Midco HMA-2A Service Manual

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Page 1

Installation and Service Instructions

MADE in the USA

HMA 2 & HMA 2A

Direct-Fired Gas Burners

The Blue Flame Series

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 modiﬁ cation or improvement of the old, but a completely new approach to direct-ﬁ red combustion. The two-stage combustion improves control of the ﬂ ame process, meets or exceeds the new ANSI Standards while outperforming the competition. By incorporating two separate ﬂ ames within the burner combustion zone, the ﬂ ame 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 proﬁ le opening.

Features and Beneﬁ ts

Reduced NO2 and 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 NO 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 NO

emissions are not of a concern. Process heaters can ﬁ re

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 ﬂ ame stability and emission control, allowing for a shorter ﬂ ame and easier proﬁ le conﬁ guration.

Reduced Inventory Costs - HMA 2A: Single burner casting can be ﬁ red with natural, propane or butane gas 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.)

emissions which is the limiting factor in

, reducing

Midco® International Inc. 4140 West Victoria Street Chicago, Illinois 60646 toll free 866.705.0514 tel 773.604.8700 fax 773.604.4070 web www.midcointernational.com e-mail sales@midcointernational.com

Emission performance is application speciﬁ c and may vary.

Consult Midco for applications using butane fuels.

Quality Designed for Proven Performance

1113

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Printed in USA

Page 2

Speciﬁ cations

*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 ﬂ ame 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.

Cast Iron (CI) Aluminum (AL)

*** Burner Conﬁ gurations 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 Conﬁ gurations 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

Spark Rod (Direct Spark) 1342-06

*** See Page 14, Figure 6 for burner conﬁ guration reference.

**** See Page 15, Figure 7 for pilot conﬁ guration reference

(Direct Spark, Std + Brute)1360-03

Table 1 - Burner and Pilot Conﬁ gurations

Midco International Inc. reserves the right to change the construction or conﬁ guration of its products at any time. All information is based on laboratory testing. Different unit size and/or conﬁ gurations may affect data.

Midco International Inc.

8471 34

Page 3

HMA 2 & HMA 2A Burner Performance

Burner Performance

5.0

4.0

CO Emission

3.0

2.0

CO (PPM)

1.0

0.0 0

40 60 80 100 120

Temperature Rise*

750,000 Btu/hr/ft at 1.1" W.C. pressure drop across the burner

5.0

4.0

CO Emission

3.0

2.0

CO (PPM)

1.0

0.0

0 20406080100

Temperature Rise*

550,000 Btu/hr/ft at 0.6" W.C. pressure drop across the burner

5.0

4.0

120

0.5

NO Emission

0 20406080100120

0.4

0.3

0.2

0.1

0.0

Temperature Rise*

750,000 Btu/hr/ft at 1.1" W.C. pressure drop across the burner

0.5

NO Emission

0 20406080100120

0.4

0.3

0.2

0.1

0.0

Temperature Rise*

550,000 Btu/hr/ft at 0.6" W.C. pressure drop across the burner

0.5

NO Emission

0.4

NO (PPM)

3.0

2.0

CO (PPM)

1.0

0.0 0 20406080100

CO Emission

120

Temperature Rise*

350,000 Btu/hr/ft at 0.35" W.C. pressure drop across the burner

100

NO (PPM at 3% O )

0.0 0

NO Emissions Profile

100000 200000 300000 400000 500000 600000

Heat Input (Btu/hr/ft)

0.3

0.2

0.1

40 60 80 100 120

0.0

Temperature Rise*

350,000 Btu/hr/ft at 0.35" W.C. pressure drop across the burner

.45 Delta P

.64 Delta P

.85 Delta P

* For higher temperature rise contact Midco Engineering Department.

NOTE: Emission performance is application specific and will vary

NO (PPM)

8471 34

Chart 1 - CO and NO2 Emissions Data

Midco International Inc.

Page 4

HMA 2 & HMA 2A Burner Performance

Burner Performance Continued

800,000

700,000

600,000

BTU/hr/ft

500,000

400,000

300,000

9.0

8.0

7.0

6.0

5.0

4.0

(Manifold)

3.0

Natural Gas

Propane Gas

0.20 0.40 0.60 0.80 1.00 1.20

Pressure Drop across the Burner ("W.C.)

Chart 2- BTU’s verses Pressure Drop

Natural Gas

2.0

Fuel Gas Pressure ("W.C.)

1.0

0.0 100,000 200,000 300,000 400,000 500,000 600,000 700,000

Propane Gas

BTU/hr/ft

Chart 3- BTU’s verses Gas Pressure ( ″W.C.)

4,500

4,000

3,500

3,000

2,500

2,000

Profile Velocity (SFPM)

1,500

1,000

0.20 0.40 0.60 0.80 1.00 1.20

Pressure Across the Burner ("W.C.)

Chart 4 - Pressure Across the Burner verses Proﬁ le Velocity

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Midco International Inc.

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Page 5

Installation

- Velocity and pressure drop ﬁ gures 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 ﬁ gures 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 ﬂ ow at burner Approximate length of ﬂ ame based on 70° (std) Burner Capacity (per foot) projecting beyond end of blower rating Natural & Propane Gas burner and proﬁ le 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 3200 .7″ 550,000 19,000 29:1 13″ 16″ 20″ 2850 (ideal) 2500 .45″ 550,000 17,000 32:1 17″ 20″ 24″

Reduce capacity 4% per each 1000 ft altitude over 2000 ft.

.55″ 550,000 18,000 30:1 15″ 19″ 22″

Table 2 - Design Data for Pull-Thru System

* Flame lengths are given to the end of the main mass of ﬂ ame, excluding any isolated wisps or ﬂ ashes, and for normal operations ie. with cold inlet air (design minimum)

Air Flow Variations Due to Heating in a

Pull-Thru System

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

3200 fpm .7″ W.C.

100° 2600 fpm .46″ W.C.

2850 fpm .55″ W.C.

100° 2300 fpm .36″ W.C.

2500 fpm .45″ W.C.

100° 2000 fpm .29″ W.C.

75° 2750 fpm .52″ W.C.

75° 2450 fpm .41″ W.C.

75° 2150 fpm .33″ W.C.

Table 3 - Air Flow Variations for Pull-Thru System

EXAMPLE: A heater rated for 100° rise, 70° outlet temperature at a design velocity of 2850 fpm and a design pressure drop of .55″ W.C., will in actual operation pass 2300 fpm over the burner with a .36″ W.C. drop when air enters at -30°.

HMA 2 & HMA 2A Flame Length

750,000 Btu/ft

650,000 Btu/ft

550,000 Btu/ft

Flame Length ( inches )

1.20.2 0.4 0.6 0.8 10

Pressure Drop ( " W.C.)

Chart 5 - HMA 2 & 2A Flame Length

HMA 2 & HMA 2A ﬂ ame length as a function of pressure drop and ﬁ ring rate applies to push and pull through systems using 100% fresh standard air.

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Midco International Inc.

Page 6

Installation

Proﬁ le Setup

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 Proﬁ le 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 Proﬁ le Area = Rated Fan (SCFM) ÷ Proﬁ le Velocity (SFPM) The Proﬁ le Velocity can be determined from the following:

Profile Velocity

∆P is the pressure drop across the burner

Proﬁ le Area = Net Proﬁ le Area + Total Burner Area ___________________________________

945

PΔ

0750

Proﬁ le Setup Example

Sizing the burner and the corresponding proﬁ le 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 ﬁ re the burner at a rate of 675,000 BTU/hr per ft, or we can ﬁ re 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 ﬁ ring rates.

3. Required Proﬁ le 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.

Total Burner Area = 1.0 (ft) x 0.65 = 0.650 ft Or Total Burner Area = 1.5 (ft) x 0.65 = 0.975 ft

Midco International Inc.

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Page 7

Installation

Net Proﬁ le Area = Rated Fan (SCFM) ÷ Proﬁ le Velocity (SFPM)

The Proﬁ le Velocity should be determined based on the burner ﬁ ring rates. If we choose to ﬁ re the burner at 675,000 BTU/hr/ft then the proﬁ le opening should be sized for a pressure drop of 0.8 ″ W.C. across the burner. If the ﬁ ring rate is 450,000 BTU/hr/ft then the proﬁ le opening should be sized for a pressure drop of 0.4 ″ W.C. across the burner. The corresponding proﬁ le velocity across the burner should be determined from Chart 4 or use the following equation.

0750

PΔ

0750

3086(SFPM)

2182(SFPM)

Profile Velocity

For the 675,000 BTU/hr/ft

Profile Velocity

Net Proﬁ le Area = 5000 (SCFM) ÷ 3086 (SFPM)=1.62ft

For the 450,000 BTU/hr/ft

Profile Velocity

Net Proﬁ le Area = 5000 (SCFM) ÷ 2182 (SFPM)=2.29ft

To calculate the proﬁ le area needed for both cases:

Proﬁ le Area = Net Proﬁ le Area + Total Burner Area

For the 675,000 BTU/hr/ft Proﬁ le Area = 1.62 + 0.650 = 2.27 ft

945

0.8

0.4

Proﬁ le Setup Example

Continued

For the 450,000 BTU/hr/ft Proﬁ le Area = 2.29 + 0.975 = 3.265 ft

To calculate the length of the proﬁ le opening add burner length to the desired clearance:

For the 675,000 BTU/hr/ft case 12 inch + 4 inch (2 inch on each side) = 16 inch (1.3ft) For the 450,000 BTU/hr/ft case 18 inch + 4 inch (2 inch on each side) = 22 inch (1.83ft)

To calculate the height of the proﬁ le opening divide the proﬁ le area by the proﬁ le length:

For the 675,000 BTU/hr/ft case

2.27 ft For the 450,000 BTU/hr/ft case

3.265 ft

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

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

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

____ ___ ___

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8471 34

÷ 1.3 ft = 1.75 ft (21 inch)

÷ 1.83 ft = 1.78ft (21.5 inch)

BTU

(

x 60 ( min) x 0.075 ( lb

)

lb H Ft

+ 460

(out)

- T

(out)

(in)

)

Midco International Inc.

Page 8

Installation

Burner Assembly

Burner Placement in the Proﬁ le

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

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Table 4 - Gas Inlet Capacities

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 ﬂ ow around the burner and providing a sufﬁ cient 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 proﬁ le plates should be down stream of the proﬁ le plate.

Static pressure probes are needed to sense the differential air pressure across the proﬁ le 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.

Adjustable Profile Plate

Static Pressure Probe

Fixed Profile Plate

Profile Opening should be Centered to the Burner

Static Pressure Probe

Air Flow

Burner should be Centered to the Blower

12"

Figure 1a - Burner Placement in the Proﬁ le

1" to 4", typical 2"

Burner should be Centered to the Blower

12"

Figure 1b - Burner Placement in the Proﬁ le

Midco International Inc.

8471 34

Page 9

The burner performance is highly dependent on its application and installation in the heater. Factors such as airﬂ ow around the burner, positioning in the proﬁ le , as well as, the proﬁ le sizing have inﬂ uence on the ﬁ nal emissions levels . Midco does not guarantee combustion results prior to performing actual combustion tests.

The burner should be located in the center of the proﬁ le. The proﬁ le clearance from ends of the burner should be kept at approximately 1 to 4-inches. Typically setting the proﬁ le 2″ from the end plates is recommended. Any reinforcements used on the edge of the proﬁ le opening should be on the downstream side of the proﬁ le. The burner can be mounted either vertically or horizontally. Since the airﬂ ow varies from unit to unit best results should be determined by actual testing. ___________________________________

Installation

Burner Placement

in the Proﬁ le

Continued

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 stratiﬁ cation 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 stratiﬁ cation. It will also allow for a relatively uniform airﬂ ow across the burner resulting in a clean combustion.

Weatherhood

Air Inlet

Screen and Filter

Adjustable Profile Plate

HMA-2 & HMA 2A Burner

Installation in a Heater

Blower Inlet

Outlet

Center Burner to the Blower

Figure 2 - Pull-Thru System

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, ﬁ lters, plus the external pressure rating of the heater, if any. Contact equipment manufacturer for proper information.

___________________________________

Push-Thru System

Center Burner to the Opening

Pull Thru System

Push-Thru Systems

Air Inlet

Blower Inlet

Outlet

Figure 3 - Push Thru System

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 stratiﬁ cation. 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.

8471 34

Midco International Inc.

Page 10

Installation

Push-Thru Systems Continued

Profile Plate

Duct Height "A"

Profile Plate

Duct Width "B"

Typical Gas Train Assembly

Air Flow

Minimum Straight Run 2 x "B"

Air Flow

Minimum Straight Run 1-1/2 x "A"

3 Ft. Minimum

Elbow Duct Limits

Figure 4 - Installation in a Duct

___________________________________

Typical Gas Train Assembly 400,000 BTU/Hr and Under

Main Manual Gas Valve

Typical Gas Train Assembly 400,000 BTU/Hr and Above

Main Regulator

Main Manual Gas Valve

Manual Pilot Valve

Flame Rod

Spark Rod

Combination Gas Valve with Main & Pilot Regulator

Main Operating Valves

Pilot Val ve

Pilot

Modulating Valve

Manual Pilot Valve

Safety Shut-off Valve

Pilot Regulator

Pilot Gas Pressure Tap

Union

Pilot Tube

Burner

Spark Rod

Pilot Tube

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)

Pilot

Flame Rod

Modulating Valve

* A manifold pressure tap needs to be provided at the burner to check manifold pressure

3 Ft. Minimum

Union

Manual Firing Valve

Burner

Figure 5a - Gas Train Assemblies

Midco International Inc.

8471 34

Page 11

Direct Spark Ignition Typical Gas Train Assembly 400,000 BTU/Hr and Under

Installation

Typical Gas Train Assembly

Continued

Pilot

Flame Rod

Spark Rod

Burner

Main Regulator

Main Manual Gas Valve

Main Operating Valves

Combination Gas Valve with Main & Pilot Regulator

Main Manual Gas Valve

Direct Spark Ignition Typical Gas Train Assembly

Safety Shut-off Valve

Pilot Regulator

Manual Pilot Valve

Main Gas Pressure Ta p

Modulating Valve

Flame Rod

Spark Rod

Modulating Valve

Pilot Gas Pressure Tap

Union

Manual Firing Valve

Pilot

Union

Manual Firing Valve

Pilot Tube

* A manifold pressure tap needs to be provided at the burner to check manifold pressure

Burner

Figure 5b - Direct Spark Gas Train Assemblies

___________________________________

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 ﬂ ow 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 proﬁ le opening and measure the differential pressure. The pressure should be within burner operating speciﬁ cations and within the expected calculated pressure. See Chart 2

2. With the burner off check the Flame Safety Air Proving System a. Check the operation of the air proving system for low and high airﬂ ow setting. Refer to the Speciﬁ cations of the Flame Safety Control for setup instructions and air switch operational characteristics.

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Midco International Inc.

Burner Setup

Page 12

Installation

Burner Setup Continued

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 oriﬁ ce # 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 ﬂ ame, the ﬂ ame should be blue and should extend approximately to half of the burner end plate. c. Check the ﬂ ame signal. d. Flame signal should be between 2-5 UA or 2-5 VDC

6. Depending on the pilot conﬁ guration make following adjustments, if required. a. For Spark rod and ﬂ ame rod conﬁ gurations Make sure the ﬂ ame rod is pointing towards burner manifold. Make sure the ﬂ ame rod is not touching bafﬂ es 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 ﬁ re position.

· Slowly open the manual gas valve.

· The ﬂ ame should be evenly extending in the burner.

· The ﬂ ame should be located in the casting of the burner.

· Check the ﬂ ame signal. Close the manual gas valve. b. Set the Modulating Gas Control System to high ﬁ re position.

· Slowly open the manual gas valve.

· Observe the ﬂ ame at high ﬁ re; the ﬂ ame should be blue approximately 10 to 12 inches long. If the ﬂ ame 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 ﬂ ame signal.

· Check the manifold pressure to the corresponding ﬁ ring rate. If the manifold pressure does not correspond to the pressures shown in Chart 3. Re-adjust if necessary.

For a high ﬁ re start system the ﬁ rst gas port next to the pilot might require to be blocked using furnace cement to prevent potential pilot blow outs and ﬂ ame failures. See Figure 7 - Pilot Conﬁ guration.

Slight redness and warpage of the bafﬂ e plates may occur at the high and intermediate ﬁ re 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 ﬁ re inputs, the distance between the end plates and the proﬁ le opening might not be sufﬁ cient for the air to cool the end plates. Proﬁ le readjustments might be necessary.

___________________________________

Midco International Inc.

8471 34

Page 13

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 oriﬁ ce # 4957-07 (#58 Drill .042). If no gas check for voltage to pilot solenoid valve. If no voltage check operating controls or primary ﬂ ame 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 ﬂ ame rod settings. See Figure 7. If there is no voltage to pilot solenoid valve, refer to Flame Safety control speciﬁ cations or contact the original equipment manufacturer.

If Main Burner fails: If no main ﬂ ame check manifold pressure. If no manifold pressure check for voltage to the gas solenoid valve and check if main manual ﬁ ring valve is open. If no voltage to gas valve refer to Flame Safety control speciﬁ cations or contact the original equipment manufacturer.

If the pilot fails as main gas valves open, the ﬁ rst adjacent gas port hole (next to the pilot) might need to be plugged with furnace cement. For high ﬁ re start units see Figure 7 - Pilot Conﬁ guration. ___________________________________

Burner Maintenance

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 ﬂ ame sensor is in good condition

Use a stiff wire 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 ﬂ ame gets longer. Scrub the rust, soot and other foreign material from the burner oriﬁ ce 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 oriﬁ ces 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 oriﬁ ces 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 oriﬁ ces 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 ﬂ ame rod or ultraviolet scanner as well. If the ﬂ ame sensor is a scanner, clean the lens with a clean damp soft rag. The ﬂ ame rod’s metal rod should be clean and free of dirt and carbon. Like the spark rod igniter, the porcelain on the ﬂ ame rod must be intact as well. Replace it if it is cracked. ___________________________________

8471 34

Midco International Inc.

Page 14

Burner Conﬁ guration

2" Straight

Aluminum HMA 2A - 1050810

2.0"

8.63"

10.47"

Cast Iron HMA 2 -1050700 HMA 2A - 1050710

Aluminum HMA 2 - 1050800 HMA 2A - 1050810

6" Straight with

2" NPT Back Inlet Cast Iron

HMA 2 -1230700 HMA 2A - 1230710

Aluminum HMA 2 - 1230800 HMA 2A - 1230810

6.00"

8.63"

10.47"

12" Straight6" Straight Cast Iron HMA 2 -1010700 HMA 2A - 1010710

Aluminum HMA 2 - 1010800 HMA 2A - 1010810

12" Straight with

2" NPT Back Inlet Cast Iron

HMA 2 -1060700 HMA 2A - 1060710

Aluminum HMA 2 - 1060800 HMA 2A - 1060810

12.00"

Te e

Cast Iron HMA 2 -1080700 HMA 2A - 1080710

Aluminum HMA 2 - 1080800 HMA 2A - 1080810

Ell

Cast Iron HMA 2 -1070700 HMA 2A - 1070710

Aluminum HMA 2 - 1070800 HMA 2A - 1070810

8.63"

10.47"

Caution:

Under no circumstances are the HMA-2 bafﬂ es and the HMA-2A bafﬂ es 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.

12.00"

6.00"

8.63"

10.47"

2" Straight

8.22"

6" Straight

4.11"

6" Straight with

2" NPT Back Inlet

6.00"

12" Straight

12.00"

8.63"

11.38"

2" NPT

Inlet

12" Straight with

2" NPT Back Inlet

Figure 6 - Burner Sections - Assembly

Midco International Inc.

2" NPT

Inlet

6.00"

8.63"

11.38"

Tee Section

10.11"

Elbow

Section

6.00"

8.63"

10.47"

8471 34

Page 15

Parts - Pilot Conﬁ guration & Mounting

1190800

Spark Rod &

Flame Rod

Direct Spark

1220800 Remote

Flame Rod

1200300

Spark Rod

and UV

1200350

Spark Rod

and UV

Brute Pilot

1240800

Remote UV

2.96"

1210800

Pilot with Spark

Rod Only

1190850

Spark Rod &

Flame Rod

Brute Pilot

5.57"

3.72"

Brute Pilot - w/ Spark Rod

1190850

1/8"

5.57"

3.72"

Brute Pilot - UV Scanner Mount

1200350

Location of First Burner Port Plug - See Installation, Burner Setup Section or Trouble Shooting Section (Used on high fire start systems ONLY)

5.57"

3.72"

0.65"

2.96"

8471 34

Pilot Detail - Spark Gap Measurement

Brute Pilot

1190850

Figure 7 - Pilot Conﬁ guration

Midco International Inc.

Page 16

Parts - Isometric View - HMA 2 & HMA 2A

2” Straight

Ell Section

Tee Section

6” Straight

12” Straight

Figure 8 - Typical Burner Assembly Parts - Isometric View

Midco International Inc.

1 11

8471 34

Page 17

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

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″ Bafﬂ e 1355-55 2

3 HMA Pilot End Plate 1354-60 Select the correct required end plates

4 Blank End Flange 1372-02 Select the correct required end plates

5 Mounting Bracket 1130100 2 2 2 2 2 2 3

6 HMA-2A 6″ Bafﬂ e 1395-23 2 2 4 4 2 2

7 HMA-2A Outside

Corner Bafﬂ e 1395-35 1

8 HMA-2/2A Tee Bafﬂ e 1395-11 1 2

9 Elbow Casting Section * See above listing for proper selection

10 Inside Bafﬂ e 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 Bafﬂ e 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 Conﬁ guration (For selection)

19 5/16-18 x 2″ Hex

Head Cap Screw Hardware 3 3 3 3 3 3 6

20 Inlet Flange (Tapered) 1352-02 (Select the correct required end plates

21 Bafﬂ e 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

Straight Straight Back Inlet Straight Back Inlet Section Section

Burner Conﬁ gurations: see page 14 for complete burner sections

Table 5 - Burner Assembly Parts

8471 34

Midco International Inc.

Page 18

Burner Assembly Instructions

Figure 9 - Typical HMA 2 & HMA 2A 6″ Direct Fire Burner Assembly

Figure 9 shows the assembly of a typical HMA 2 and HMA 2A direct ﬁ red burner assembly for both “in ﬁ eld” and factory assembly line.

A) 1-1/2″ Inlet Flange With Pilot Mount or Blank Plate Hardware Required:

Furnace Cement 8 Stainless Steel Pcs of 10-24 X 3/8″ Slotted Round Head Screw, 10-24 Hex Nut, 10-24 Lock Washer or S62 Stainless Steel Rivet Body (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 8 Stainless Steel Pcs of 10-24 X 3/8″ Slotted Round Head Screw, 10-24 Hex Nut, 10-24 Lock Washer or S62 Stainless Steel Rivet Body (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

(See Notes # 1)

Notes:

1) Furnace cement is to be applied between the casting and either blank plate, pilot plate and end ﬂ anges only, not between bafﬂ es and end plates.

2) The hardware listed on instructions A and B applies to each end of any size burner with such conﬁ guration.

3) For deﬁ nition and views of burner section, plates, ﬂ anges, 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 ﬂ ame exit.

5) In the absent of a rivet gun, use the hardware speciﬁ ed 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 ﬂ ange. UNDER NO CIRCUMSTANCES SHOULD THEY BE INSTALLED

BETWEEN THE FLANGE AND THE BURNER CASTING.

___________________________________

Midco® International Inc. - 4140 West Victoria Street - Chicago, Illinois 60646 - toll free: 866 705 0514

tel: 773.604.8700 - fax: 773.604.4070 - web: www.midcointernational.com - e-mail: sales@midcointernational.com

1113

8471 34

Printed in USA