LAARS Mighty Max VW User Manual

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Installation, Operation and Maintenance Instructions Document 2064D

Installation, Operation and Maintenance Instructions for

Mighty Max

Volume Water Heaters

Model VW Sizes 320M - 400M

U.S. Reg. 1,901,192 Canada Reg. 433,882

OUT OF

FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician, qualified in hot water heater installation and maintenance. Improper installation and/or operation could create carbon monoxide gas in flue gases which could cause serious injury, property damage, or death. Improper installation and/or operation will void the warranty.

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If the information in this manual is not followed exactly, a fire or explosion may result causing property damage, personal injury or loss of life.

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 call your gas supplier from a nearby phone. 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 gas supplier.

WARNING

Assurez-vous de bien suivres les instructions données dans cette notice pour réduire au minimum le risque d’incendie ou d’explosion ou pour éviter tout dommage matériel, toute blessure ou la mort.

Ne pas entreposer ni utiliser d’essence ni d’autres vapeurs ou liquides inflammables dans le voisinage de cet appareil ou de tout autre appareil.

QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:

• Ne pas tenter d’allumer d’appareils.

• Ne touchez à aucun interrupteur. Ne pas vous servir des téléphones dansle bâtiment où vous vous trouvez.

• Appelez immédiatement votre fournisseur de gaz depuis un voisin. Suivez les instructions du fournisseur.

• Si vous ne pouvez rejoindre le fournisseur de gaz, appelez le sservice des incendies.

L’installation et l’entretien doivent être assurés par un installateur ou un service d’entretien qualifié ou par le fournisseur de gaz.

AVERTISSEMENT

H0192500D

A subsidiary of BRADFORD WHITE Corporation

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LAARS Heating Systems

TABLE OF CONTENTS

SECTION 1. General Information

1.1 Introduction................................................... 3

1.2 Warranty ....................................................... 3

1.3 Technical Assistance .................................... 3

SECTION 2. Installation Instructions

2.1 General Information ...................................... 3

2.2 Heater Placement ......................................... 4

2.3 Installation of Outdoor Heaters ..................... 4

2.4 Freeze Protection ......................................... 4

2.5 Installation of Indoor Water Heaters ............. 4

2.6 Gas Supply and Piping ................................. 5

2.7 Water System Piping .................................... 6

2.7.1 Water Chemistry ........................................... 6

2.7.2 Water Piping ................................................. 6

2.7.3 Pressure Buildup in Water System ............... 7

2.7.4 Temperature and Pressure Relief Valve ...... 7

2.7.5 Pump Requirements ..................................... 7

2.7.6 Combined Space Heating/Potable

Water Heating Systems ................................ 8

2.8 Venting and Combustion Air Information ...... 9

2.9 Top-to-Rear Vent Collar Conversion ............ 9

2.10 Venting ......................................................... 9

2.10.1 Vertical Venting - Category I......................... 9

2.10.2 Vertical Venting - Non Category I ................. 9

2.10.3 Horizontal Venting - Non Category I ........... 10

2.10.4 Side Wall Vent Terminal ............................. 10

2.11 Air for Combustion and Ventilation ............. 13

2.11.1 Air From Room ........................................... 13

2.11.2 Ducted Combustion Air .............................. 14

2.11.3 Conversion for Ducted Combustion Air ...... 14

2.11.4 Combustion Air Piping ................................ 14

2.12 Electrical Wiring .......................................... 15

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SECTION 3. Operation

3.1 Start Up Requirements ............................... 17

3.2 Hi-Limit Checkout ....................................... 18

3.3 Venturi and Gas Pressure

Regulator System ....................................... 18

3.3.1 Overall Operation ....................................... 18

3.4 To Start Up System .................................... 18

3.4.1 Setting Temperature Controls .................... 19

3.5 To Shut Down System ................................ 19

3.6 Venturi Adjustment - Natural Gas ............... 19

3.6.1 Pressure Measurement Port ...................... 19

3.6.2 Adjustment Procedure - Natural Gas.......... 19

3.6.3 Venturi Setup Procedure - Natural Gas ...... 21

3.7 Venturi Adjustment - Propane Gas ............. 21

SECTION 4. Maintenance

4.1 General Instructions ................................... 22

4.2 Heater Exchanger ...................................... 22

4.2.1 Inspection of the Heat Exchanger .............. 23

4.2.1a External Heat Exchanger Inspection .......... 23

4.2.1b Internal Heat Exchanger Inspection ........... 23

4.2.1c Cleaning the Heat Exchanger - External .... 23

4.2.1d Cleaning the Heat Exchanger - Internal ..... 24

4.3 Gas and Electric Controls ........................... 24

4.4 Filter ........................................................... 24

4.4.1 Filter Function ............................................. 24

4.4.2 Filter Service .............................................. 24

SECTION 5. Troubleshooting

5.1 Sequence of Operation .............................. 24

5.2 Venturi and Gas Pressure Regulator

System ....................................................... 26

5.3 Electrical Components ............................... 26

5.3.1 General Troubleshooting ............................ 26

5.3.2 Electrical Troubleshooting .......................... 27

SECTION 6. Parts List for Mighty Max VW Heater

6.1 General Information .................................... 27

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Mighty Max Volume Water Heater

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SECTION 1. General Information

1.1 Introduction

This manual provides installation, operation, and maintenance instructions for the Mighty Max Volume Water Heater, Model VW, Sizes 320M and 400M. Review all application and installation procedures completely before proceeding with the installation. Consult the local factory representative or Laars factory with any questions regarding this equipment. Experience has shown that most operating problems are caused by improper installation. The VW heaters are offered in an indoor version and an outdoor version (see Figure 1). Table 1 lists the input/output ratings for each heater size.

The indoor version is convertible for outdoor use with the installation of a conversion kit (see Section 6, Parts List, for part number).

1.2 Warranty

The Mighty Max VW heaters are sold with a limited factory warranty. Details are specified on the back cover of this manual.

Make all warranty claims to an authorized Laars representative or directly to the factory. Claims must include the heater serial number and model number (this information can be found on the rating plate), installation date, and name of the installer. Shipping costs are not included in the warranty coverage.

packages. Inspect everything for damage immediately upon delivery, and advise the transporter of any shortages or damage. Any such claims should be filed with the transporter. The transporter will not accept a claim from the shipper, Laars.

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Some accessory items are shipped in separate

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The warranty does not cover damage caused by

improper installation, operation, or field modification.

1.3 Technical Assistance

Consult the local factory representative or Laars factory with any questions regarding the specification, installation, and operation of Laars equipment. An experienced technical support staff is ready to assist in assuring the proper performance and application of Laars products.

Heater Input Output

Size BTU/h kW BTU/h kW

320M 320,000 94 272,000 80

400M 399,000 117 339,150 99

Table 1. Input/Output Ratings.

SECTION 2. Installation Instructions

2.1 General Information

Install the Mighty Max VW heater in accordance with the procedures in this manual (or the Laars warranty may be voided), local codes, and ordinances. In the absence of such codes, install the heaters in accordance with the latest edition of the National Fuel Gas Code, ANSI Z223.1/National Fire Protection Association (NFPA) 54. In Canada, the installation must be in accordance with CSA B149.1 and local codes. The authority having jurisdiction may require the installation be in accordance with the American Society of Mechanical Engineers (ASME) Safety Codes for Controls and Safety Devices for

INDOOR OUTDOOR

Front Side

(Water Connections)

Figure 1. Mighty Max VW Heater Configuration.

Rear Side

(Opposite Water

Connections)

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LAARS Heating Systems

Automatically Fired Heaters, CSD-1. In Canada, other standards may apply. Any changes to the heater, its gas controls, gas orifices, or wiring may void the warranty. If field conditions require change, consult the factory.

The Mighty Max VW heater is designedcertified for installation on a combustible floor, if a non-combustible base is first placed under the heater.

Do not install the heater directly on carpeting

without placing a metal or wood panel between the carpeting and the heater. The metal or wood panel must extend beyond the full width and depth of the heater by at least 3 inches (76.2mm) in all directions. If the heater is installed in a carpeted alcove, the entire floor of the alcove must be covered by the metal or wood panel. The panel must be strong enough to carry the total weight of the heater and all piping, pumps, and any other equipment attached to the heater.

Clearance Indoor Outdoor From Combustibles Inches mm Inches mm

Top 18 457 Unobstructed

Water Conn. Side 12 305 12 305

Opposite side 6 152 6 152

Front Alcove Unobstructed

Rear 6 152 6 152

Vent *6

Flooring Combustible Combustible

Service clearance = 24 inches (610mm) at front of heater. *1" (25mm) if double wall vent is used.

Table 2. Minimum Heater Clearances

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From Combustible Surfaces.

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* 152 —

2.2 Heater Placement

Locate the heater to provide adequate clearances on all sides for maintenance and inspection. There must also be minimum distances maintained from combustible surfaces (see Table 2). The heater must be isolated or otherwise protected from any source of corrosive chemical fumes, such as trichlorethylene, perchlorethylene, chlorine, etc. Install the heater so that the gas ignition system components are protected from water (drippings, spraying, rain, etc.) during operation and service.

2.3 Installation of Outdoor Heaters

CAUTION

Outdoor installations are not recommended in areas where the danger of snow blockage exists.

AVERTISSEMENT

L’eau chaude peut brûler ! L’eau chaude peut causer des brûlures du troisième degré en 6 secondes à 60°C (140°F) et en 30 secondes à 54°C (130°F).

1. Locate the heater to provide at least the minimum clearances as listed in Section 2.2, “Heater Placement.” VW heaters require an outdoor terminal kit when installed outdoors (see Section 6, Parts List).

2. Do not locate the heater in an enclosure or throughwall recess. Avoid locations where wind deflection off structures might cause down-draft. When such wind conditions are possible, locate the heater at least 3 feet (.9m) from structures.

3. Never install the heater under any kind of roof overhang. Do not locate the heater below or adjacent to any doors, windows, louvers, grills, etc. which communicate in any way with an inhabited area of a building, even though such communication might be through another structure such as a garage or utility room (see Figure 2).

Figure 2. Incorrect Installation of Boiler.

2.4 Freeze Protection

Although Mighty Max VW heaters are design-

certified for outdoor installations, such installations are not recommended in areas subject to freezing temperatures, unless proper precautions are taken.

Power outage, interruption of gas supply, failure

of system components, activation of safety devices, etc., may prevent a heater from firing. Any time a

heater is subjected to freezing conditions, and the heater is not able to fire, and/or the water is not able to circulate, there is a risk of freezing in the heater or in the pipes in the system. When water

freezes, it expands. This can result in bursting of pipes in the system, or damage to the heater, which could result in leaking or flooding conditions.

Contact the local factory representative or Laars

for additional information.

2.5 Installation of Indoor Water Heaters

Combustion Air Supply and Ventilation:

There are a variety of options available to the

installer when it comes to venting and combustion air; venting can be vertical or horizontal, it can originate at

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Mighty Max Volume Water Heater

Distance from Gas Meter or Last Stage Regulator

0-100 feet 100-200 feet 200-300 feet

0-30m 30-60m 60-90m

Natural Propane Natural Propane Natural Propane

Size in. mm in. mm in. mm in. mm in. mm in. mm

320M 1.25 32 1.25 32 1.50 38 1.25 32 1.50 38 1.50 38

400M 1.25 32 1.25 32 1.50 38 1.25 32 2.00 51 1.50 38

Notes: 1. These numbers are based on 1/2 inch (13mm) water column pressure drop.

2. Check supply pressure and local code requirements before proceeding with work.

3. Pipe fittings must be considered when determining gas pipe sizing.

Table 3. Natural Gas and Propane, Pipe Size Requirements.

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the top of the heater or the back, and combustion air can be obtained from the room where the heater is installed or ducted directly to the heater from outdoors (see Sections 2.8 through 2.11 for details).

Air Shutter Enclosure

Filter Housing

Automatic, Regulator and Redundant

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Gas Valve

Venturi

Mixture Plenum

NOTE: The above diagram is a representation, actual venturi assembly may vary depending upon heater size.

OUT OF

Blower Motor

SIZES:

320M, 400M

with CSA B149.1 and all local codes that apply (see Figure 3 for heater gas valve arrangement).

2. Check the rating plate to make sure the heater is fitted for the type of gas being used. Laars heaters are normally equipped to operate below a 2000 foot (610m) altitude. Heaters equipped to operate at high altitudes have appropriate stickers or tags attached.

3. The figures in Table 3 should be used to size the gas piping from the gas meter to the heater. Check local codes for BTU/h capacity required.

4. Install a sediment trap (drip leg) ahead of the gas controls (see Figure 4). Fit the trap with a threaded cap which can be removed for cleaning.

5. When required by code, install a second manual gas shutoff valve. Do not remove manual shutoff valve supplied with the heater.

6. Disconnect the heater and its individual shutoff valve from the gas supply piping system during pressure testing of the system at pressures higher than 1/2 psi (3.5 kPa). Isolate the heater from the gas supply piping system by closing its individual manual gas shutoff valve during any pressure testing of the gas supply piping system at test pressures equal to or less than 1/2 psi (3.5 kPa).

7. Gas supply pressures to the heater are listed in Table 4.

Figure 3. Heater Gas Valve Arrangement.

2.6 Gas Supply and Piping

Review the following instructions before

continuing the installation.

1. Gas piping installation must be in accordance with the latest edition of ANSI Z223.1/NFPA 54. In Canada, the installation must be in accordance

Supply Pressure Natural Gas Propane Gas Water Column

Minimum 5 127 9 229

Maximum 9 229 14 356

Table 4. Gas Supply Pressure Requirements.

in. mm in. mm

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LAARS Heating Systems

NOTE: The heater and all other gas appliances sharing the heater gas supply line must be firing at maximum capacity to properly measure the inlet supply pressure. Low gas pressure could be an indication of an undersize gas meter and/or obstructed gas supply line.

8. Do not exceed the maximum inlet gas pressures specified. Excessive pressure will result in damage to the heater's gas controls. The minimum pressures specified are for gas input adjustment.

9. The correct differential gas pressure is stamped on the rating plate. The regulator is preset at the factory, but may need adjustment for altitude per Section 3.

10. Before operating the heater, test the complete gas supply system and all connections for leaks using a soap solution.

CAUTION

Since some leak test solutions (including soap and water) may cause corrosion or stress cracking, rinse the piping with water after testing.

ATTENTION

La commande d’allumage fonctionne sur un courant de 120V. Pensez-y lorsque vous travaillez sur le chauffe-eau et prenez soin d’éviter tout contact avec des pièces branchées sur le courant qui causeraient une électrocution, conduisant à des dégâts matériels, aux blessures voire à la mort.

OUT OF

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Gas Supply Inlet

Te e Fitting

3 in. (76mm) Min.

Figure 4. T-Fitting Sediment Trap Installation.

up a heat exchanger tube-cleaning maintenance schedule to prevent heat exchanger tube cracking and wear. Not fixing the condition may cause serious damage to the heater and the water system.

Scaling is a layer on the inner surface of the heat exchanger tubes which restricts the flow of water. Scale can be any color or texture, smooth or rough, granular or amorphous. Erosion is usually identified by pitting, cavitation, ridges and “islands” on the inner surfaces of the heat exchanger tubes. If this is caused by extremely soft water, or a water softener in the system, the internal copper surfaces will be very shiny. Other chemicals, such as chlorine or chlorides in the water, will cause dark patches of erosion.

NOTE: Laars does not warrant heat exchangers damaged by scaling, corrosion, or erosion.

Nipple

Cap

To Equipment Inlet

2.7 Water System Piping

2.7.1 Water Chemistry

Laars equipment is designed to be used in a variety of water conditions. The water velocity in the heat exchanger tubes is kept high enough to prevent scaling from hard water, yet low enough to avoid erosion by soft water. The water in 95 percent of the urban centers in the United States is compatible with this equipment, but in some areas a water supply will contain a large quantity of scaling chemicals or the water may be extremely soft or erosive. In rare situations the water will contain both scaling chemicals and erosive chemicals such as calcium or sodium chloride. These conditions may be caused by well water or a nearby pumping station, and the particular condition may not be characteristic of the entire city water system.

NOTE: It is possible to have hard and soft water in the same city. Check with the local water company.

If an installer sees damage to any water handling equipment at the installation site, it should be repaired as soon as possible to help reduce maintenance costs. If there is erosion, resize the pump to reduce water velocity before the tube ruptures. If scaling is bad, set

2.7.2 Water Piping

Minimum inlet water temperature is 120°F

(49°C).

VW heaters are intended for heating large volumes of water at constant flow rates, usually for storage in a tank. Heaters in this type of application are sometimes called circulating water heaters.

Figure 5 shows the VW heater with tank and two pumps. One pump (recirculation) only circulates the hot water through the building plumbing. The other pump (heater) circulates water between the tank and the heater. This heater circulating pump is essential for proper operation of the heater (see Section 2.7.5).

The heater circulating pump must be sized to provide enough flow to prevent damage to the heat exchanger, and must handle the hardness or softness of the water being heated. Generally, hard water must be pumped at higher velocity; however, soft water will erode holes in the heat exchanger tubing if pumped too fast.

The Mighty Max VW heater comes standard with copper tubes, but in areas where the water supply is soft or corrosive, the heat exchanger should be factory ordered with cupronickel tubes. Consult the

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Mighty Max Volume Water Heater

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local factory representative or Laars factory for additional information.

2.7.3 Pressure Buildup in Water System

The water utility supply meter may contain a check valve, back flow preventer, or water pressure reducing valve. This will create a closed water supply system. Contact the water supplier or local plumbing inspector on how to control this situation.

During the heating cycle of the heater, the water expands creating a pressure buildup in the water system. The pressure and temperature relief valve may discharge hot water under these conditions, causing a loss/waste of energy and a buildup of lime on the relief valve seat.

NOTE: Do not plug the relief valve.

There are two methods to prevent the water heater pressure relief valve from discharging hot water in a closed water system:

1. Install a pressure relief valve on the cold water

supply line. Make sure that the discharge of this

valve is directed to an open drain and protected

from freezing.

2. Install a properly sized thermal expansion tank

on the cold water supply line.

2.7.4 Temperature and Pressure Relief Valve

For protection against excessive pressure, the

water heater is equipped with a pressure relief valve.

storage vessel, a temperature and pressure relief valve must be installed on the storage vessel. The temperature and pressure relief valve must be designcertified by a nationally recognized testing laboratory that maintains periodic inspection of listed equipment or materials, in accordance with the requirements of the standard for Relief Valves for Hot Water Supply Systems, ANSI Z21.22 / CSA 4.4.

have a BTU/h (kW) capacity rating that is greater than the BTU/h (kW) input of the water heater. The temperature and pressure relief valve must be marked with a maximum working pressure not to exceed the maximum working pressure shown on the rating plate of the water heater, or the maximum working pressure of the separate storage vessel, whichever is the lower pressure. The temperature and pressure relief valve must have a maximum working temperature not to exceed 210°F (99°C).

temperature and pressure relief valve and the storage vessel.

quantities should circumstances demand.

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When the water heater is connected to a separate

The temperature and pressure relief valve must

Do not place any shutoff valves between the

The relief valves discharge water in large

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The discharge pipe:

1. Must not be connected directly to a drain. The Discharge pipe must terminate 6 inches (152mm) above a floor drain or external to the building. If the discharge pipe is not directed to a drain or other suitable means, the water flow may cause property damage.

2. Must not be smaller than the pipe size of the relief valve.

3. Must be of material capable of withstanding 210°F (99°C) without distortion.

4. Must be installed to allow complete drainage of both the relief valve and discharge pipe.

5. Must not have any valve between the relief valve and the end of the discharge pipe. Do not thread, cap, plug, or block the end of the

discharge pipe. Do not install a reducing coupling or other restrictions in the discharge pipe.

WARNING

Hot water can scald! Hot water can produce third degree burns in 6 seconds at 140°F (60°C) and in 30 seconds at 130°F (54°C).

ATTENTION

Au moment de l’entretien des commandes, mettez des étiquettes sur tous les fils avant de les débrancher. Des erreurs de câblage peuvent causer un fonctionnement inadéquat et dangereux. Vérifier que tout fonctionne bien après votre entretien.

Manually operate the relief valves at least once a

year. To prevent water damage, discharge pipe must terminate at an adequate drain. Standing clear of the outlet (discharge water may be hot), lift and release the lever handle on the relief valve to make the valve operate freely.

2.7.5 Pump Requirements

Table 5 specifies water flow rates for the

Mighty Max VW heaters, and the pumping head required for typical piping configurations. Table 5 allows for 30 feet (9.1m) of piping and typical fittings (see Figure 5). Piping with a shorter length or larger diameter may reduce the head requirement and pump power consumption. Contact a Laars representative for assistance.

The correct flow rate can be verified by checking

the temperature rise of water as it passes through the heater. To check the temperature rise, measure the difference in water temperature between the heater inlet and outlet to determine flow. For example: If a Size 320M VW heater is installed and normal water is used; the inlet water temperature is 160°F (71°C); the outlet water temperature is 171°F (77°C). Then there is a 11°F (6°C) degree temperature rise. Per Table 3,

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LAARS Heating Systems

Hot Water To Bldg.

To Drain

Mighty Max VW Heater

Thermal Expansion Tank

Cold Water

Hot Water Return From Bldg.

NOTE: Intermittent pump must be used with EM2 and remote temperature control.

Figure 5. Water Piping Diagram.

this is essentially correct for normal water. If a higher temperature rise is measured, flow must be increased by changing the piping or pump.

2.7.6 Combined Space Heating/Potable

When using the Mighty Max VW heater as a source of heat for a combined space heating/potable water heating system, be sure to follow the instructions of the space heating system.

Do not use water piping, fittings, valves, pumps, and any other components which are not compatible with potable water.

Do not connect the heater, which will be used to supply potable water, to any heating system or components previously used with a nonpotable water heating system.

Do not add boiler treatment or any chemicals to the heating system piping, since the piping contains water for potable use.

Do not use solder containing lead in the potable water lines.

If the space heating system requires water temperatures greater than the water temperature for potable hot water use, a tempering valve (see Figure 6)

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Water Heating Systems

OUT OF

Conventional Tank

Service Valve

To Drain

Mixing Valve

Hot Water

From Water Heater

or Storage Tank

Figure 6. Installation of Tempering Valve.

or other means should be installed in the potable hot water supply line to limit the risk of scald injury.

Some jurisdictions may require a backflow preventer in the cold water line. In such cases, the temperature and pressure relief valve may discharge water due to expansion. An expansion tank approved for potable water will eliminate this condition. Follow the manufacturer's instructions for installation of the expansion tank.

Pump

KEY

Valve

Check Valve

Gauge

Out Mixed Water For Potable Use

Cold Water

Supply

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Mighty Max Volume Water Heater

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2.8 Venting and Combustion Air Information

Provisions for venting and supply of air for

venting and combustion must be done in accordance with these instructions and applicable requirements of the latest edition of ANSI Z223.1/NFPA 54. In Canada, installation must be in accordance with CSA B149.1, and applicable local codes.

There are a variety of ways to provide venting

and combustion air for the VW heater (see Figure 7).

The Mighty Max VW heater is certified as a true

direct vent unit when installed according to the instructions for horizontal venting and ducted combustion air. This can be done even if the runs are vertical.

2.9 Top-to-Rear Vent Collar Conversion

The Mighty Max VW heater is shipped with the

vent collar on top of the heater. Follow this procedure to convert it for rear connection (see Figure 8).

1. Remove the adapter plate from the top panel.

2. On the heater jacket, remove the top panel and ease its lip from under the edge of the bonnet to gain access to the flue collector.

3. Remove the vent collar/stack from the flue collector. Do not damage the vent collar/stack during removal.

4. Remove the blank plate from the rear of the heater jacket.

5. Remove the blank plate from the rear section of the flue collector. Be careful not to lose the

PRODUCTION

insulation attached to the plate.

6. Apply high temperature sealant and install the blank plate (previously removed from the rear section of the flue collector) on top of the flue collector.

7. Install the blank plate (previously removed from the rear of the boiler jacket) over the stack opening on the top panel of the boiler.

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8. Apply high temperature sealant (see Table 6) to vent/collar stack and install on the rear of the flue collector.

9. Slip the adapter plate over the vent collar/stack and install it onto the rear heater jacket (see Figure 8).

2.10 Venting

Venting must be in accordance with these

instructions and applicable requirements of the latest edition of ANSI Z223.1/NFPA 54. In Canada, installation must be in accordance with the latest edition of CSA B149.1, and applicable local codes.

2.10.1 Vertical Venting - Category I

The Mighty Max VW heater has a “fan-assisted”

combustion system, so vertical vents must be installed in accordance with the special code requirements for Category I - Fan-Assisted Appliances. These requirements can be found in the latest edition of ANSI Z223.1/NFPA 54; Chapters 10 & 13 may be referenced. In Canada, CSA B149.1 should be used for guidance. These codes permit installation as a single appliance or in combination with other Category I appliances. However, there are very important requirements for minimum and maximum vent diameter and length. Make sure vertically-vented installations comply with these codes.

NOTE: If a vent cannot be installed in accordance with the requirements of these codes, it must be installed as a horizontal vent, even if it is mainly vertical.

2.10.2 Vertical Venting - Non-Category I

When venting does not meet the code

requirements for Category I - Fan-Assisted Vertical Vents, it can develop positive pressure. Such venting must be installed in accordance with this section or Section 2.10.3.

Soft or Normal Water Hard Water

Pipe Size Flow Headloss Temp, Rise Flow Headloss Temp. Rise

Model in. mm gpm L/m ft. m °F °C gpm L/m ft. m °F °C

0320M 1.5 38 51 193 25.9 8 10.5 6 68 257 46.0 14 7.9 4

2.0 51 51 193 13.9 4 10.5 6 68 257 24.7 8 7.9 4

0400M 1.5 38 51 193 26.0 8 13.1 7 68 257 46.3 14 9.8 5

2.0 51 51 193 14.1 4 13.1 7 68 257 25.0 8 9.8 5

Notes: 1. Pressure dop includes allowance for 30 feet 9.1m of piping and normal fittings. If piping is shorter or of larger

diameter, pump power may be reduced substantially. Contact Laars Representative for assistance.

2. Heaters for soft water application should be equipped with cupronickel heat exchangers. Soft Water: 0 to 7.5 Grains/gallon Normal Water: 7.5 to 17 Grains/gallon Hard Water: More than 17 Grains/gallon

3. The temperature rise across the heater should never exceed 20°F (11°C). Minimum inlet water temperature is

120°F (49°C).

Table 5. Pump Requirements for Mighty Max VW Heaters.

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Term Description

Pipe Must comply with UL Standard 1738

such as type 29-4C stainless steel

Joint Sealing Follow vent manufacturer's

instructions

Insulation Recommended, but not required,

minimum R5 with protective cover

Table 6. Required Horizontal Venting Material.

The following requirements must be used for

Non-Category I venting:

1. Laars specified vent pipe material (Table 6) and sizes (Table 7).

2. Pipe insulation and sealing tape.

3. Routing vent pipe through spaces which, except for the terminal, remain above 60°F (16°C) during heater operation.

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2.10.3 Horizontal Venting - Non-Category I

When venting is horizontal, or cannot meet the

code requirements for Category I - Blower-Assisted Vertical Vents, it can develop positive pressure and must be installed in accordance with this section.

The following requirements must be used for

Horizontal Venting - Non-Category I:

1. Laars specified vent piping materials (Table 6) and sizes (Table 7).

2. Laars side wall vent hood.

3. Pipe insulation and sealing tape.

4. Routing vent pipe through spaces which, except for the terminal, remain above 60°F (16°C) during heater operation.

2.10.4 Side Wall Vent Terminal

The side wall vent hood must be used when the

heater is vented through a side wall. It provides a means of installing vent piping through the building wall, and must be located in accordance with ANSI Z223.1/NFPA 54 and applicable local codes. In Canada the installation must be in accordance with CSA B149.1 and local applicable codes (see Figure 9). Consider the following when installing the terminal:

1. Locate the vent terminal so that it will not be damaged by pedestrians and other traffic, and so the discharge is not objectionable. The National Fuel Gas Code requires a through-wall vent terminal be at least 7 feet (2.1m) above grade if located at a public walkway.

2. Locate the vent terminal so that vent gases cannot be drawn into air conditioning system inlets. The National Fuel Gas Code requires that

PRODUCTION

LAARS Heating Systems

it be at least 6 feet (1.8m) above any such inlet that is within 10 feet (3m).

3. Locate the vent terminal so that vent gases cannot enter the building through doors, windows, gravity inlets or other openings. The National Fuel Gas Code requires that it be located at least 4 feet (1.2m) below, 4 feet (1.2m) horizontally from, or 3 feet (0.9m) above such openings.

4. Locate the vent terminal so that it cannot be blocked by snow. The National Fuel Gas code requires that it be at least 12 inches (305mm) above grade, but the installer may determine it should be higher depending on local conditions.

5. Locate the terminal so the vent exhaust does not settle on building surfaces and other nearby objects. Vent products may damage such surfaces or objects. But the actual construction of the vent terminal and the flow of vent products must not be altered.

6. Locate the terminal at least 6 feet (1.8m) horizontally from any gas or electric metering, regulating, or relief equipment, or building opening.

Mighty Max units are Category I fan-assisted

when vented vertically and adhering to all applicable codes. Mighty Max units are not allowed to be vented into a common horizontal vent system, unless a properly-sized vent fan is used, and the common vent system is properly designed by the vent fan manufacturer or a qualified engineer.

When common venting Mighty Max fan-assisted

heaters with other appliances through one shared vertical duct called a “common vent”, special care must be taken by the installer to ensure safe operation. In the event that the common vent is blocked, it is possible, especially for fan-assisted devices, to vent backwards through non-operating appliances sharing the vent, allowing combustion products to infiltrate occupied spaces. If the appliances are allowed to operate in this condition, serious injury or death may occur.

WARNING

Operation of appliances with a blocked common vent may lead to serious injury or death. Safety devices must be implemented to prevent blocked common vent operation. If safe operation of all appliances connected to a common vent cannot be assured, including prevention of spillage of flue gasses into living spaces, common venting should not be applied, and appliances should each be vented separately.

Page 11

Mighty Max Volume Water Heater

Category I

Vertical Venting (Category I)

Screen Provided

On Vertical Intake

Air Terminal

Combustion Air In

Through Louvers

Page 11

For vertically ducted combustion air:

• Combustion air intake must terminate at least 3 feet (0.91m) lower than vent termination, if it is located within a 10 foot (3.05m) radius.

• Combustion air intake must be at least 1 foot (0.3m) above roof top and normal snow levels.

OUT OF

Vertical Venting

with Ducted

Combustion Air

Non-Category I

PRODUCTION

Exhaust Terminal Detail

Horizontal Venting

Any Vent Which Does Not Meet

Category I Combustion Air

Through Louvers

Side View

Horizontal

Intake Terminal Detail

(Combustion Air)

Wall

Horizontal Venting

Ducted Combustion Air

(Certified As Direct Vent)

NOTE: All views are shown

from rear of heater

Figure 7. Venting and Combustion Air Options.

Wall

Side View

Page 12

LAARS Heating Systems

Vent

Collar/Stack

Blank Plate

(Heater Jacket)

Adapter Plate

Top Panel

1. Removal of Blank Plate and Adapter Plate From Heater

OUT OF

Blank Plate On

Heater Jacket

Top Panel

Blank Plate On

Flue Collector

3. Blank Plate Placement Over Stack Top Opening

Blank Plate

(Flue

Collector)

Vent

Collar/Stack

PRODUCTION

2. Removal of Blank Plate From Rear of Flue Collector

Figure 8. Top-To-Rear Vent Collar.

Heater

Size of Elbows Vent Terminal Combustion Air

320M 6 152 50 15 5 D2004500 20260701 400M 7 178 50 15 5 D2004600 20260702

IMPORTANT: Maximum pipe length allowed is 50 feet (15m), regardless of the number of elbows. Maximum number of elbows allowed is 5. Vent pipe minimum clearance from combusible surfaces is 6 inches (152mm).

Pipe Diameter Max Pipe Length

in. mm ft. m

Max No. Side Wall Side Wall

4. Connecting Vent Collar/Stack to Flue Collector

Part Number Terminal Part Number

Table 7. Vent Piping Specifications (Combustion Air Exhaust).

Page 13

Mighty Max Volume Water Heater

Page 13

It is for this reason that, in addition to following proper vent sizing, construction and safety requirements from the National Fuel Gas Code, ANSI Z223.1 or in Canada, from CSA B149.1 as well as all applicable local codes, it is required that installers provide some means to prevent operation with a blocked common vent. It is suggested that a blocked vent safety system be employed such that if the switch from one appliance trips due to excessive stack spill or backpressure indicating a blocked vent condition, that all appliances attached to the vent be locked out and prevented from operating. (Note that the Mighty Max unit is equipped with a blocked vent safety (pressure) switch, as shipped.) As an additional precaution, it is recommended that a Carbon Monoxide (CO) alarm be installed in all enclosed spaces containing combustion appliances. If assistance is required in determining how a blocked vent safety system should be connected to a LAARS product, please call Applications Engineering at (603) 335-6300.

Refer to the installation and operating instructions on all appliances to be common vented for instructions, warnings, restrictions and safety requirements. If safe operation of all appliances connected to a common vent cannot be assured, including prevention of spillage of flue gasses into living spaces, common venting should not be applied, and appliances should each be vented separately.

OUT OF

2.11Air for Combustion and Ventilation

The heater requires air for combustion and the space around the heater requires ventilation. Combustion air can be provided by standard practices as specified in the installation codes (ANSI Z223.1/ NFPA 54, in Canada, CSA B149.1 and local applicable codes), or ducted directly to the heater. Ventilation air must be provided in either case.

2.11.1 Air From Room

Standard requirements for providing air for combustion and ventilation are provided by ANSI Z223.1/NFPA 54 and in Canada by CAN/CSA B149.1. These codes require passages be provided for air flow into the space where the heater is installed. The size of these passages is based on the firing rate of the heater and the path of air flow into the space. In general, installations which take air from inside the building require larger passages than those which take air directly through an outside wall.

Failure to provide adequate combustion and ventilation air can cause the heater, and other appliances occupying the same space, to operate with dangerous and inefficient combustion, and can cause overheating of the space. Be sure to provide air passages in accordance with ANSI Z223.1/NFPA 54, in Canada, CSA B149.1 and local applicable codes,

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Vent Terminal

4 ft. (1.2 m) Min.

Vent Terminal

3 ft. (0.9 m) Min.

4 ft. (1.2 m) Min.

Vent

Terminal

12 in. (305mm) Min.

Less Than

10 ft. (3.0 m)

6 ft. (1.8 m) Min.

Grade

Forced Air

Inlet

Figure 9. Building Exterior.

Page 14

and do not permit any other condition, such as an exhaust blower, to affect the air supply for combustion and ventilation.

2.11.2 Ducted Combustion Air

Combustion air can be brought directly to the heater through a duct of suitable size and length (see Table 7). Consult Laars about installations not covered by Table 7.

Combustion air must be taken from out-of-doors by means of the Laars side wall terminal. Locate the terminal within 10 feet (3m) of the heater vent exhaust terminal, but no closer than 3 feet (0.9m) (centerline distance).

Do not locate the air inlet terminal near a source of corrosive chemical fumes (e.g., cleaning fluid, chlorine compounds, etc.). Locate it so that it will not be subject to damage by accident or vandalism. It must be at least 7 feet (2.1m) above a public walkway.

Use single-wall galvanized pipe for the combustion air duct. Route the duct to the heater as directly as possible. Seal all joints with tape. Provide adequate hangers. The heater must not support the weight of the combustion air duct.

When combustion air is ducted to the heater, other provisions must be made for heater room ventilation. VW heaters lose less than 1 percent of their input rating to the room, but other heat sources may be present. Provide enough ventilation air to meet comfort specifications. Make sure the ventilation air is not directed at the heater, water piping or other equipment which could be damaged by freezing.

PRODUCTION

OUT OF

Louvered

Plate

Adapter

Plate

LAARS Heating Systems

Inlet Pipe

2.11.3 Conversion for Ducted Combustion Air

The conversion to ducted combustion air requires the parts listed in Table 8. Follow these procedures to convert the heater (see Figure 10):

Boiler Size Assembly Number

320 20258101

400 20258102

Table 8. Combustion Air Assembly.

1. Remove the louvered plate from the left side of

the heater.

2. Remove the adapter plate from the shipping

container.

3. Install the blower motor housing collar in gasket.

4. Slip one end of the inlet pipe over the collar on

the adapter plate.

5. Slide the inlet pipe and adapter plate into the

heater opening until the pipe is aligned with the

blower motor.

Ducted Combustion

Air Pipe

Figure 10. Ducted Combustion Air Conversion.

6. Slip the end of the inlet pipe over the blower motor housing collar.

7. Secure the adapter plate to the side of the heater with the 4 screws.

2.11.4 Combustion Air Piping

Run piping of the appropriate size between the

air intake terminal and the heater (see Table 7). Table 9 lists the materials for piping the heater.

Page 15

Mighty Max Volume Water Heater

Page 15

Term Description

Pipe Single-wall galvanized steel pipe,

24 gauge minimum.

Joint Sealing Permanent duct tape or aluminum

tape

Insulation Not required, but recommend R5

insulation for cold installations (consult American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) handbook

Table 9. Required Combustion Air Piping Material.

2.12 Electrical Wiring

WARNING

Electrically ground the heater in accordance with the latest edition of ANSI/NFPA 70. In Canada, use CSA C22.1. Do not rely on the gas or water piping to ground the metal parts of the heater. Often, plastic pipe or dielectric unions isolate the heater electrically. Service and maintenance personnel who work on or around the heater may be standing on wet floors and could be electrocuted by an ungrounded heater. Electrocution can cause serious injury or death.

La chaudière doit être mise à la terre selon les exigences officielles locales ou, en l’absence de toute instruction officielle, l’installation doit être conforme avec la dernière édition du Code électrique canadien CSA C22.1, Partie 1, au Canada. N’utilisez pas la tuyauterie de gaz ou d’eau pour mettre à la terre les parties métalliques de la chaudière. Les unions diélectriques ou avec tuyau en plastique peuvent isoler la chaudière électriquement. Les membres du personnel de service et d’entretien qui travaillent sur et autour de la chaudiére peuvent marcher sur des planchers mouillés et pourraient se faire électrocuter par une chaudière non mise à la terre.

PRODUCTION

OUT OF

AVERTISSEMENT

1. Check heater wiring and pump for correct voltage, frequency, and phase.

2. Wire the heater and pump exactly as shown in the wiring diagram supplied with the heater (see Figure 11).

3. Electrically interlock the pump and heater so the heater cannot come on unless the pump is running.

4. Connect all field-installed devices (relays, timers, temperature devices, etc.) to the heater wiring at points labeled “Field Interlock” (see Figure 11).

Page 16

LAARS Heating Systems

NEUTRAL

LIGHT

POWER ON

SCHEMATIC WIRING DIAGRAM

3 POS. SWITCH

HOT

PRODUCTION

LOW WATER

CUTOFF

P1234

CONNECTION DIAGRAM

LIGHT

POWER ON

TOGGLE

SWITCH

POWER SUPPLY

HOT

115V/60 Hz

PUMP

NEUTRAL

PUMP

XFMR

RELAY

LWCO

OUT OF

TEMPERATURE

115V 24V

TRANSFORMER

PUMP

CONDUCTOR

GROUNDING

SENSOR

TEMPERATURE

24V

COM

SENSOR

CONTROLLER

JUNCTION

GROUNDING

TIME

DELAY

6 1

432

COMBUSTION

24V

115V

FUSE

FUSIBLE

LINK

FUSIBLE

LINK

HIGH LIMIT

AUTO RESET

FAN

MANUAL RESET

FUSE

2 AMP

HIGH

AUTO.

RESET

HIGH

RESET

MANUAL

FUSIBLE

COM

24V

HIGH LIMIT

LIMIT

LINK

24VAC

IND

COM

PRE.P

CONTROL

TEMPERATURE

FS/S2

FLOW

SWITCH

JUMPER

FIELD

(REMOVE

INTERLOCK

IGNITION

CONTROL

MV1

P.SW

GND

IGNITER

WHEN

USED)

TH TR

SWITCH

PRESSURE

STACK

GAS VALVE

SWITCH

PRESSURE

IGNITION

CONTROL

TH GND L2

FS/S2

IND

MV1

GAS VALVE

VENTURI

DIFFERENTIAL

STACK

BURNER

TEMPERATURE

IGNITER

COMBUSTION

SWITCH

PRESSURE

SWITCH

PRESSURE

SWITCH

PRE.P

24VAC

FLOW

SWITCH

FAN

SWITCH

TEMP

BURNER

VENTURI

DIFFERENTIAL

APPLIANCE MATERIAL (105°C) OF EQUIVALENT GAUGES (AWG).

4. ELECTRICAL WIRING MUST BE IN ACCORDANCE WITHANSI/NFPA 70 AND THE LATEST EDITION OF CANADIAN ELECTRICAL CODE.

115V

5. IF ANY OF THE ORIGINAL WIRE AS SUPPLIED WITH THE APPLIANCE MUST BE REPLACED, IT MUST BE REPLACED WITH

FIELD WIRING

6. PUMP IS FIELD-SUPPLIED.

24V

115V

COLOR LEGEND

BK - BLACK

W - WHITE

R - RED

Y - YELLOW

BL - BLUE

BR - BROWN

O - ORANGE

G - GREEN

NOTES:

P - PURPLE

BR/Y - BROWN WITH YELLOW

BL/Y - BLUE WITH YELLOW

2. THE DENOTES OPTIONAL COMPONENTS.

3. REMOVE JUMPER WHEN USING FIELD INTERLOCK.

1. ALL WIRING TO BE 105°C, 600V WIRE RATING.

24V

FACTORY WIRING

Figure 11. Wiring Diagram.

Page 17

Mighty Max Volume Water Heater

OUT OF

PRODUCTION

Page 17

SECTION 3. Operation

WARNING

To avoid property damage, injury or loss of life, do not use this appliance if any part has been under water. Immediately call a qualified service technician to replace the appliance.

AVERTISSEMENT

N’utilisez pas cet appareil s’il a été en partie submergé. Appelez immédiatement un technicien qualifié pour remplacer l’appareil.

3.1 Start Up Requirements

Lighting: Safe lighting and other performance criteria were met with the gas manifold and control assembly provided on the boiler when it underwent tests specified in ANSI Z21.10.3 Standard.

Before placing the heater in operation, check the automatic safety shutoff devices. Once the heater is connected to the gas piping and after all of the requirements in Section 2 have been met, follow this procedure:

1. Before beginning the tests, make sure the main

manual gas valve, and any other boiler firing

valves, are in the OFF position.

NOTE: The gas valve is turned off as follows:

2. Press in gas control knob slightly and turn

3. Make sure the power switch on the heater is in

4. Normal Operating Sequence

NOTE: The manual gas valve must be ON for the burner to ignite. This valve is turned ON as follows:

clockwise to OFF. Knob cannot be turned unless

it is pushed in slightly. Do not force it.

the ON position. Reset all safety devices (high

limit, pressure switch, Low-Water-Cutoff, etc.).

When the circulation pump is running, the heater

will turn itself on and off in response to the water

temperature. When the water cools below the set

temperature, the following sequence occurs:

a. The aquastat powers the ignition control.

b. The ignition control turns on the

combustion fan. After about a 15 second pre-ignition purge, while the fan clears the combustion chamber, the igniter is turned on. The igniter takes about 25 seconds to heat up. You can see a glow through the view port (see Figure 12).

c. Turn counterclockwise to ON.

d. When the igniter is hot, the ignition control

turns on the gas valve and the burner

Front View of Boiler

Igniter

Junction

Box

NOTE: Sight glass location may vary.

Figure 12. Periodic Flame Observation.

ignites. You can see the burner flame through the view port (see Figure 12).

e. The heater operates until the aquastat

senses that the water is hot enough, and the burner shuts off. The combustion fan runs for about one minute to blow all combustion products out of the boiler.

If the igniter fails to ignite the burner in step 3 (for example, if there is air in the gas line), the ignition control shuts off the gas valve after a few seconds of operation. The purge and ignition sequence is automatically repeated. If there is no ignition in three tries, the ignition control “locks out” until the problem is corrected. Contact a qualified service technician.

Sight Glass

For Flame Observation

3.1 Critères de démarrage

Éclairage: L’éclairage ainsi que d’autres critères de sureté ont été verifiés avec les commandes de gaz installées sur la chaudière au cours des test effectués qui sont recommandés dans le ANSI Z21.13 Standard.

Avant de mettre la chaudière en marche, vérifiez le dispositif de sûreté d’arrêt automatique. Une fois que la chaudière est branchée à la tuyauterie de gaz et une fois que toutes les conditions de la Section 2 ont été remplies, suivez cette démarche :

1. Avant de commencer les tests, assurez-vous que

la valve manuelle principale de gaz et toutes les

autres valves de démarrage de la chaudière sont

en position OFF (arrêt).

NOTA: La valve de gaz est arrêtée comme suit :

2. Appuyez légèrement sur le bouton de contrôle de

gaz et tournez-le dans le sens des aiguilles d’une

montre à OFF. Le bouton ne peut pas tourner à

moins d’appuyer légèrement. Ne pas forcer.

3. Assurez-vous que l’interrupteur sur la chaudière

est en position ON (marche). Réglez tous les

dispositifs de sécurité (limite haute, interrupteur

de pression, arrêt-eau-minimum, etc.).

Page 18

LAARS Heating Systems

4. Séquence normale d’opération. Quand la pompe de circulation est en marche, la chaudière se mettra automatiquement en marche ou s’arrêtera en fonction de la température de l’eau. Quand l’eau refroidit au-dessous de la température réglée, il se produira la séquence suivante : a. L’aquastat met en marche la commande

d’allumage.

b. La commande d’allumage met en marche le

ventilateur de combustion. Après une purge de pré-allumage d’environ15 secondes, tandis que le ventilateur dégage la chambre de combustion, l’allumeur se met en marche. L’allumeur met environ 25 secondes pour chauffer. Vous pouvez voir une lueur par le hublot d’inspection (voir Figure 13).

Air

Gas

Orifice

Equalizer

Tube

Negative

OUT OF

Pressure Regulator

Gas

PRODUCTION

Air/Gas

Mixture

Figure 13. Typical Venturi System.

NOTA: La valve manuelle de gaz doit être en

position ON pour que le brûleur s’allume. Cette valve se met en marche comme suit :

c. Tournez sur ON dans le sens contraire des

aiguilles d’une montre.

d. Quand l’allumeur est chaud, le contrôle

d’allumage tourne la valve de gaz et le brûleur s’allume. Vous pouvez voir la flamme du brûleur par le hublot d’inspection (voir Figure 13).

e. La chaudière fonctionne jusqu’à ce que

l’aquastat détermine que l’eau est assez chaude et le brûleur s’arrête. Le ventilateur de combustion continue pendant encore environ une minute pour évacuer tous les produits de combustion de la chaudière.

Si l’allumeur n’arrive pas à allumer le brûleur dans la troisième étape (par exemple, s’il y a de l’air dans le tuyau de gaz), la commande d’allumage ferme la valve de gaz après quelques secondes de fonctionnement. La séquence de purge et d’allumage est répétée automatiquement. S’il n’y a pas d’allumage après trois essais, la commande d’allumage « se bloque » jusqu’à ce que le problème soit corrigé. Appelez un technicien de service qualifié.

3.2 Hi-Limit Checkout

After running the boiler for a long enough period to bring the water temperature within the range of the hi-limit, slowly back off the high limit setting until the boiler shuts off. The main burners should re-ignite when the hi-limit is turned back up to its original setting and the hi-limit is reset.

3.3 Venturi and Gas Pressure Regulator

System

3.3.1 Overall Operation

The gas control system of the Mighty Max heater is similar to that of a carburetor of a gasoline engine (see Figure 13): a venturi pulls the gas into the combustion air stream. In this system, changes in combustion air flow automatically change the gas flow.

The flow of air through the venturi creates a pressure difference. At the narrowest point of the venturi, the throat, high velocity creates a low pressure condition which pulls gas in through an orifice.

For a correct gas/air ratio, the gas pressure must be the same as the air pressure, but with a slight negative offset. A special gas regulator (called a “negative pressure regulator”) which has an equalizer tube connected to the venturi inlet, maintains the required gas pressure.

When the system is operating, a combustion fan forces air into the venturi, creating pressure at the inlet. The gas regulator sets gas pressure, and gas is pulled through the orifice. The sizes of the venturi throat and gas orifice are factory set to provide the correct air/gas ratio.

3.4 To Start Up System

(See Section 3.1 for Startup Requirements)

1. Be certain the system pump is running.

2. Set the thermostat or aquastat to its lowest

setting.

3. Turn off electric power to the appliance.

4. Remove the control access panel.

5. Turn off the manual gas valve.

Page 19

Mighty Max Volume Water Heater

Page 19

6. Wait five (5) minutes to clear out any gas, then smell for gas, including near the floor. Be sure to smell next to the floor because some gas is heavier than air and will settle on the floor.

CAUTION

This appliance is equipped with an ignition device which automatically lights the burner. Do not try to light the burner by hand.

ATTENTION

Cet appareil est équipé avec un dispositif d’allumage qui allume automatiquement le brûleur. N’essayez pas d’allumer le brûleur manuellement.

WHAT TO DO IF YOU SMELL GAS

· Do not try to light any appliance.

· Do not touch any electric switch; do not use any phone in your building.

· Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.

If you don’t smell gas, go to the next step.

7. Turn on manual gas valves.

8. Reset all safety devices (manual resets on high limit, low water cutoff, etc.).

9. Replace control access panel.

10. Turn on all electric power to the boiler.

11. Set thermostat to desired setting.

12. If the boiler will not operate, follow the instructions to turn off gas to heater and call your

PRODUCTION

service technician or gas supplier.

a. Turn off main electrical switch. b. Close all manual gas valves.

3.4.1 Setting Temperature Controls

To set the temperature and high-limit controls:

a. Set the temperature controller at the system

design temperature.

b. For heaters with the temperature controller bulb

at the heater inlet, set the high-limit 40ºF to 50ºF above temperature controller setting.

c. For heaters with the temperature controller bulb

at the heater outlet, set the high-limit 15ºF to 25ºF above temperature controller setting.

3.5 To Shut Down System

To shut down the boiler, turn off all manual

gas valves and electrical disconnect switch.

NOTE: There is a filter which needs to be cleaned prior to setting pressures. See section labeled “Filter Service” before proceeding

3.6 Venturi Adjustment - Natural Gas

Verifying proper operation of the combustion

OUT OF

flow system has two aspects - air flow and gas flow. Air flow is checked by measuring pressures at service taps on the venturi. Gas flow is checked by evaluating venturi pressures and the regulator offset pressure.

In a venturi flow system the difference between various pressures is far more important than their “gauge” value relative to the room. The gas pressure offset and the gas orifice pressure differential are especially important concepts. The following section describes this setup procedure.

3.6.1 Pressure Measurement Ports Natural Gas

Air flow enters the venturi through the filter box and blower assembly. It is pushed through a converging section and into the throat, where pressure is reduced substantially. Gas flow is pulled into the throat through an orifice. The orifice is located between the throat and the regulator. Air and gas are combined in the throat and mix thoroughly as they proceed through the venturi tailpipe to the burner.

Service taps are provided at three places. One is located on the chamber with the gas connection, this tap is called the gas plenum tap. The other is located above the gas plenum tap, this port is called the venturi inlet tap. The third tap, gas orifice tap, is located on the red orifice holder directly before the gas connects to the venturi. These taps have service plugs in them. Do not remove any of the plastic fittings or plastic tubing. To evaluate system operation requires accurate measurement at these taps. An inclined manometer with a zero to 6 inches water column range is ideal. Other instruments may be used, but the “positive/negative” nature of the readings must be well understood. Gas pressure offset measurements are at very low levels (0.4" WC), the instrumentation must be capable of determining it accurately (see Figures 14, 15 and 16).

3.6.2 Adjustment Procedure - Natural Gas

Note that an equalizer tube is connected from a port on the side of the venturi inlet to the port of the regulator. This is a very important component which allows the regulator to track air pressure even when abnormal conditions occur, such as blockage of the combustion air. Before firing, confirm that this tube and the venturi pressure switch tubes are in place and firmly connected.

The field checkout involves measuring gas and venturi pressures, and observing the flame through the sight glass. If necessary, the gas input rate can be measured by timing the gas meter.

Install shutoff valves at the gas orifice (regulator outlet) tap (red), at the venturi inlet tap and at the gas plenum tap. Do not remove any of the plastic fittings or plastic tubing. After installing the shutoff valves, be certain they are closed.

Page 20

LAARS Heating Systems

Venturi

Inlet Tap

5.8" WC

Gas

Orifice Tap

Gas

Plenum Tap

OUT OF

Figure 14. Unfired Venturi Differential Pressure Natural Gas.

PRODUCTION

4.0" WC

Figure 16. Gas Orifice Differential Pressure - Natural Gas.

a. Unfired Venturi Differential Pressure

NOTE: Turn off the main manual gas valve.

The difference in pressure between the venturi inlet tap and the gas plenum tap (see Figure 14). This measurement is taken by connecting the positive side of the manometer to the venturi inlet tap and connecting the negative side of the manometer to the gas plenum tap. This measurement is taken with the boiler not firing. It is a temporary setting used to start the boiler and check for air flow problems.

0.4" WC

Figure 15. Gas Offset Pressure - Natural Gas.

b. Gas Offset Pressure - Natural Gas

The difference in pressure between the venturi inlet tap and the outlet of the gas regulator (see Figure 15). This measurement is taken by connecting the positive side of the manometer to the venturi inlet tap and connecting the negative side of the manometer to the gas orifice tap. This measurement is an indication of the gas to air ratio and must be performed while the unit is firing.

c. Gas Orifice Differential Pressure -

Natural Gas

This measurement is the pressure drop across the gas orifice. This measurement is taken by connecting the positive side of the manometer to the gas orifice tap and the negative side of the manometer to the gas plenum tap (see Figure 16). This measurement in conjunction with the gas orifice size is an indication of the gas firing rate and must be performed while the unit is firing.

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Mighty Max Volume Water Heater

Page 21

By setting the gas offset pressure and gas orifice differential pressure according to Table 10, the correct input rate and gas to air ratio is achieved.

3.6.3 Venturi Setup Procedure Natural Gas

1. Loosen the nut on the blower shutter to allow for adjustment. Turn the heater on so that the blower is running and the heater is not firing. Measure the unfired venturi differential pressure. In this unfired condition, adjust the shutter until the unfired venturi differential pressure is according to Table 10, “Unfired Venturi Differential” (5.8 ± .3 inches wc at sea level). If this pressure range can not be achieved, check for blockage in the combustion air inlet, boiler and venting system. If there is no obvious cause contact a qualified Laars service technician.

2. Approximately 40 seconds after the blower starts the gas valves will open. The heater is now firing. If the heater is not running, check all manual gas valves and heater safety devices. Ensure proper gas supply pressures according to Table 4 in Section 2.

ELEVATION, OFFSET DIFFERENTIAL VENTURI

FT PRESSURE PRESSURE DIFFERENTIAL

SEA LEVEL +0.4 +4.0 +5.8

2000 +0.4 +3.7 +5.3

PRODUCTION

4000 +0.4 +3.4 +4.9 6000 +0.4 +3.2 +4.6 8000 +0.4 +2.9 +4.2

10000 +0.4 +2.7 +3.9

Table 10. Venturi Pressure Settings - Natural Gas.

3. Measure the gas offset pressure. Using the regulator only, adjust the gas offset pressure according to the installation’s altitude in Table 10 (+0.4 inches wc. at sea level). REPLACE THE REGULATOR CAP BEFORE TAKING GAS PRESSURE READINGS. Turn the regulator screw clockwise to decrease the gas offset pressure, turn the regulator screw counterclockwise to increase the offset.

4. Using the toggle switch, turn the heater off. Turn the heater back on and check the gas offset pressure while the heater is firing. If the gas offset pressure is not according to Table 10, adjust the regulator as needed.

5. Measure the gas orifice differential pressure. This pressure must be adjusted according to Table 10 (4.0 ± .2 inches wc at sea level). Use the blower shutter to adjust the gas orifice differential.

GAS GAS ORIFICE UNFIRED

inch W.C. inch W.C. inch W.C.

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Venturi Inlet

“Low” Side of

Manometer

“High” Side of

Manometer

Venturi Throat

Tap (Yellow)

Figure 17. Measurement of Venturi Throat Pressure Differential - Propane Gas.

6. By adjusting the gas orifice differential, the gas offset pressure will change. Therefore you must repeat steps 3-5 until the gas offset and gas orifice differential pressures are according to Table 10.

7. After setting all pressures, turn the heater off and replace each shutoff valve with the factory installed threaded plugs. The venturi has now been adjusted for proper operation.

Tap (Blue)

Gas Orifice

Tap (Red)

3.7 Venturi Adjustment - Propane Gas

The field checkout involves measuring gas and

venturi pressures, and observing the flame through the sight glass. If necessary, the gas input rate can be measured by timing the gas meter.

Use a single, inclined manometer or digital

manometer with a 4.0 inch water column range. Install shutoff valves at the gas orifice (regulator outlet) tap (red), at the venturi inlet tap (blue) and at the venturi throat tap (yellow). After installing the shutoff valves, be certain they are closed (see Figure 17).

1. With the heater off, connect the positive side of the manometer to the shutoff valve on the venturi inlet tap (blue). Open the shutoff valve.

2. Loosen the nut on the blower damper to allow for adjustment. Turn the boiler on so that the blower is running and the heater is not firing. In this unfired condition, adjust the damper until the venturi inlet pressure (blue tap) is 1.2 inches water column.

3. Approximately 40 seconds after the blower starts the gas valves will open. The heater is now firing. If the heater is not running, check all manual gas valves and heater safety devices. Ensure proper gas supply pressures according to the table in Section 2.

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LAARS Heating Systems

4. Now that the heater is firing, use the blower damper to readjust the venturi inlet pressure according to the installation’s altitude in Table 11 (+1.6"w.c. at sea level).

Elevation Venturi Inlet Gas Throat

Ft. Pressure Pressure Differential

SEA LEVEL +1.6 +0.4 +2.6

1000 +1.5 +0.4 +2.5

2000 +1.5 +0.4 +2.4

3000 +1.4 +0.4 +2.3

4000 +1.4 +0.3 +2.2

5000 +1.3 +0.3 +2.2

6000 +1.3 +0.3 +2.1

7000 +1.2 +0.3 +2.0

8000 +1.2 +0.3 +1.9

9000 +1.1 +0.3 +1.9

10000 +1.1 +0.3 +1.8

Table 11. Venturi Pressure Settings - Propane Gas.

5. Leaving the positive side of the manometer connected to the venturi inlet tap (blue), connect the negative side of the manometer to the shutoff valve on the gas orifice tap (red). Open the shutoff valve to take a pressure reading. This reading is called the gas pressure offset. Using the regulator only, adjust the gas pressure offset according to the installation's altitude in Table 11 (+0.4" w.c. at sea level). REPLACE THE REGULATOR CAP BEFORE TAKING GAS PRESSURE READINGS. Turn the regulator screw clockwise to decrease the gas pressure offset, turn the regulator screw counterclockwise to increase the offset.

6. Using the toggle switch, turn the heater off. Turn the heater back on and check the gas pressure offset after the heater has fired. If the gas offset pressure is not according to Table 11, adjust the regulator as needed.

7. While the heater is still running, close the shutoff valve on the gas orifice tap (red), then remove the manometer hose from the shutoff valve. Connect the negative side of the manometer to the shutoff valve on the venturi throat tap (yellow). This reading is called the venturi throat differential pressure and should appear according to altitude in Table 10 (+2.6" w.c. at sea level). If it does not appear according to Table 11, contact a qualified service technician. After setting all pressures, turn the heater off and

replace each shutoff valve with the factory installed threaded plugs. The venturi has now been adjusted for proper operation.

(Blue Tap) Offset Pressure

“WC H

0” “WC H20” “WC H20”

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SECTION 4. Maintenance

4.1 General Instructions

1. Oil the water circulating pump in accordance with the manufacturer's instructions.

2. Oil the blower motor bearings every 6 months.

3. If a strainer is used in a pressure reducing valve or in the piping, clean it every 6 months in accordance with the manufacturer's instructions.

4. At startup and every 6 months after, look at the main burner flame for proper performance. The burner should not require maintenance in normal operation. If any malfunction indicates that the burner needs service (e.g., a flame that is yellow, or entire burner surface glowing red), call a professional service technician. Flame characteristics may be inspected during the first 30 seconds after ignition. Characteristics of a good flame are:

a. Blue flame color b. Dark-colored burner surface with

occasional glowing fibers on surface.

NOTE: After 30 seconds of operation the combustion chamber will heat up and prevent reliable flame observation.

5. Inspect the venting system for blockage, leakage, and corrosion at least once a year.

6. Keep the heater area clear of combustible material, gasoline, and other flammable liquids and vapors.

7. Be sure all combustion air and ventilation openings are not blocked.

8. After installation and first startup, check the heat exchanger for black carbon soot buildup after the following periods of operation: 24 hours, 7 days, 30 days, 90 days, and once every 6 months thereafter.

4.2 Heat Exchanger

Black carbon soot buildup on the external

surfaces of the heat exchanger is caused by one or more of the following: incomplete combustion, combustion air problems, venting problems and heater short cycling. As soon as any buildup is seen, correct the cause of the buildup. Scale can build up on the

inner surface of the heat exchanger tubes and restrict the water flow. Inspect the heat exchanger in

accordance with Section 4.2.1.

If the heat exchanger needs cleaning see

Section 4.2.2.

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Mighty Max Volume Water Heater

4.2.1 Inspection of the Heat Exchanger

WARNING

Improper installation or maintenance can cause nausea or asphyxiation from carbon monoxide in flue gases which could result in severe injury, property damage, or death.

AVERTISSEMENT

Une installation ou un entretien inadéquat peut causer des nausées ou l’asphyxie provenant du monoxyde de carbone présent dans les gaz de combustion et provoquer des dégâts matériels, des blessures graves, voire la mort.

4.2.1a External Heat Exchanger Inspection

1. Disconnect electrical supply to the heater.

2. Turn off the gas supply by closing the manual

gas valve on the heater.

3. On indoor models, remove the vent pipe, top jacket section, flue collector.

4. On outdoor models, remove outdoor vent terminal, top jacket section, flue collector.

5. After removing the flue collector, inspect the finned copper tubing using a flashlight.

6. If there is a buildup of black carbon soot or other

7. If there is no buildup of black carbon soot or

1. Remove the inlet/outlet header of the heat

2. Remove the return cover of the heat exchanger.

3. Inspect the internal surface of the copper tubes

4. If buildup exists clean per 4.2.2b.

NOTE: The heat exchangers are heavy and may require two people to remove to avoid personal injury.

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debris on the heat exchanger tubes which may restrict flue gas passage, refer to section 4.2.2a.

other debris which may restrict flue gas passage through the heat exchanger, reassemble the heater.

4.2.1b Internal Heat Exchanger

Inspection

exchanger.

for signs of scale buildup and erosion.

4.2.1c. Cleaning the Heat Exchanger -

External

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ARROW

FILTER

Figure 18. Filter Exposed for Cleaning.

WARNING

Black carbon soot buildup on a dirty heat exchanger can be ignited by a random spark or flame. To prevent this from happening, dampen the soot deposits with a wet brush or fine water spray before servicing the heat exchanger.

AVERTISSEMENT

L’accumulation de suie noire sur un échangeur de chaleur sale peut être enflammée par une étincelle ou une flamme. Pour éviter ce genre d’accident, humectez les dépôts de suie avec une brosse mouillée ou une aspersion légère d’eau avant de travailler sur l’échangeur de chaleur.

1. Disconnect the 120 Vac electrical supply to the

heater.

2. Turn off the gas supply by closing the manual

gas valve on the heater.

3. Disconnect and remove the wires and conduit from the low water cutoff.

4. Remove the top jacket section, venting and the flue collector as mentioned in Section 4.2.1 “Inspection of the Heat Exchanger”.

5. Isolate the heat exchanger from water supply.

6. Drain the heat exchanger.

7. Disconnect the flange and adapter tee from the heat exchanger inlet and outlet.

8. Remove temperature sensing probes from the inlet/outlet header.

9. Remove the heat exchanger from the heater.

10. Remove the heat baffles from the heat exchanger.

11. Clean the heat exchanger: A light accumulation of soot or corrosion on the outside of the heat exchanger can be easily removed after the heat baffles are removed. Use a wire brush to remove loose soot and scale from the heat exchanger. Do not use water or compressed air for cleaning.

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LAARS Heating Systems

NOTE: While the heat exchanger is out of the heater, inspect the firewall refractory insulation blocks for cracks, wear and breakage. Replace if necessary.

4.2.1d Cleaning the Heat Exchanger Internal

1. Remove the inlet/outlet header of the heat exchanger.

2. Remove the return cover of the heat exchanger.

3. Clean the internal surface. (Laars offers a tube cleaning kit part number R0010000.)

4. Reassemble in the reverse order.

4.3 Gas and Electric Controls

The gas and electric controls on the heaters are

designed for both dependable operation and long life. Safe operation of the heater depends on their proper functioning. A professional service technician should check the following basic items every year, and replace when necessary.

NOTE: The warranty does not cover damage caused by lack of required maintenance or improper operating practices.

1. Water temperature controls.

2. Ignition control system.

3. Automatic electric gas valve(s).

4. Flow sensing safety device.

5. Low water cutoffs, including flushing or float types. (Every six months).

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Other maintenance requirements include:

1. Periodic cleaning of filters, when supplied.

2. Lubrication of moving parts (when applicable), with the correct type and amount of lubricant.

3. Periodic examination of the venting system.

4. Periodic cleaning of vent terminal screens, where applicable.

5. Cleaning flue gas passageways.

4.4 Filter

4.4.1 Filter Function

A filter has been designed into the operation of

this Mighty Max boiler. Its function is to filter the combustion air before it is delivered to the burner system. The filter is manufactured out of a polyurethane foam and may be cleaned with a mild soap and water solution. Clean the filter only after the filter has been removed from the filter housing (see Figure 18).

4.4.2 Filter Service

(The filter does not need cleaning if this is a first

time heater start-up).

1. Turn the heater off using the toggle switch.

2. Remove the door panel and bonnet from the jacket.

3. Remove the screws on the filter housing to expose the filter as shown in Figure 18.

4. Inspect the filter for discoloration due to contamination or any other forms of debris. If contamination or debris exists, wash the filter in a soap/water solution then rinse with water only. It is important that the placing it back in the filter housing.

The filter has arrows which indicate the direction of the air flow. Failure to install the filter correctly may cause blower failure and dangerous operation.

Le filtre a des flèches qui indiquent la direction de l’air. Si le filtre n’est pas installé correctement, le souffleur peut ne pas fonctionner, ce qui serait dangereux.

The filter must be inspected for contamination

one week after start-up. Depending upon the severity of contamination, a suitable cleaning schedule may be developed. The factory recommends cleaning the filter at least once every 30 days. In high contamination areas, such as construction sites, factories, etc., the filter may need to be cleaned daily. Failure to do so could result in lower heat output and potential unsafe operation.

filter be dry before

CAUTION

ATTENTION

SECTION 5. Troubleshooting

5.1 Sequence of Operation

To troubleshoot the heater properly you must

first understand the sequence of operation of the heater:

1. Upon a call for heat a 24 Vac signal is sent through fusible links and high limit(s) to the ignition control “TH” terminal.

2. The “IND” terminal of the ignition control is energized for a 15 second pre-ignition purge period during which the combustion blower purges the combustion chamber.

3. After the purge period there is a 20 to 35 second igniter heat up period. The glow of the igniter can be seen through the heater sight glass.

4. Then there is a seven second trial for ignition. During this time the gas valves are energized and the main burner ignites. The gas valves will remain energized throughout the call for heat as

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Mighty Max Volume Water Heater

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Figure 19. Troubleshooting Chart.

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Figure 20. Lower Front Panel Removal.

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long as the ignition control igniter senses a stable flame.

5. After the call for heat is satisfied the ignition control closes the gas valves and operate the blower for a thirty (30) second post purge cycle. This clears the combustion chamber of combustion products.

The ignition is attempted three times. If ignition

is not successful, the control shuts down and “locks out”. It remains in the lockout condition until the heater is turned off then back on or 120 Vac power to the heater is interrupted.

5.2 Venturi and Gas Pressure Regulator System

Field Checkout

See Section 3.2 “Venturi and Gas Pressure

Regulator System” for proper setup procedure.

5.3 Electrical Components

This section describes guidelines for checking

the operation of electrical components installed on the heater. Refer to the wiring diagram for correct connection locations.

5.3.1 General Troubleshooting

This section describes guidelines for checking

the electrical components of the heater. Experience has shown that most complaints about heaters failing to fire have nothing to do with the heater itself. Usually, one of the protective switches in the heater system has shut down operation.

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LAARS Heating Systems

Any of the following can prevent proper

operation. Check these items first:

1. Be sure the heater has been properly installed (see Section 2).

2. Make sure the pump is not airlocked, clogged or otherwise inoperative.

3. Make sure the gas valve is on and there is sufficient gas pressure in the line. All external gas valves must be open.

WARNING

The ignition control and igniter operate on 120V power. Keep this in mind while servicing the heater, and take care to avoid contact with electrically live/ energized parts which will cause electrocution, leading to property damage, injury or loss of life.

ATTENTION

Débranchez la chaudière avant d’enlever ou de remplacer tout élément ou branchement de fil. Si la chaudière est branchée, « connecter » la valve de gaz ou mettre accidentellement à la terre le faisceau de fils ou des terminaux au corps ou à la gaine de la chaudière peut faire sauter le plomb (ou disjoncteur) de la commande d’allumage.

4. Verify that the electrical circuit serving the boiler is ON

5. Make sure the toggle switch on the right side of the boiler is ON.

6. Check the fuse inside the black, twist-lock fuse holder. If it is burned, replace it with a 2-amp fuse (part number E0084400).

7. With the power off inspect all electrical connections and wiring. Finding a loose connection or charred wire can save a lot of time and money.

8. Make sure the temperature controller is set high enough to call for heat.

9. Make sure none of the manual reset controls, i.e., low water cutoff, high limit, etc., have tripped. Reset any tripped switches

If the pump is circulating water and the

foregoing items check out okay, the trouble may be in the boiler control system.

Caution: Disconnect power to the heater before

removing or replacing any component or wire connection. If the power is not disconnected, “jumping” the gas valve or accidentally grounding the wire harness or component terminals to the heater frame or jacket could cause the ignition control fuse to blow.

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Mighty Max Volume Water Heater

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5.3.2 Electrical Troubleshooting

Troubleshooting procedures should only be performed by professional service technicians qualified in heater maintenance.

Some electrical components are wired in parallel, so it is necessary to troubleshoot in the order that they appear on the wiring diagram or the troubleshooting flow chart (see Figure 19).

The following steps should be used when troubleshooting the heater:

1. Remove the lower front panel (see Figure 20).

2. Turn the manual gas valve on the heater off.

3. If the heater has locked out turn the toggle switch

off for 5 seconds then back on to reset the heater.

4. Use the troubleshooting flow chart (Figure 19) to

determine what components and wiring should

be tested first.

5. Test each component by checking for 24 Vac or

120 Vac entering and exiting the device. If there

is voltage entering the safety device, but none

leaving then there is an open circuit and it must

be determined why it is open. When testing

components between “MV1” of the ignition

control and the gas valve install a meter and let

the heater cycle through one complete sequence

of operation. During the sequence of operation

these safeties will only be energized for the

seven second trial for ignition.

6. Turn the manual gas valve on the heater on and

Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. Verify proper operation after servicing.

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fire the heater.

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CAUTION

ATTENTION

SECTION 6. Parts List for Mighty Max VW Heater

6.1 General Information

To order or purchase parts for the Laars Mighty Max VW heater, contact your nearest Laars contractor or distributor. If they cannot supply you with what you need, contact:

Customer Service Department

Laars Heating Systems

6000 Condor Drive

Moorpark, California, 93021

Telephone (805) 529-2000

In Canada, contact:

Customer Service Department

Laars Heating Systems

480 S. Service Road West

Oakville, Ontario, Canada L6K 2H4

Telephone (905) 844-8233

Item Description Part Number

1. Base Assembly

320M ........................................................... 20157801

400M ........................................................... 20157802

2. Burner and Burner Plenum Weldment

320M ........................................................... 20268401

400M ........................................................... 20268402

3. Venturi Assembly

320M ........................................................... 20158601

400M ........................................................... 20158602

4. Combustion Chamber Weldment

320M ........................................................... 20159101

400M ........................................................... 20159102

5. Gas Train Assembly

320M ........................................................... 20254901

400M ........................................................... 20254902

Gas Valve

320M, 400M ................................................ V2003900

Orifice Holder

320M, 400M ................................................ P2017500

6. Motor, Blower

320M thru 520M Nat. & Prop. Gas ............. A2088100

7. Electrical Controls

High limit Control ........................................... E0015900

Toggle Switch ................................................. E0109200

Indicator Light ................................................ E0071300

Fusible Link ................................................... E0099403

Transformer ................................................... E0086100

Fuse Holder ................................................... E2000300

Fuse, 2 Amp .................................................. E2043600

Flow Switch .................................................... E0013000

Burner Temperature Switch ........................... E2076100

Low Water Cutoff ........................................... E2075100

Pump Time Delay .......................................... E2077700

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LAARS Heating Systems

Item Description Part Number

8. Sight Glass .................................................... F0044800

9. Igniter, Hot Surface ....................................... W0038001

10. Gasket, Igniter Hot Surface ........................... 20409800

11. Control, Remote Ignition ................................ E2101300

12. Control, Temperature ..................................... E2101400

13. Display, Temperature ..................................... E2101600

15. Heat Exchanger Assy., 4 pass, Copper Tubes

320M ........................................................... 20259601

400M ........................................................... 20259602

Heat Exchanger Assy., 4 pass, Cupronickel tubes

320M ........................................................... 20104701

400M ........................................................... 20104702

16. Cover, Machined In/Out ................................. 20150200

17. Plate, Mach. Adapter

320M, 400M ................................................ 20150302

18. Flange, Machined

320M, 400M ................................................ 20255400

19. Cover, Machined Rear ................................... 20150100

20. Pressure Switch, Differential 320-400 ........... E0115200

21. Flue Collector Assembly (with gaskets)

320M ........................................................... 20155401

400M ........................................................... 20155402

22. Jacket Assembly (not shown)

320M ........................................................... 20255201

400M ........................................................... 20255202

23. Covering Plate (side) ..................................... 20256500

24. Collar, Jacket 320-400 ................................... 20258300

25. Bonnet

320M ........................................................... 20156801

400M ........................................................... 20156802

26. Panel Top

320M ........................................................... 20157501

400M ........................................................... 20157502

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Item Description Part Number

27. Panel, Top Side, Left ...................................... 20152800

28. Panel, Side, Left ............................................ 20152700

29. Panel, Bottom Side, Left ................................ 20152900

30. Panel, Access

320M ........................................................... 20157401

400M ........................................................... 20157402

31. Panel, Back

320M ........................................................... 20157201

400M ........................................................... 20157202

32. Plate, Blank (back)

320M ........................................................... 20256201

400M ........................................................... 20256202

33. Panel, Side, Right .......................................... 20157100

34. Panel, Top Side, Right ................................... 20157000

35. Panel, Bottom Side, Right ............................. 20156900

36. Blocked Vent Safety Switch ........................... E2103000

37. Cover Plate For Gas Conn.

320M, 400M ................................................ 20262701

38. Tile Assembly

320M ........................................................... 20255101

400M ........................................................... 20255102

39. Outdoor Terminal Kit

320M ........................................................... 20254701

400M ........................................................... 20254702

40. Side Wall Vent Terminal (when used) (not shown)

320M ........................................................... D2004500

400M ........................................................... D2004600

41. Sidewall Comb. Air Terminal (when used) (not shown)

320M ........................................................... 20260701

400M ........................................................... 20260702

Filter ............................................................ A2088700

Filter Gasket ............................................... S2006100

Filter Housing Gasket, Top ......................... S2006200

Filter Housing Gasket, Side ........................ S2006300

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Mighty Max Volume Water Heater

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Front View

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Right Side View

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LAARS Heating Systems

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Front ViewRear View

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Right Side ViewLeft Side View

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Mighty Max Volume Water Heater

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A subsidiary of BRADFORD WHITE Corporation

20 Industrial Way, Rochester, NH 03867 • 603.335.6300 • Fax 603.335.3355 1355 Kuehner Drive, Simi Valley, CA 93063 • 800.900.9276 • Fax 800.559.1583 480 S. Service Rd. West, Oakville, Ontario, Canada L6K 2H4 • 905.844.8233 • Fax 905.844.2635

(Sales, Service)

H0192500D

LAARS Mighty Max VW User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual