installation
Figure 3: Recommended Locations for Draft Hood
Installation wiring and grounding to 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 gage for line voltage wiring. Hook up to a dedicated line with an
on-offdisconnect switch and a minimum 10 Amp breaker.
The frame of the burner should be well grounded. Normally the piping and/or electric
conduit will provide sufficient grounding. However, a ground lug is located in control box 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 to strip terminal L1, neutral L2—and that the neutral
line is not subject to induced low voltage (check L2 to earth ground) from other equipment, as that
can cause the primary safety control to malfunction.
Each installation must include suitable limit control(s). Existing oil burner combination operating and
limit controls are normally NOT SUITABLE for gas burner use.
Connect motors used on forced air furnace fans or boiler pumps to a combination limit control and
switch.
CAUTION: Label all wires prior to disconnection when servicing controls. Wiring
errors can cause improper and dangerous operation. Verify proper operation after servicing.
__________________________________________
V Electrical
Continued
!

Midco International Inc. 7
8471 20
Part 1 Installation
CAUTION: The available gas pressure should be within the limits shown in
SPECIFICATIONS section. Excessive pressure may damage electric valves, regulators and
manual valves. If the supply pressure exceeds the 14.0″W.C. maximum, a suitable high
pressure regulator must be installed between the Main Manual Shut-OffValve and burner
shut-offvalve as shown in Figure 5.
Figure 4: Location for Barometric Draft Regulators
Note: Figures 3 and 4 : Copyright by American Gas Association.
Used by permission of the copyright holder.
The burner gas supply piping should branch offfrom 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 Figure 5.
Use pipe joint compound approved for use with Liquid Petroleum Gases.
Piping must also comply with local codes.
To obtain the maximum firing rate of the burner, the gas supply piping must be sized to provide a
minimum of 7.0″W.C. pressure to the inlet of the upstream automatic safety shutoffvalve when the
burner and all other gas utilization equipment are on. The pilot regulator can be mounted in any
position. The main regulator, if equipped, should be mounted upright and in a horizontal run of pipe.
CAUTION: Because it is difficult to accurately control pressure during supply pipe
leak testing, it is recommended that all low pressure (14.0″W.C. max.) components, both
main and pilot, be disconnected during testing. Exposing low pressure regulators and
valves, including manual valves, to pressures over 1/2 PSIG (14.0″W.C.) will cause damage
and void all warranties.
VI Piping
!
CORRECT LOCATIONS
INCORRECT LOCATIONS
!

8Midco International Inc. 8471 20
Part 1 Installation
VI Piping
Continued
RE4850 UL,
Valve Train Assembly
RE4400 UL,
Valve Train Assembly
120VAC
Figure 5: Piping diagram - RE4400 and RE4850A
AIR PRESSURE
SWITCH
PILOT
REGULATOR
PILOT
PRESSURE
TAP (LOCATED
ON AUTOMATIC
PILOT VALVE)
SUPPLY GAS
PRESSURE
TAP
MAXIMUM INLET
PRESSURE 14"W.C.
AUTOMATIC SAFETY
SHUT-OFF VALVES
MANIFOLD
PRESSURE TAP**
SIGHT
GLASS SHUTTER
SHAFT
IGNITION
CONTROL
MODULE
DETAIL "A"
PILOT GAS ORIFICE
(LOCATED INSIDE TEE)
BLOWER MOTOR
PILOT AIR
ORIFICE (LOCATED
INSIDE TEE)
SEDIMENT TRAP
(SUPPLIED BY OTHERS)
MAIN MANUAL
SHUT-OFF
VALVE AND SUPPLY
PIPING ( SUPPLIED
BY INSTALLER)
DETAIL "A"
MAIN GAS
REGULATOR
AUTOMATIC
PILOT VALVE
* REQUIRED FOR APPLICATIONS
EXCEEDING 14"W.C. PRESSURE
HIGH PRESSURE REGULATOR*
(SUPPLIED BY OTHERS)
BURNER SHUT-OFF VALVE
** ORIFICES LOCATED IN TEE ASSEMBLY
AIR PRESSURE
SWITCH
PILOT
REGULATOR
PILOT
PRESSURE
TAP (LOCATED ON
AUTOMATIC
PILOT VALVE)
SUPPLY
GAS
PRESSURE
TAP
MAXIMUM INLET
PRESSURE 14"W.C.
AUTOMATIC SAFETY
SHUT-OFF VALVE
MANIFOLD
PRESSURE TAP **
SIGHT
GLASS SHUTTER
SHAFT
IGNITION
CONTROL
MODULE
DETAIL "A"
PILOT GAS ORIFICE
(LOCATED INSIDE TEE)
BLOWER MOTOR
PILOT AIR
ORIFICE
(LOCATED
INSIDE TEE)
SEDIMENT TRAP
(SUPPLIED BY OTHERS)
MAIN MANUAL
SHUT-OFF
VALVE AND SUPPLY
PIPING ( SUPPLIED
BY INSTALLER)
AUTOMATIC
PILOT VALVE
DETAIL "A"
HIGH PRESSURE REGULATOR*
(SUPPLIED BY OTHERS) * REQUIRED FOR APPLICATIONS
EXCEEDING 14" W.C. PRESSURE
AUTOMATIC SAFETY
SHUT-OFF VALVE
WITH REGULATOR
BURNER SHUT-OFF VALVE
** ORIFICES LOCATED IN TEE ASSEMBLY

Midco International Inc. 9
8471 20
Part 1 Installation
Pipe Type Approximate Capacity - MBH
Size of Gas Pipe Length
10 20 40 75 100
3/4 Natural 200 150
3/4 Propane 590 400 275 190 160
1 Natural 400 275 200 150
1 Propane 1075 730 500 360 300
1-1/4 Natural 900 600 450 325 275
1-1/4 Propane 1040 750 630
1-1/2 Natural 900 650 475 400
1-1/2 Propane 975
VI Piping
Continued
Capacities shown are for a total
pressure drop of 0.3″W.C. For
0.5″W.C. pressure drop, multiply
capacity shown by 1.3. Propane
capacities shown are for a total
pressure drop of 0.5″W.C. For
higher permissible pressure drops,
consult your gas supplier.
Table 2: Schedule 40 NPT
Pipe-Capacity Chart
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 limitation, be sure to carry out the general
arrangement shown in Figure 5.
When the burner is installed in the vestibule of jacketed equipment, it is recommended that the
Automatic Safety Shut-OffValves be left adjacent to the burner within the vestibule and the Main
Manual Shut-OffValve be installed outside.
Run full size pipe or tubing from regulator vent openings to outside of building. Provide no traps in
the vent lines and terminate away from all doors and windows; also make provisions for keeping rain
and foreign objects from entering the vent piping.
When high supply gas pressure is encountered, as in the case in many industrial plants, the gas
line size can be reduced to allow for a greater pressure drop; however, the size must be sufficient to
deliver burner rating pressure.
CAUTION: High gas pressure supply lines require the proper pressure reducing
regulators. Install two separate high pressure regulators of the Tight Shut-Offtype upstream
of the low pressure regulators. One sized for main gas input, and one suitable for the
minimum flow regulating capacity of the pilot.
The high pressure regulators must be adjustable to 14″W.C. outlet pressure.
When the gas supply line is about to be put into service it must be tested to insure that it is gas tight.
Use air or inert gas under pressure and test with soap and water or to locate leaks.
Before gas is turned onto the system, a check must be made to see that there are no open fittings
and to make sure the burner main and pilot manual valves are closed.
After checking for leaks, purge the gas line up to the burner inlet. Purging the air from the gas supply
line at this step will expedite the first light-off.
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.
__________________________________________
Burners are approved for use with NATURAL gas or PROPANE gas and should be used only with
the gas specified on the rating plate.
The gas input should be set at the heating rate determined by the building heat loss and/or heating
plant survey, but not exceeding the rated maximum input of the gas utilization equipment or
Economite burner.
__________________________________________
!
!
VII Main Gas
Input Selection

10 Midco International Inc. 8471 20
Part 1 Installation
WARNING: Ignition is automatic. Make spark observations into combustion
chamber only with Main and Pilot Manual Shut-OffValves closed. Confirm that gas utilization
equipment does not contain any accumulated gases. Purge as described in step 3 below.
CAUTION: Cover plates, guards, and enclosures must be maintained in place at all
times except during maintenance and service.
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 first light-off.
IMPORTANT: Purge outside the building. Do not purge into the gas utilization equipment.
Natural Gas / Propane Gas Orifice Size and Pressure Settings
RE4850A Natural Gas Propane Gas
Input Orifice Manifold Orifice Manifold
MBTU/ Size Letter Pressure Size Letter Pressure
HR 1(Inches) Stamp (″W.C) (Inches) Stamp (″W.C)
850 No Orifice - 3.5 0.688 I 2.4
800 No Orifice - 3.1 0.563 H 2.5
750 No Orifice - 2.7 0.5 G 2.7
700 0.688 I 2.8 0.422 F 2.8
650 0.688 I 2.4 0.422 F 2.4
600 0.563 H 2.8 0.358 J 3.9
550 0.5 G 3.15 0.358 J 3.3
500 0.5 G 2.4 0.358 J 2.7
450* 0.422 F 2.6 0.358 J 2.2
400 0.358 J 4.3 0.29 B 3.3
280 No Orifice - 0.4 0.688 I 0.15
RE4400
400 No Orifice - 4.3 0.358 J 2.8
350 No Orifice - 3.3 0.29 B 3.6
300 No Orifice - 2.4 0.261 C 3.1
250* 0.358 J 2.9 0.219 E 3.2
200 0.29 B 2.8 0.219 E 2.1
132 No Orifice - 0.6 0.358 J 0.3
Table 3: Capacity and Preliminary Gas Settings
DATA FOR TABLES IS APPROXIMATE AND BASED ON “0” OVERFIRE PRESSURE AT SEA LEVEL
1. Adjust the main regulator to vary the manifold gas pressure and burner input within the range shown.
Do not exceed pressure as listed in Table 3, under any circumstances. Use combustion readings (CO or
O2) and a flow meter to determine exact inputs.*Orifice Size and approximate manifold gas pressure
setting: as shipped. Air shutters are set at full open.
NOTE: For LP Conversion kit contact the factory
3. To purge the gas utilization equipment and chimney of any accumulated gases, turn main Manual
Gas Cock OFF, close Pilot Manual Shut-OffValve, 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 combustion
chamber volume air changes, but not less than five minutes.
CAUTION: Make sure that the capacity range of the burner, manifold pressure, and
the preliminary combustio n air shutter setting are suitable for capacity rating of the gas
utilization equipment. Refer to Section VII and Table 3.
4. RESET the Primary Safety Control. See Section XIII.
VIII Initial
Startup
/Adjustment
!
!
!
2.4
2.
5
2.
7
2.
8
2.4
3
.
9
3
.
3
2.
7
2.
2
3
.
3
0
.1
5
2.
8
3
.
6
3
.
1
3
.
2
2.
1
0
.
3
I
H
G
F
F
J
J
J
J
B
I
J
B
C
E
E
J
0
.
688
0
.
563
0
.
5
0
.422
0
.422
0
.
358
0
.
358
0
.
358
0
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850
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7
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650
600
550
500
4
50*
4
00
2
80
4
00
350
300
2
50*
2
00
1
3
2
!

Midco International Inc. 11
8471 20
Part 1 Installation
5. Confirm that Main and Pilot Manual Shut-OffValves are open. Turn main Manual Gas Cock ON, if
equipped with this feature.
6. Turn operating control to ON or set thermostat above room temperature. After the prepurge is
complete, the pilot should ignite. Whenever the burner pilot fails to light during the ignition trial, or
if the flame is lost during the burner run and is not reestablished within the designated ignition trial
period after the prepurge, the Primary Safety Control will shut offthe Automatic Safety Shut-off
Valves and LOCK OUT. RESET the Primary Safety Control. If burner still fails to light, turn it offand
repeat from step 4 above. Then if necessary, refer to the Primary Safety Control manufacturer’s
literature provided with the power burner for more details.
WARNING: Repeated unsuccessful attempts to light 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. To make a preliminary setting of the burner input, determine the manifold gas pressure required
from Table 3 and adjust the Main Gas Pressure Regulator accordingly.
8. 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.
3600 x test dial size x BTU value
= BTU/Hr.
No. of seconds for one rev. test dial
Then divide by 1,000 for MBH value.
Example: 3600 x 1 x 1000
= 360,000 BTU/HR = 360 MBH
10
9. Check the operation of the burner; start and stop it several times with the thermostat or operating
control.
10. With the burner running, check the operation of all limit and associated controls.
11. Perform the following final adjustments for combustion and flue gas temperature. Take the flue
gas samples and temperature immediately ahead of the draft control.
A. 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.
B. Make the final setting of the combustion air shutter by checking the flue gases with an
ORSAT or similar combustion testing 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 or 12% for propane, or within the limits prescribed by
local codes.
12. Check the draft control to make sure there is no spillage of flue products into the room.
13. FILL OUT THE INSTALLATION ADJUSTMENT DATA TAG and affix to the burner or gas
utilization equipment.
NOTE: For subsequent normal starting and shut offprocedure, refer to
CONSUMER INSTRUCTIONS, located in part 3 of this manual, or to the
instruction plate mounted on the burner.
__________________________________________
VIII Initial
Startup
/Adjustment
!

12 Midco International Inc. 8471 20
Part 2 Service
DANGER: Do not tamper with the unit or controls. If trouble occurs contact
the installing contractor, service agency, or fuel supplier. See front cover.
DANGER: Be sure that the main and pilot manual Shut-OffValves are closed
and the burner power supply is turned offbefore removing any parts for service.
CAUTION: Cover plates, guards, and enclosures must be maintained in
place at all times except during maintenance and service.
__________________________________________
The pilot is of the premix, blast type. The full force of blower air is brought into the mixing
tube where the proper amount of gas is added through the pilot orifice. This mixture is
discharged through the pilot. The mixture provides the flame that contacts the flame sensing
rod and also ignites the main gas.
Gas Orifice
Diameter Approx. Pilot Gas Pressure
#54 Capacity Natural Propane
Model Wire Drill BTU/Hr. Inches W.C. Inches W.C.
RE4850A 0.055″6000
RE4400 0.055″6000 3.0″to 4.5″2.5″to 3.5″
Table 4: Pilot Specifications
CAUTION: Do not indiscriminately increase pilot orifice size. Pilot troubles are
rarely cured in this manner and new troubles may be created.
Under normal conditions, with a slight negative pressure in the combustion chamber, pilot operating
pressures should be set as indicated in Table 4.
!
!
!
IX Pilot
RE4
850
A
RE44
00
0
.
055
″
0
.
055
″
6000
6000
3
.
0
″to 4.
5
″2.
5
″to
3
.
5″
!
*NOTE:
SPARK ROD SHOULD BE CENTERED IN THE TEE
& HELD SECURELY BY THE RETAINING BUSHING.
OVER TIGHTENING OF THE RETAINING BUSHING
MAY CRACK THE CERAMIC INSULATOR.
3/8" TEE PILOT ASSEMBLY *
(PARTIAL CUT-A-WAY VIEW)
END VIEW OF CARTRIDGE
CARTRIDGE ASSEMBLY
7/16"
WINDOW
PLUG
STRAIN RELIEF
BUSHING
NYLON
INSERT
BACK PLATE
WELDMENT
3/8" PILOT
AIR TUBING
PILOT
BRACKET
SPARK ROD
ASSEMBLY
FLAME SENSING
ROD BRACKET
2 REQUIRED
RETENTION PLATE
BURNER HEAD WELDMENT
FLAME SENSING ROD ASSEMBLY
3/8" TEE PILOT
ASSEMBLY
19/32"
3/8" TEE PILOT DETAIL
(NATURAL) (PROPANE)
RETENTION PLATE
.18"
13/32"
RETAINING BUSHING
SPARK ROD
ASSEMBLY
1/2" RETENTION PLATE
S
CERAMIC
INSULATOR
NOTE:
MAKE SURE THAT THE FLAME
SENSING ROD CENTER-LINE
COINCIDES WITH THE 1/2" RE-
TENTION PLATE CENTER-LINE.
Figure 6A: General Assembly for RE4400

Midco International Inc. 13
8471 20
Part 2 Service
Figure 6B: General Assembly for RE4850A
Some conditions which may require a change from the normal setting include: extremely long tubing
connections between the regulator and pilot solenoid, high negative or positive combustion chamber
pressure, actual air shutter setting and altitude extremes.
Do not subject the pilot to an inlet pressure over 14.0″W.C. See Section VI PIPING for high
pressure gas.
To adjust outlet pressure, remove the seal cap for access to the adjusting screw. Turning the screw
clockwise will increase outlet pressure, counter clockwise will decrease outlet pressure.
The spark rod is welded to a round 1/2″retention plate. The 1/2″retention plate is centered in the
3/8″Tee pilot and is positioned so the high tension voltage will arc to the inside of the 3/8″Tee pilot.
(See Figures 6A & 6B).
The flame sensing rod must be positioned as shown in Figures 6A & 6B so that the Primary Safety
Control will detect a proper flame.
Both the spark and flame rods are current carrying conductors and, along with their connecting
wires, must be kept free of contact with conductive metal parts of the burner. Rod insulators and
wire insulators should be clean, dry and free of cracks.
Rods are made from heat resistant alloys and can be expected to have a long service life. They
should be routinely inspected, however, for corrosion or loss of metal.
The pilot air tubing must be kept free of kinks or inside obstructions and must be positioned per
Figures 6A & 6B, otherwise air flow could be reduced and adversely affect the pilot flame.
__________________________________________
*NOTE: SPARK ROD SHOULD BE CENTERED IN THE TEE & HELD
SECURELY BY THE RETAINING BUSHING. OVER TIGHTENING OF
THE RETAINING BUSHING MAY CRACK THE CERAMIC INSULATOR.
3/8" TEE PILOT ASSEMBLY *
(PARTIAL CUT-A-WAY VIEW)
CARTRIDGE ASSEMBLY
NOTE:
MAKE SURE THAT THE FLAME ROD CENTER-LINE COINCIDES WITH
THE 1/2" RETENTION PLATE CENTER-LINE. VERIFY THAT THE FLAME
ROD RECESSED INSULATOR TOUCHES THE RETENTION PLATE.
RETAINING
BUSHING
13/32"
CERAMIC INSULATOR
S
END VIEW CARTRIDGE
RE4850A MODEL
GAS PORT
MODEL RE4850A
RETENTION PLATE (RE4850A ONLY)
3/8" PILOT
AIR TUBING
19/32"
3/8" TEE PILOT
ASSEMBLY
FLAME SENSING
ROD BRACKET
2 REQUIRED
SPARK ROD
ASSEMBLY
MODEL
RE4850A
ONLY
STRAIN RELIEF
BUSHING
BACK PLATE
WELDMENT
NYLON
INSERT
FLAME
SENSING
ROD
ASSEMBLY
BURNER
HEAD
WELDMENT
1/2" RETENTION PLATE
SPARK ROD
ASSEMBLY
7/16" WINDOW
PLUG
PILOT BRACKET
3/8" TEE PILOT DETAIL
(NATURAL) (PROPANE)
IX Pilot
Continued

14 Midco International Inc. 8471 20
Part 2 Service
CAUTION: BEFORE SERVICING, mark with a scribe line or measure opening of air
controlling 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 indicated 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 motor and wheel are removed as an assembly. Disconnect the motor wires from the motor
terminal strip. Disconnect the motor conduit from the motor and remove the mounting bolts.
The burner is equipped with a diaphragm type air pressure switch so as to prevent the burner from
firing if the blower wheel is not running at its operating speed. When the motor is offthere is no air
pressure present to activate the pressure switch and in turn there is no power flow to the Primary
Safety Control.
To make a specific test of the interlock circuit:
1. Turn burner power OFF.
2. Turn Manual Gas Cock OFF.
3. Disconnect the motor wire from the terminal strip to keep the motor off.
4. Turn burner power ON and set the operating control to ON or thermostat to call for heat.
Verify there is 120VAC line voltage by using a multimeter.
A. No voltage: Interlock circuit OK.
B. Voltage present: check that the switch is wired properly or check switch operation.
Replace if switch tests bad.
Figure 7: Motor / Blower Assembly
__________________________________________
DIAPHRAGM & SOLENOID GAS SAFETY VALVES
(Main and Redundant Main; Standard Construction.)
When the solenoid valve operator is electrically energized the plungers lift the valve disk offthe
valve seats, allowing gas to flow. When the current on the solenoid valve is broken the valves
close. They will normally require no service. However, dirt or foreign matter on the valve seats could
cause leakage. If leakage is detected or if the operator malfunctions replace the entire valve. After
replacement check for leakage. If the valve is removed from the piping do not use the operator
assembly as a lever to turn valve. Apply wrench on the valve body flat adjacent to pipe being
removed.
X Motor Blower
Interlock
!
MOUNTING FACE
BLOWER
WHEEL
7/16"
1/6 HP MOTOR
XI Valve Train

Midco International Inc. 15
8471 20
Part 2 Service
OPTIONAL MOTORIZED MAIN AUTOMATIC VALVE
(Employed with Redundant Solenoid Valve.)
Motorized Main On-Off, 2-Step, and Full Modulating Valves, are available on special
order. The redundant and solenoid valve may be omitted if the motorized valve includes
optional “Proof of Closure Switch”.
When the actuator is energized, hydraulic fluid is pumped from a reservoir to a metal bellows. The
bellows transfers the resulting pressure through the drive stem to open the valve. A separate spring
return drive arm operates the blower shutter.
For general service, the valve should be checked for operation. The valve actuator may be removed
from the valve body, however, do not disassemble actuator; if malfunction occurs, replace entire
actuator assembly. The valve body is also not field reparable. If leakage is detected the entire valve
body must be replaced.
__________________________________________
The RE4850A and RE4400 operate when power is applied to L1 and L2 through a safety and/or
operating control. With power applied to L1 and L2 the blower motor starts. Once the diaphragm
air flow switch proves blower operation, power is applied to the Primary Safety Control. The Primary
Safety Control provides the switching of the gas valve and ignition sequence. If the flame signal
is above 2DC micro amps the RE4850A and RE4400 will remain in operation until a safety or
operating control opens the circuit to L1 and L2. For a more thorough explanation, refer to the
Primary Safety Control manufacturer’s literature provided with the power burner. For startup
information see section VIII.
__________________________________________
WARNING: Explosion hazard. Do not use any electronic device if it gets wet. It can
malfunction and cause serious injury or death. Replace any device that has been wet.
The Primary Safety Control (such as the Honeywell RM7895A or Siemens LME7) is a low
voltage, solid state, direct spark ignition control module for gas-fired furnaces, boilers and heating
appliances. UL Listed models are only available with a prepurge timer. The Primary Safety Control
controls the gas valve, monitors the main burner flame and generates a high voltage for spark
ignition.
The Primary Safety Control uses separate electrodes for spark ignition and flame sensing. Use with
any gas control designed for DSI application that is rated at 2.0 A or less. Includes a 30 second
(minimum) delay for use with system pre-purge.
For operation characteristics, maintenance, and service procedures, refer to manufacturer’s
literature provided with burner, or contact your Primary Safety Control dealer.
__________________________________________
XI Valve Train
Continued
XII Sequence
of Operations
!
XIII Primary
Safety Control

16 Midco International Inc. 8471 20
Part 2 Service
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 manuals to identify any differences in
construction, operation, and testing. Field installed special equipment is the responsibility of the
installing contractor.
Consult the manual to identify the differences in the information.
__________________________________________
CONSUMER INSTRUCTIONS
MAINTENANCE
Keep the area around the burner clear and free of combustible material, gasoline or other flammable
liquids or vapors. Do not obstruct burner air openings or ventilation grills for combustion air.
The motor features permanently lubricated ball bearings and requires no maintenance.
WARNING: If any flame is observed when the burner is on standby, or if the ignition
spark or valve operator is heard to come on before the motor reaches operating speed,
immediately turn offthe manual gas control and burner power. A dangerous condition has
developed and must be corrected. CONTACT A QUALIFIED SERVICE TECHNICIAN FOR
CLEANING, READJUSTMENT OR REPAIR.
Check that the pilot ignition spark does not come on before the motor reaches operating speed. If it
does, the air switch is defective and must be replaced. (See Section X, Motor Blower Interlock)
LIGHTING INSTRUCTIONS
1. SET OPERATING CONTROL TO OFF OR THERMOSTAT BELOW ROOM TEMPERATURE.
2. TURN MANUAL GAS COCK ON.
3. TURN BURNER POWER ON.
4. SET OPERATING CONTROL TO ON OR THERMOSTAT TO CALL FOR HEAT.
5. IF THE PILOT FLAME IS NOT PROVEN WITHIN THE DESIGNATED IGNITION TRIAL
PERIOD. AFTER THE PRE-PURGE, THE PRIMARY SAFETY CONTROL WILL SHUT OFF
THE AUTOMATIC SAFETY SHUT-OFF VALVES AND LOCK OUT. IF THE PROOF OF FLAME
IS LOST DURING BURNER RUN AND THE PILOT IS NOT REESTABLISHED WITHIN
THE DESIGNATED IGNITION TRIAL. AFTER THE PRE-PURGE, THE PRIMARY SAFETY
CONTROL WILL SHUT OFF THE AUTOMATIC SAFETY SHUT-OFF VALVES AND LOCKOUT.
TO RESET FOR RESTART, DEENERGIZE THE CONTROL BY SETTING THE OPERATING
CONTROL TO OFF OR THERMOSTAT BELOW ROOM TEMPERATURE FOR AT LEAST 60
SECONDS.
6. REPEAT STEP 4 FOR RESTART.
TO SHUT OFF:
1. TURN MANUAL GAS COCK OFF.
2. TURN BURNER POWER OFF.
SHOULD OVERHEATING OF THE APPLIANCE OCCUR:
1. Shut offthe manual gas control to the appliance.
2. Do not shut offthe electrical supply power to the blower.
__________________________________________
XIV Special
Equipment (OEM
Version)
Part 3 Maintenance
P
P
a
a
r
r
r
t
t
3
3
3
M
M
M
M
a
a
i
i
n
n
t
e
e
n
n
a
a
n
n
n
c
c
c
e
e
e
Maintenance
Consumer
Intructions
!

Midco International Inc. 17
8471 20
Trouble Chart
TROUBLE CHART
Make sure the thermostat and operating controls are calling for heat.
CAUTION: If a test indicates an electrical component may be defective, before
replacing it, make sure that its associated wiring is not at fault.
ELECTRICAL AND FLAME CHECKS MUST BE MADE IN THE ORDER LISTED BELOW.
I. MOTOR WILL NOT RUN
A. Confirm 120V between strip terminals L1 and L2 and verify the circuit polarity and
electrical ground between strip terminal L1 and burner Ground.
B. Check for 120V between strip terminals L1 and L2.
1. No voltage, open circuit in operating controls.
2. Voltage present, motor is defective.
II. MOTOR RUNS CONTINUOUSLY, PILOT WILL NOT LIGHT
A. Confirm that ALL Main Manual Shut-OffValves are in the ON position.
B. After the pre-purge, if the pilot flame is not proven within the pilot flame re-establishing
period, or if the proof of flame is lost during the burner run and the pilot is not re-established
after the pre-purge, the Primary Safety Control will lock out. To reset the Primary Safety Control
for restart, reset alarm button.
C. Clogged pilot orifice.
D. Pilot regulator mis-adjusted or defective.
E. Defective spark electrode or Primary Safety Control.
F. Defective high tension wire.
G. Wrong pilot orifice.
H. Defective pilot valve.
I. Pilot air tube clogged.
J. Incorrect spark gap.
K. Pilot regulator vent clogged.
L. Defective blower air switch.
M. Slow motor.
III. PILOT LIGHTS, NO MAIN FLAME
A. Poor pilot flame adjustment.
B. Clogged pilot air tube.
C. Defective flame sensing rod or wire.
D. Flame sensing rod mis-located.
E. Defective Primary Safety Control.
F. Defective main gas valve.
G. Low gas pressure.
H. Grossly mis-adjusted main gas and air.
__________________________________________
Trouble Chart
!
I Motor Will
Not Run or Motor
Runs in Repeated
Cycles
II Motor Runs
Continuously,
But No Flame
III Pilot Lights,
No Main Flame

Midco®International Inc. - 4140 West Victoria Street - Chicago, Illinois 60646 - toll free: 866 705 0514
tel: [phone] - fax: [phone] - web: www.midcointernational.com - e-mail: [email protected]
18
Printed in USA
8471 20
822
Economite RE4850A / RE4400 Installation Manual