Midco Blue Flame Series 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 34
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HMA 2 &
HMA 2A
DIRECT FIRED MAKE-UP AIR BURNERS are used in
industrial and commercial applications to maintain the
desired environmental temperatures required by critical
processes i.e. health purposes, production systems,
quality control, comfort and loss prevention where it
is necessary or required to exhaust large amounts of
conditioned air.
Make-up Air Systems used as stand alone heating
systems or operating in combination with central heating
plants systems can be cost effective in three ways: 1)
reducing the initial expenditures, 2) tempering incoming
air which may extend the life of expensive central heating
plants and 3) reducing excessive equipment cycling or
premature component failures due to increased heating
demands.
Our innovative two stage combustion burner is not just a
modification or improvement of the old, but a completely
new approach to direct-fired combustion. The two-stage
combustion improves control of the flame process, meets
or exceeds the new ANSI Standards while outperforming
the competition. By incorporating two separate flames
within the burner combustion zone, the flame is more
stable, shorter and cleaner, permitting the reduction of
emissions levels and allowing for higher temperature rise
and higher tolerance to varying conditions when placed in
the profile opening.
The Blue Flame Series Features and Benefits
Reduced NO2and CO Emissions: Lower emissions
levels that pass the ANSI Z83.4, Z83.18 and Z83.25 standards.
Higher Temperature Rise: The two stage combustion
process lowers NO2emissions which is the limiting factor in
temperature rise.
Increased Capacity: Up to 750,000 BTU’S per foot. (Higher
BTU levels can be achieved if ANSI Z83 Standards for CO and
NO2emissions are not of a concern. Process heaters can fire
up to 1,000,000 BTU’S a foot or more.)
Increased Differential Pressure Drop and Higher Velocities:
HMA 2 & 2A burners can operate as low as 0.05″to 1.4″W.C.
differential pressure range or in air velocity as low as 800 fpm to
4000 fpm.
Flame Stability: Two stage combustion provides better flame
stability and emission control, allowing for a shorter flame and
easier profile configuration.
Reduced Inventory Costs - HMA 2A: Single burner casting
can be fired with natural, propane or butane gas 1, reducing
burner inventory.
Reduced Shipping Costs: A smaller, lighter casting than the
competition’s, can lower your freight costs.
Turndown: 30-1 turndown can be achieved with proper
modulating controls and valves. (Higher turndown possible
depending on equipment design.)
Emission performance is application specific and may vary.
1 Consult Midco for applications using butane fuels.
Direct-Fired Gas Burners
MADE in the USA
1219

2Midco International Inc. 8471 34
Specifications
Specifications
*Firing Rate .............................................................. Up to 750,000 Btu/hr/ft
750,000+ Contact Midco
Burner Manifold Pressure
Natural Gas ................................................. 4.2 to 8 inch W.C.
Propane Gas .............................................. 1.6 to 3 inch W.C.
Pilot Capacity ............................................................ 12,000 Btu/hr
Pilot Manifold Gas Pressure
Natural Gas ................................................. 3.5 inch W.C.
Propane Gas .............................................. 2.0 inch W.C. **
Pressure Drop Across the Burner ............................ 0.05 to 1.4 inch W.C.
Air Velocity Across the Burner ................................... 800 to 4,000 FPM
Burner Turn-down Ratio ........................................... 30 to 1 (based on Btu / ft)
Flame Length ....................See page 5 for flame length Chart 5, and Tables 2 & 3
* Firing rate is dependent on the pressure across the burner. Please see the included
charts for recommended burner sizing.
** Using a natural gas pilot on propane.
*** See Page 14, Figure 6 for burner configuration reference.
**** See Page 15, Figure 7 for pilot configuration reference
Midco International Inc. reserves the right to change the construction or configuration of its products at any time.
All information is based on laboratory testing. Different unit size and/or configurations may affect data.
Cast Iron (CI) Aluminum (AL)
*** Burner Configurations HMA 2 HMA 2A HMA 2 HMA 2A
2″Straight Section (2A only) - - - 1020810
6″Straight Section 1050700 1050710 1050800 1050810
6″Straight Section with Back Inlet 1230700 1230710 1230800 1230810
12″Straight Section 1010700 1010710 1010800 1010810
12″Straight Section with Back Inlet 1060700 1060710 1060800 1060810
Elbow Section 1070700 1070710 1070800 1070810
Tee Section 1080700 1080710 1080800 1080810
**** Pilot Configurations Part # Natural # Propane #
Brute Pilot Spark Rod and Flame Rod 1190850 1190950
Brute Pilot Spark Rod and UV Mount 1200350 1200450
Brute Pilot Spark Rod 1342-03
Brute Pilot Flame Rod 1360-03
(Direct) Spark Rod and Flame Rod 1190800 1190900
(Direct) Spark Rod and UV Scanner Mount 1200300 1200400
Remote Flame Rod 1220800
Remote UV 1240800
Pilot with Spark Rod only 1210800 1210900
Flame Rod (Direct Spark, Std + Brute)1360-03
Spark Rod (Direct Spark) 1342-06
Table 1 - Burner and Pilot Configurations

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HMA 2 & HMA 2A Burner Performance
Burner Performance
0.0
1.0
2.0
3.0
4.0
5.0
0 20 40 60 80 100 120
0.0
1.0
2.0
3.0
4.0
5.0
0 20406080100
120
0.0
1.0
2.0
3.0
4.0
5.0
020 40 60 80 100 120
350,000 Btu/hr/ft at 0.35" W.C. pressure drop across the burner
CO Emission
CO Emission
Temperature Rise*
Temperature Rise*
Temperature Rise*
CO (PPM)
CO (PPM) CO (PPM)
550,000 Btu/hr/ft at 0.6" W.C. pressure drop across the burner
750,000 Btu/hr/ft at 1.1" W.C. pressure drop across the burner
CO Emission
NOTE: Emission performance is
application specific and will vary
020 40 60 80 100 120
0.0
0.1
0.2
0.3
0.4
0.5
0 20406080100120
0.0
0.1
0.2
0.3
0.4
0.5
0 20406080100120
0.0
0.1
0.2
0.3
0.4
0.5
NO Emission
2
NO Emission
2
NO Emission
2
Temperature Rise*
Temperature Rise*
Temperature Rise*
NO (PPM)
2
550,000 Btu/hr/ft at 0.6" W.C. pressure drop across the burner
750,000 Btu/hr/ft at 1.1" W.C. pressure drop across the burner
NO (PPM)
2NO (PPM)
2
350,000 Btu/hr/ft at 0.35" W.C. pressure drop across the burner
0.0
20
40
60
80
100
0100000 200000 300000 400000 500000 600000
Heat Input (Btu/hr/ft)
NO (PPM at 3% O )
x
2
NO Emissions Profile
x
90
70
50
30
10
.45 Delta P
.64 Delta P
.85 Delta P
Chart 1 - CO and NO2Emissions Data
* For higher temperature rise contact
Midco Engineering Department.

4Midco International Inc. 8471 34
Burner Performance
Continued
___________________________________
HMA 2 & HMA 2A Burner Performance
300,000
400,000
500,000
600,000
700,000
800,000
0.20 0.40 0.60 0.80 1.00 1.20
Pressure Drop across the Burner ("W.C.)
BTU/hr/ft
Propane Gas
Natural Gas
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
100,000 200,000 300,000 400,000 500,000 600,000 700,000
BTU/hr/ft
Propane Gas
Natural Gas
(Manifold)
Fuel Gas Pressure ("W.C.)
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
0.20 0.40 0.60 0.80 1.00 1.20
Profile Velocity (SFPM)
0.55
Chart 4 - Pressure Across the Burner verses Profile Velocity
Chart 3- BTU’s verses Gas Pressure ( ″W.C.)
Chart 2- BTU’s verses Pressure Drop

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- Velocity and pressure drop figures shown in Table 2 apply to standard design conditions.
However, these conditions apply only when air enters the heater at 70°and requires little or no heat.
In practice with the burner operating, these figures will vary, especially with inlet air at the minimum
design temperature. This is because the blower handles a constant volume of air regardless
of its temperature. When the air is heated expansion takes place ahead of the blower and just
downstream of the burner. It follows therefore that when the air is being heated a lesser volume
enters the heater, causing a reduction, both in velocity and pressure drop at the burner. Table
2 shows the variation for minimum temperature air entry and with full input to the burner. Flame
lengths given in Table 2 and Chart 5 apply to conditions shown in Table 2.
Air flow at burner Approximate length of flame
based on 70°(std) Burner Capacity (per foot) projecting beyond end of
blower rating Natural & Propane Gas burner and profile plate *
Design
Design Pressure Max. Min.
velocity drop capacity capacity Turn 550,000 650,000 750,000
FPM ″W.C Btu/Hr Btu/Hr Down per ft per ft per ft
2900 .7″550,000 19,000 29:1 13″16″20″
2550
.55″550,000 18,000 30:1 15″19″22″
(ideal)
2300 .45″550,000 17,000 32:1 17″20″24″
Reduce capacity 4% per each 1000 ft altitude over 2000 ft.
* Flame lengths are given to the end of the main mass of flame, excluding any isolated
wisps or flashes, and for normal operations ie. with cold inlet air (design minimum)
Velocity Pressure Air Actual cold Actual cold
at burner drop at temp. air velocity air pressure
(from Table 1) burner rise at burner drop at burner
2900 fpm .7″W.C. 75°2500 fpm .52″W.C.
100°2350 fpm .46″W.C.
2550 fpm .55″W.C. 75°2200 fpm .41″W.C.
100°2075 fpm .36″W.C.
2300 fpm .45″W.C. 75°1975 fpm .33″W.C.
100°1850 fpm .29″W.C.
EXAMPLE: A heater rated for 100°rise, 70°outlet temperature at a design velocity of 2550 fpm
and a design pressure drop of .55″W.C., will in actual operation pass 2075 fpm over
the burner with a .36″W.C. drop when air enters at -30°.
HMA 2 & HMA 2A flame length as a function of pressure drop and firing rate applies to push and pull
through systems using 100% fresh standard air.
Air Flow Variations
Due to Heating in a
Pull-Thru System
Installation
Table 2 - Design Data for Pull-Thru System
Table 3 - Air Flow Variations for Pull-Thru System
35
0
10
15
20
25
30
5
1.20.2 0.4 0.6 0.8 10
HMA 2 & HMA 2A Flame Length
750,000 Btu/ft
650,000 Btu/ft
550,000 Btu/ft
Pressure Drop ( " W.C.)
Flame Length ( inches )
Chart 5 - HMA 2 & 2A Flame Length

6Midco International Inc. 8471 34
1. Required BTU:
BTU/hr = Blower SCFM x Desired Temp. Rise x 1.08 / .92
2. Required Burner Length:
Feet of burner = [Required BTU/hr]÷[Burner Firing Rate (BTU/hr/ft)]
The Burner Firing Rate should correspond to the pressure drop across the burner
shown in Chart 2.
3. Required Profile Area:
Total Burner Area = Number of burner sections x burner area
(Burner Section) Burner Area
2 inch 0.11 sq. ft.
6 inch 0.32 sq. ft.
12 inch 0.65 sq. ft.
T Section 0.77 sq. ft.
Ell Section 0.65 sq. ft.
Net Profile Area = Rated Fan (SCFM) ÷ Profile Velocity (SFPM)
The Profile Velocity can be determined from the following:
∆P is the pressure drop across the burner
Profile Area = Net Profile Area + Total Burner Area
___________________________________
Sizing the burner and the corresponding profile for a 5,000 SCFM and a 115 degrees
temperature rise.
1. Required BTU:
BTU/hr = Blower SCFM x Desired Temp. Rise x 1.08 / .92
BTU/hr =5,000 (SCFM) x 115 (∆T) x1.08 / .92 = 675,000 BTU/hr
2. Required Burner Length:
Feet of burner = [Required BTU/hr]÷[Burner Firing Rate (BTU/hr/ft)]
To determine the optimum burner length we can choose from a combination of 12
inch or 6 inch burner sections referring to Table 1. We can either fire the burner
at a rate of 675,000 BTU/hr per ft, or we can fire the burner at 450,000 BTU/hr per ft
(1.5 feet of burner). Refer to Chart 3 for the fuel pressures requirements at different
firing rates.
3. Required Profile Area:
Total Burner Area = Number of burner sections x burner area
(Burner Section) Burner Area
2 inch 0.11 sq. ft.
6 inch 0.32sq. ft.
12 inch 0.65sq. ft.
T Section 0.77sq. ft.
Ell Section 0.65sq. ft.
Total Burner Area = 1.0 (ft) x 0.65 = 0.650 ft 2
Or
Total Burner Area = 1.5 (ft) x 0.65 = 0.975 ft 2
Profile Setup
Profile Velocity 0750
945 PΔ =
.
Profile Setup Example
Installation

Midco International Inc. 7
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Installation
Net Profile Area = Rated Fan (SCFM) ÷ Profile Velocity (SFPM)
The Profile Velocity should be determined based on the burner firing rates. If we choose to fire the
burner at 675,000 BTU/hr/ft then the profile opening should be sized for a pressure drop of 0.8 ″
W.C. across the burner. If the firing rate is 450,000 BTU/hr/ft then the profile opening should be
sized for a pressure drop of 0.4 ″W.C. across the burner. The corresponding profile velocity across
the burner should be determined from Chart 4 or use the following equation.
For the 675,000 BTU/hr/ft
Net Profile Area = 5000 (SCFM) ÷ 3086 (SFPM)=1.62 ft2
For the 450,000 BTU/hr/ft
Net Profile Area = 5000 (SCFM) ÷ 2182 (SFPM)=2.29 ft2
To calculate the profile area needed for both cases:
Profile Area = Net Profile Area + Total Burner Area
For the 675,000 BTU/hr/ft
Profile Area = 1.62 + 0.650 = 2.27 ft2
For the 450,000 BTU/hr/ft
Profile Area = 2.29 + 0.975 = 3.265 ft2
To calculate the length of the profile opening add burner length to the desired clearance:
For the 675,000 BTU/hr/ft case
12 inch + 4 inch (2 inches on each side) = 16 inch (1.3 ft)
For the 450,000 BTU/hr/ft case
18 inch + 4 inch (2 inches on each side) = 22 inch (1.83 ft)
To calculate the height of the profile opening divide the profile area by the profile length:
For the 675,000 BTU/hr/ft case
2.27 ft2÷ 1.3 ft = 1.75 ft (21 inch)
For the 450,000 BTU/hr/ft case
3.265 ft2÷ 1.83 ft = 1.78 ft (21.5 inch)
1. Conversion of SCFM to Actual CFM of air
SCFM = CFM x ρ
_____
0.075
2. Air density as a function of Temperature -- ρ= 1.35 x Barometric Pressure (in Hg)
T
(out) + 460
3. Change in Standard Barometric Pressure as a function of Altitude
Barometric Pressure (in.Hg) = 29.921x (1-6.8753 x 0.000001x altitude (ft))^5.2559
4. Temperature difference -- Temperature Rise = T (out) - T (in)
5. Energy equation - - BTU/hr = SCFM x Temperature Rise x 1.08 / 0.92
Where: 1.08 is a sensible heat equation constant
1.08 = 0.2397
(BTU )x 60 (min) x 0.075 (lb )
____ ___ ___
lb H Ft3
___________________________________
Profile Setup Example
Continued
Profile Velocity 0750
945 PΔ =
.
Profile Velocity 0750
945=
.
0.8=3086(SFPM)
Profile Velocity 0750
945=
.
0.4=2182(SFPM)

8Midco International Inc. 8471 34
NOTE: If burner is over 4′, natural gas, or 5′, propane gas, a back inlet is required as shown
below. Gas Inlet Capacities
Maximum Feet of Burner
Inlet Size Natural Propane
1.5 ″NPT End Inlet 4′5′
2″NPT Back Inlet 6.5′8′
Centrally Located
___________________________________
The performance of the HMA-2 & 2A burner depends on the unit in which the burner is located. The
burner can perform differently in different units and can obtain different end results. Maintaining a
relative laminar flow around the burner and providing a sufficient space between the burner and
the blower is a key factor in obtaining best burner performance. The unit should be free of any
obstructions that can create turbulent effect on the air.
Note: Any reinforcements around the profile plates should be down stream of the profile plate.
Static pressure probes are needed to sense the differential air pressure across the profile plates.
The static pressure probes should be installed 12″upstream from the burner and 12″downstream
from the burner centrally located in the duct. See Figure 1a and 1b for typical location.
Burner Assembly
Burner Placement
in the Profile
Installation
Air Flow
Adjustable
Profile Plate
Fixed
Profile Plate
Profile
Opening
should be
Centered to
the Burner
Burner should
be Centered
to the Blower
12" 12"
Static
Pressure
Probe
Static
Pressure
Probe
1" to 4", typical 2"
Air Flow
Burner should
be Centered
to the Blower
4"
4"
Figure 1b - Burner Placement in the Profile
Figure 1a - Burner Placement in the Profile
Table 4 - Gas Inlet Capacities

Midco International Inc. 9
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The burner performance is highly dependent on its application and installation in the heater.
Factors such as airflow around the burner, positioning in the profile, as well as, the profile sizing
have influence on the final emissions levels . Midco does not guarantee combustion results prior to
performing actual combustion tests.
The burner should be located in the center of the profile. The profile clearance from ends of the
burner should be kept at approximately 1 to 4-inches. Typically setting the profile 2″from the end
plates is recommended. Any reinforcements used on the edge of the profile opening should be
on the downstream side of the profile. The burner can be mounted either vertically or horizontally.
Since the airflow varies from unit to unit best results should be determined by actual testing.
___________________________________
The HMA-2 & 2A Burners are designed to operate in an air heater and in an air stream taken directly
from outdoors for most applications. To avoid stratification of the heated air, the burners should be
located on the intake side center to the blower. Such positioning will take advantage of the blower
mixing effect and ensure minimum temperature stratification. It will also allow for a relatively uniform
airflow across the burner resulting in a clean combustion.
The total pressure of the blower must include allowance for the resistance of the heater and
pressure drop across the burner, together with pressure losses at the inlet screen, inlet louvers,
filters, plus the external pressure rating of the heater, if any. Contact equipment manufacturer for
proper information.
___________________________________
The HMA-2 & 2A Burner will operate satisfactorily when located downstream of the blower. A
mixing plenum may be required at the heater discharge opening to insure minimum temperature
stratification. Blower and motor selection must be made on the basis of corrections for the coldest
anticipated inlet temperature. In the push-thru system the heater outlet CFM will vary due to the
expansion of air.
Installation
Figure 2 - Pull-Thru System
Installation in a Heater
Screen
and
Filter
Air Inlet
Weatherhood
HMA-2 &
HMA 2A
Burner
Adjustable
Profile Plate
Outlet
Blower Inlet
Center Burner
to the Blower
x
2x
Pull Thru System
Push-Thru Systems
Push-Thru System
Air Inlet Outlet
Blower Inlet
Center Burner
to the Opening
Figure 3 - Push Thru System
Burner Placement
in the Profile
Continued

10 Midco International Inc. 8471 34
___________________________________
Installation
Figure 5a - Gas Train Assemblies
Typical Gas Train Assembly
Figure 4 - Installation in a Duct
Elbow Duct Limits
Minimum Straight
Run 1-1/2 x "A"
Duct Height "A"
3 Ft. Minimum Minimum Straight
Run 2 x "B"
3 Ft. Minimum
Duct Width "B"
Air Flow
Air Flow
Profile Plate Profile Plate
Push-Thru Systems
Continued
Typical
Gas Train
Assembly
400,000 BTU/Hr
and Under
Flame Rod
Pilot
Spark Rod
Burner
Pilot Tube
Union
Modulating Valve
Manual Pilot Valve
Combination Gas Valve with
Main & Pilot Regulator
Main Manual
Gas Valve *
A heater having an input over
400,000 BTU/Hr shall have
provisions for measuring gas
pressure between the valves,
except for heater incorporating
a single safety shut-off valve
with valve seal over travel
interlock. (ANSI Z83.4)
* A manifold pressure tap
needs to be provided
at the burner to check
manifold pressure
Flame Rod
Pilot
Spark Rod
Burner
Pilot Tube
Union
Manual
Firing Valve
Modulating
Valve
Pilot
Regulator
Pilot
Valve
Manual Pilot
Valve
Main Manual
Gas Valve
Main
Regulator
Main
Operating
Valves
Safety Shut-off
Valve
Pilot Gas Pressure Tap
*
Typical Gas
Train Assembly
400,000 BTU/Hr
and Above

Midco International Inc. 11
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Installation
___________________________________
Burner operation depends on the unit control setup in which the HMA-2 & 2A burner is used. A
typical setup should consist of a Flame Safety Control with appropriate air flow proving system and
a Modulating Gas Control System.
1. Verify the pressure across the burner. The pressure across the burner can be measured by
placing two static pressure probes, one downstream and one upstream of the profile opening
and measure the differential pressure. The pressure should be within burner operating
specifications and within the expected calculated pressure. See Chart 2
2. With the burner offcheck the Flame Safety Air Proving System
a. Check the operation of the air proving system for low and high airflow setting. Refer to
the Specifications of the Flame Safety Control for setup instructions and air switch
operational characteristics.
Burner Setup
Typical Gas Train Assembly
Continued
Figure 5b - Direct Spark Gas Train Assemblies
Main Manual
Gas Valve
Combination Gas
Valve with Main
& Pilot Regulator
Modulating Valve
Manual Firing Valve
Union
*
Burner
Pilot
Flame Rod
Spark Rod
Direct Spark Ignition Typical
Gas Train Assembly 400,000 BTU/Hr
and Under
Main Manual Gas Valve
Main
Regulator
Main Operating
Valves
Safety Shut-off
Valve
Manual Pilot Valve
Pilot Regulator
Pilot Gas Pressure Tap
Modulating Valve
Main Gas
Pressure Tap
Manual Firing Valve
Union
*
Burner
Pilot
Flame Rod
Spark Rod
Direct Spark Ignition
Typical
Gas Train Assembly

12 Midco International Inc. 8471 34
3. For intermittent, or interrupted ignition systems. See Figure 5a for typical piping.
a. Pipe the pilot gas supply line up stream of the main gas valve.
b. With the unit running adjust the pilot pressure regulator to 3.5 inch W.C. for natural gas
or 2.0 inch W.C. for propane gas. Using a natural gas pilot or 5″to 7″, using a propane
pilot with orifice # 4957-07 (#58 Drill .042)
4. For direct spark ignition system when using a pilot for ignition. See Figure 5b.
a. Pipe the pilot gas supplied line to the main gas line downstream of the main gas valve.
5. Pilot ignition
a. Make sure the main gas valve to the burner is closed for intermittent or interrupted
ignition.
b. Observe the pilot flame, the flame should be blue and should extend approximately to
half of the burner end plate.
c. Check the flame signal.
d. Flame signal should be between 2-5 UA or 2-5 VDC
6. Depending on the pilot configuration make following adjustments, if required.
a. For Spark rod and flame rod configurations
Make sure the flame rod is pointing towards burner manifold.
Make sure the flame rod is not touching baffles or burner manifold.
Make sure the spark rod is positioned above the pilot gas tube and that it will spark to
the end of the gas tube. See Pilot Detail Drawings for this setting on page 15.
b. Spark rod and UV
Make sure the spark rod is positioned above the pilot gas tube and that it will spark to
the end of the gas tube.
7. Main burner ignition
Close the manual gas valve.
a. Set the Modulating Gas Control System to low fire position.
· Slowly open the manual gas valve.
· The flame should be evenly extending in the burner.
· The flame should be located in the casting of the burner.
· Check the flame signal.
Close the manual gas valve.
b. Set the Modulating Gas Control System to high fire position.
· Slowly open the manual gas valve.
· Observe the flame at high fire; the flame should be blue approximately 10 to
12″long. If the flame is long, lazy and orange the air to fuel ratio is not correctly
adjusted . The pressure across the burner should be increased, refer to Chart 2.
· Check the flame signal.
· Check the manifold pressure to the corresponding firing rate. If the manifold
pressure does not correspond to the pressures shown in Chart 3. Re-adjust if
necessary.
For a high fire start system the first gas port next to the pilot might require to be blocked using
furnace cement to prevent potential pilot blow outs and flame failures. See Figure 7 - Pilot
Configuration.
Slight redness and warpage of the baffle plates may occur at the high and intermediate fire inputs.
This will not harm the burner. Once an initial discoloration and warp has taken (“set”) no further
permanent change will take place.
If the end plates redness occurs during high and intermediate fire inputs, the distance between the
end plates and the profile opening might not be sufficient for the air to cool the end plates. Profile
readjustments might be necessary.
___________________________________
Installation
Burner Setup Continued

Midco International Inc. 13
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Burner Trouble Shooting
The Midco Burner is only a component of the complete system. For trouble shooting of the
equipment contact the OEM (Original Equipment Manufacturer) or the component manufacturer.
If the pilot fails to light: install a manometer on the pilot pressure tap. Check for 3.5″W.C. for
natural gas or 2″W.C. for propane, using a natural gas pilot or 5″to 7″using a propane pilot with
orifice # 4957-07 (#58 Drill .042). If no gas check for voltage to pilot solenoid valve. If no voltage
check operating controls or primary flame safeguard. If voltage to pilot solenoid valve is present
and if there is 3.5″W.C. gas pressure at pilot pressure tap then check for spark or flame rod
settings. See Figure 7. If there is no voltage to pilot solenoid valve, refer to Flame Safety control
specifications or contact the original equipment manufacturer.
If Main Burner fails: If no main flame check manifold pressure. If no manifold pressure check for
voltage to the gas solenoid valve and check if main manual firing valve is open. If no voltage to gas
valve refer to Flame Safety control specifications or contact the original equipment manufacturer.
If the pilot fails as main gas valves open, the first adjacent gas port hole (next to the pilot) might
need to be plugged with furnace cement. For high fire start units see Figure 7 - Pilot Configuration.
___________________________________
Annual maintenance of HMA 2 & HMA 2A burner is recommended to ensure trouble free operation.
Direct Gas-Fired Heater Burner Maintenance
1. Clean the burner plates
2. Clear the burner gas and air ports
3. Change the spark rod igniter
4. Insure the flame sensor is in good condition
Use a stiffwire brush to clean the burner plates. Scrub both sides of the stainless steel burner plates
to remove any soot or other crud, which may be on the burner. All of the burner plate holes must
be clear so air can pass through them unrestricted. The holes in the burner plate allow air to mix
with the gas in increasing amounts, as the flame gets longer. Scrub the rust, soot and other foreign
material from the burner orifice area. After the burner plates are cleaned inspect them for cracking.
Cracks occurring between one or two holes are normal and should be of no concern. If the cracking
is more extensive, the affected plates should be replaced. Clean the burner gas and air ports using a
drill or piece of wire of the appropriate size. See the Table 5 for drill size. After the orifices are drilled
to the correct size and using compressed air or a vacuum, remove any debris from the manifold.
Debris left in the manifold will prematurely clog the orifices in the future.
Gas Port Air Port
Burner Section and Gas Type Drill Size Decimal Drill Size Decimal
Wire Gauge Wire Gauge
HMA 2 Natural / Propane 1/8″.125 43 .089
HMA 2A Natural / Propane 1/8″.125 42 .093
Table 5 - Drill Sizes for HMA 2 / 2A
After the burner plates and orifices are cleaned inspect the spark rod. The tip should be clean and
free of dirt and carbon. The porcelain must be intact. If it is cracked, replace it. Pull the flame rod or
ultraviolet scanner as well. If the flame sensor is a scanner, clean the lens with a clean damp soft
rag. The flame rod’s metal rod should be clean and free of dirt and carbon. Like the spark rod igniter,
the porcelain on the flame rod must be intact as well. Replace it if it is cracked.
___________________________________
Burner Maintenance

14 Midco International Inc. 8471 34
Figure 6 - Burner Sections - Assembly
4.11"
8.22"
6" Straight
10.47"
8.63"
6.00"
12" Straight
10.47"
8.63"
12.00"
2" Straight
10.47"
8.63"
2.0"
6" Straight with
2" NPT Back Inlet
8.63"
11.38"
6.00"
2" NPT
Inlet
12" Straight with
2" NPT Back Inlet
11.38"
8.63"
6.00"
12.00"
2" NPT
Inlet
Elbow
Section
8.63"
10.47"
6.00"
10.11"
Tee Section
10.47"
8.63"
6.00"
12.00"
12" Straight6" Straight
12" Straight with
2" NPT Back Inlet
6" Straight with
2" NPT Back Inlet Ell
Tee
Cast Iron
HMA 2 -1050700
HMA 2A - 1050710
Aluminum
HMA 2 - 1050800
HMA 2A - 1050810
Cast Iron
HMA 2 -1010700
HMA 2A - 1010710
Aluminum
HMA 2 - 1010800
HMA 2A - 1010810
Cast Iron
HMA 2 -1080700
HMA 2A - 1080710
Aluminum
HMA 2 - 1080800
HMA 2A - 1080810
Cast Iron
HMA 2 -1230700
HMA 2A - 1230710
Aluminum
HMA 2 - 1230800
HMA 2A - 1230810
Cast Iron
HMA 2 -1060700
HMA 2A - 1060710
Aluminum
HMA 2 - 1060800
HMA 2A - 1060810
Cast Iron
HMA 2 -1070700
HMA 2A - 1070710
Aluminum
HMA 2 - 1070800
HMA 2A - 1070810
2" Straight
Aluminum
HMA 2A - 1050810
Burner Configuration
Caution:
Under no
circumstances are
the HMA-2 baffles
and the HMA-2A
baffles or castings
to be mixed. For
further details see
service bulletin
# 8449-83.
Caution:
Under no
circumstances
should grade
hardware or
Aluminum rivets
be used.
!
!

Midco International Inc. 15
8471 34
Parts - Pilot Configuration & Mounting
1190800
Spark Rod &
Flame Rod
Direct Spark
1220800
Remote
Flame Rod
1210800
Pilot with Spark
Rod Only
1200300
Spark Rod
and UV
1240800
Remote UV
Pilot Detail - Spark Gap Measurement
Brute Pilot - UV Scanner Mount
1200350
1/8"
Brute Pilot - w/ Spark Rod
1190850
Brute Pilot
1190850
1190850
Spark Rod &
Flame Rod
Brute Pilot
1200350
Spark Rod
and UV
Brute Pilot
3.72"
2.96"
5.57"
3.72"
5.57" 0.65"
Location of First Burner Port Plug - See Installation,
Burner Setup Section or Trouble Shooting Section
(Used on high fire start systems ONLY)
3.72"
2.96"
5.57"
Figure 7 - Pilot Configuration

16 Midco International Inc. 8471 34
8
6
11
10
24
4
3
11
14
2
13
1
15
12 8
6
7
11
10
9
16
2” Straight
6” Straight
12” Straight
Ell Section
Tee Section
5
18
3
1
111
21
23
19
20
4
25
1
14
6
22
17
6
Figure 8 - Typical Burner Assembly Parts - Isometric View
Parts - Isometric View - HMA 2 & HMA 2A

Midco International Inc. 17
8471 34
Table 5 - Burner Assembly Parts
Parts List for Isometric View
Item Number in Isometric View * #12 #15 #16 #23 #22 #6 #28
2″6″6″12″12″Elbow Tee
Burner Castings Straight Straight Back Inlet Straight Back Inlet Section Section
Part #s for Cast Iron HMA 2 N/A 1359-25 1398-25 1364-25 1361-25 1362-25 1365-25
Part #s for Cast Iron HMA 2A N/A 1359-30 1398-30 1364-30 1361-30 1362-30 1365-30
Part #s for Aluminum HMA 2 N/A 1359-75 1398-75 1364-75 1361-75 1362-75 1365-75
Part #s for Aluminum HMA 2A 1370-18 1359-80 1398-80 1364-80 1361-80 1362-80 1365 -80
Item
No. Part Description Part No Quantity Quantity Quantity Quantity Quantity Quantity Quantity
1 S62 Steel Rivet Body Hardware 12 12 12 22 22 22 26
2 HMA-2A 2″Baffle 1355-55 2
3 HMA Pilot End Plate 1354-60 Select the correct required end plates
4 Blank End Flange 1372-52 Select the correct required end plates
5 Mounting Bracket 1130100 2 2 2 2 2 2 3
6 HMA-2A 6″Baffle 1395-23 2 2 4 4 2 2
7 HMA-2A Outside
Corner Baffle 1395-35 1
8 HMA-2/2A Tee Baffle 1395-11 1 2
9 Elbow Casting Section * See above listing for proper selection
10 Inside Baffle Clamp 1356-10 2 4
11 10-24x9/16 Phillips Rd
Hd S.S. Mach Screw Hardware 2 4 4 8 8 8 12
12 Baffle Clamp - 2″1356-20 2
13 2″Casting (2A only) * See above listing for proper selection
14 HMA Blank End Plate 1354-50 Select the correct required end plates
15 1/2″NPT Inlet Flange 1372-05 Select the correct required end plates
16 6″Straight Casting * See above listing for proper selection
17 6″Back Inlet Casting * See above listing for proper selection
18 Pilot See pilot listing on Page 15 - Pilot Configuration (For selection)
19 5/16-18 x 2″Hex
Head Cap Screw Hardware 3 3 3 3 3 3 6
20 Inlet Flange (Tapered) 1352-52 (Select the correct required end plates
21 Baffle Clamp 1356-00 2 2 4 4 2 2
22 12″Back Inlet Casting * See above listing for proper selection
23 12″Straight Casting * See above listing for proper selection
24 Tee Section Casting * See above listing for proper selection
25 5/16-18x 1-3/4″Hex
Head Cap Screw Hardware 3 3 3 3 3 3 3
Not Shown
5/16 Lock Washer Hardware 6 6 6 6 6 6 9
5/16-18 Hex Nut Hardware 6 6 6 6 6 6 9
Burner Configurations: see page 14 for complete burner sections

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 34
ISO
9001
C
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P
A
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1219
Figure 9 shows the assembly of a typical HMA 2 and HMA 2A direct fired burner assembly for both
“in field” and factory assembly line.
A) 1-1/2″Inlet Flange With Pilot Mount or Blank Plate Hardware Required:
Furnace Cement (See Notes # 1)
8 Stainless Steel Pcs of 10-24 X 3/8″Slotted Round Head Screw,
10-24 Hex Nut, 10-24 Lock Washer (Rivet Gun Required)
3 Pcs 5/16″X 2″Hex Cap Screws
3 Pcs 5/16″Lock Washers
3 Pcs 5/16″-18 Nuts
B) Blank Flange With Blank Plate or Pilot Mount Plate Hardware Required:
Furnace Cement (See Notes # 1)
8 Stainless Steel Pcs of 10-24 X 3/8″Slotted Round Head Screw,
10-24 Hex Nut, 10-24 Lock Washer (Rivet Gun Required)
3 Pcs 5/16″X 1-3/4″Hex Cap Screws
3 Pcs 5/16″Lock Washers
3 Pcs 5/16″-18 Nuts
Notes:
1) Furnace cement is to be applied between the casting and either blank plate, pilot plate and
end flanges only, not between baffles and end plates.
2) The hardware listed on instructions A and B applies to each end of any size burner with such
configuration.
3) For definition and views of burner section, plates, flanges, or hardware refer to page 16 and
17 of the Installation and Service Instructions manual.
4) Burner drawing symbols represent a view of the burner from side opposite the flame exit.
5) In the absent of a rivet gun, use the hardware specified on these instructions, stainless steel
hardware is highly recommended.
UNDER NO CIRCUMSTANCES SHOULD STANDARD GRADE
OR ALUMINUM RIVETS BE USED.
6) Hardware used between burner sections is the same as the hardware used on Instructions B.
7) Pilot hardware Is Included with the pilot assembly.
8) If Installing mounting brackets, they must be Installed on the exterior side of the Inlet or blank
flange.
UNDER NO CIRCUMSTANCES SHOULD THEY BE INSTALLED
BETWEEN THE FLANGE AND THE BURNER CASTING.
___________________________________
Burner Assembly Instructions
AB
Burner Assembly
Instructions
Figure 9 - Typical HMA 2 & HMA 2A 6″Direct Fire Burner Assembly