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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.

WARNING

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.

Installation and Operation
Instructions for

Mighty Therm

Volume Water Heaters
Models VW, PW and IW
Sizes 500-1825

These instructions are to be stored in the pocket provided on the boiler.

H0105000D

Installation and Operation Instructions

Document  2040D

Summary of Contents for IW

Page 1: ... 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 ...

Page 2: ...er Piping of System 8 2G Water Expansion 9 2H Pump Performance and Installation 10 2I Water Pressure 16 2J Tank Installation 16 2K Two Temperature System 16 SECTION 3 Operation 3A Controls General 16 3B Initial Start Up 17 TABLE OF CONTENTS 3C To Start Up System 18 3D ToTurnOffHeater 19 3E To Shut Down System 19 SECTION 4 Maintenance 19 SECTION 5 Troubleshooting and Analysis of Service Problems 20...

Page 3: ...uirement When required by the authority having jurisdiction the installation must conform to American Society of Mechanical Engineers safety codes for controls and safety devices for automatically fired heaters No CSD 1 and in Canada CGA 3 3 Any modification to the water heater its gas controls gas orifices wiring or draft diverter may void the Laars warranty If field conditions require such modif...

Page 4: ...he internal copper surfaces will be extremely shiny Other chemicals such as chlorine or chlorides in the water will cause dark surfaces of erosion In areas where the water supply is extremely corrosive it is advisable to order the heater with cupro nickel tubes in the exchanger Damage From Scaling Corrosion or Erosion is Not Covered by the Warranty SECTION 2 Installation 2A Heater Placement The he...

Page 5: ...567890 12345678901234567890 12345678901234567890 12345678901234567890 12345678901234567890 12345678901234567890 12345678901234567890 12345678901234567890 12345678901234567890 12345678901234567890 CLOSET INSTALLATION UNACCEPTABLE A closet is any 4 sided enclosure which is less than 16 times the total volume of all the gas fired appliances within the enclosure ROOM INSTALLATION ACCEPTABLE A room is ...

Page 6: ... should make sure it does not create drafts which could cause nuisance shutdowns of the pilot If a blower is necessary to provide adequate combustion air to the heater a suitable switch or equivalent must be wired into the heater control circuit to prevent the heater from firing unless the blower is operating 5 The heater must be completely isolated and protected from any source of corrosive chemi...

Page 7: ...in Table 1 Placement of Heater 2 Do not place the heater in an enclosure or wall recess Avoid locations where wind deflection off structures might cause down draft When such wind conditions are possible place the heater at least three 3 feet from the structures 3 Never install the heater under any kind of roof overhang Do not place the heater below or adjacent to any doors windows louvers grills e...

Page 8: ...esting unless it has been determined that the leak test solution is noncorrosive 2E Electrical Wiring WARNING The heater must be electrically grounded in accordance with the most recent edition of the National Electrical Code ANSI NPA 70 In Canada all electrical wiring to the heater should be in accordance with the Canadian Electrical Code CSA C22 1 Part 1 Do not rely on the gas or water piping to...

Page 9: ...ve hot water from entering mixed water supply Bring the cold water supply up from the floor to the valve see Figure 10 2G Water Expansion When cold water is heated the water expands If no water is being used during the heat up period the expanded water will normally back up into the city mains A water pressure reducing valve installed in the incoming cold water line may act as a check valve and pr...

Page 10: ...1 4 x 100 ft 1010 through 1220 10 2 1 1 2 x 100 ft 1430 through 1670 17 0 2 x 100 ft 1825 27 0 2 1 2 x 100 ft The gallons shown are the calculated volumes of the pipes 4 Model VW PW and IW heaters are not suitable for heating swimming pools or any other application where temperature of the water flowing through the heater remains below the dew point 110 F In applications requiring the rapid use of...

Page 11: ...Mighty Therm Volume Water Heater Page 11 Figure 11 Hot Water Supply System Model VW PW With Vertical Tank With Horizontal Tank NOTES Heavy line indicates Heater to Tank Circulating Loop ...

Page 12: ...2 Pipe size and length must conform to the recommendations for each heater model 3 A loop circulator is required to maintain forced circulation in the building hot water piping system Figure 13 Split System Piping Diagram Model IW Figure 12 Hot Water Supply System Using Model PW with Dual Tanks Building Loop Return and Circulating Pump ...

Page 13: ...ll water connections 2 N P T models 2 Drain valve per ASME requirements 3 A loop circulator is required to maintain forced circulation in the building hot water piping system NOTES 1 All water connections 2 N P T models 2 Drain valve per ASME requirements 3 A loop circulator is required to maintain forced circulation in the building hot water piping system ...

Page 14: ...alves in Building Loop Returns I Circulating Pump for 180 Building Loop J Circulating Pump for 140 Building Loop K Service Valves to Isolate Heater and Pump for Service Legend B Check Valve in Hot Water Supply to Tempering Valve C Check Valve in Return Line from Building Loop D Tempering Valve E Venturi Suction Tee H Throttling Valves in Building Loop Returns I Circulating Pump for 180 Building Lo...

Page 15: ... Hot Water Supply System with Vertical Tank for Models VW and PW Water Heaters Legend B Check Valve C Check Valve D Tempering Valve H Throttling Valves in Building Loop Returns J Circulating Pump for Return Loop K Service Valves to Isolate Heater and Pump for Service ...

Page 16: ...ank drain fitting that goes to a floor sink and install a drain valve If a floor sink is not available install a hose bib 7 Hot water tanks in an existing installation are likely to have a deposit of silt on the bottom Therefore it is important to extend the pump suction pipe in the tank to a position near the top Pipe the return from the heater to the bottom of the tank 2K Two Temperature System ...

Page 17: ... High Limit Controls The manual reset high limit switches are provided as standard equipment on all heaters Automatic reset switches are optionally provided The temperature sensing bulb of the switch is always located in the heater outlet Burners will automatically shut down whenever overheating of water occurs 4 Flow Switch Standard on all models Models VW and PW the switch is mounted in the outl...

Page 18: ...g the manual pilot valve in the closed position and at the same time begin recording the time it takes for the output signal from the electronic ignition control to be interrupted The signal interruption can be detected either with a test light or a voltmeter The response time should never exceed one second 4 With the pilots lit initial activation of the main burners can be achieved by slowly open...

Page 19: ...lean it every six 6 months 3 At start up and every six 6 months thereafter the pilot and main burner flame should be observed for proper performance see Figure 21 See attached lighting and shut down instructions for proper pilot flame pattern If flame has the appearance of sooting tips check for debris near orifices Call serviceman 4 Inspect the venting system for obstruction leakage and corrosion...

Page 20: ...lowing tools are required a Gas pressure test kit with range from zero to 14 W C Either a slack tub manometer or an accurate gas pressure gauge is acceptable with proper adapters which will connect to the available fittings in the line and on the gas valve b Multi meter with the following ranges 0 to 500 volts A C 0 to 1000 ohms continuity c Tube cleaning kit consisting of reamer stainless steel b...

Page 21: ...ceeds setting of relief valve system above heater Install new valve with psi setting 25 above required static system working pressure Do not exceed 160 psi B Expansion tank is water B Drain expansion tank then logged if installed reopen it to the system Look for leaks in expansion tank or fittings Calculate required volume of expansion tank in relation to system to determine if tank is adequate V ...

Page 22: ...981 10364300 10364300 10364300 10364300 10364300 10364300 10364300 10364300 10364300 Return Header S00642 Bronze 10364301 10364301 10364301 10364301 10364301 10364301 10364301 10364301 10364301 13 Inlet Outlet Header S 00943 10364500 10364500 10364500 10364500 10364500 10364500 10364500 10364500 10364500 Inlet Outlet Header S00640 10364501 10364501 10364501 10364501 10364501 10364501 10364501 1036...

Page 23: ...perature Control Wells Inlet Outlet Header 1 Firing Mode L K C 2 Dry Wells 2 Firing Mode H A Natural Gas Boilers Heaters 500 thru 850 2 Dry Wells 1010 thru 1430 3 Dry Wells 1670 thru 1825 4 Dry Wells B Propane Gas Boilers Heaters 500 thru 850 2 Dry Wells 1010 thru 1852 3 Dry Wells ...

Page 24: ...le Rear Panel Heat Shield Weldment 10540401 10540402 10540403 10540404 10540405 10540406 10540407 10540408 10540409 33 End Panel Upper Right 10531600 10531600 10531600 10531600 10531600 10531600 10531600 10531600 10531600 34 End Panel Upper Left 10534000 10534000 10534000 10534000 10534000 10534000 10534000 10534000 10534000 35 Upper Rear Panel Heat Shield Weldment 10540501 10540502 10540503 10540...

Page 25: ...Mighty Therm Volume Water Heater Page 25 Figure 23 Tile Assemblies ...

Page 26: ...34600 W0034600 W0034600 W0034600 Pilot Burner Honeywell Standing Pilot Propane W0034400 W0034400 W0034400 W0034400 W0034400 W0034400 W0034400 W0034400 W0034400 53 Pilot Burner Johnson IID Pilot Nat W0034500 W0034500 W0034500 W0034500 W0034500 W0034500 W0034500 W0034500 W0034500 Pilot Burner Honeywell IID Pilot Nat W0034300 W0034300 W0034300 W0034300 W0034300 W0034300 W0034300 W0034300 W0034300 54 ...

Page 27: ...0011400 F0011400 F0011400 75 Plug Sq Hd 1 NPT P0033000 P0033000 P0033000 P0033000 P0033000 P0033000 P0033000 P0033000 P0033000 76 Plug 1 2 NPT P0026900 P0026900 P0026900 P0026900 P0026900 P0026900 P0026900 P0026900 P0026900 77 Nipple Brass 3 4 x 2 P0025300 P0025300 P0025300 P0025300 P0025300 P0025300 P0025300 P0025300 P0025300 78 Valve Press Relief 3 4 75 PSI A0063600 A0063600 A0063600 A0063600 A0...

Page 28: ...50703 10550704 97 Burner Tray I I D Mech Mod 3 4 Sect Manifold Nat 10551201 10551202 10551203 10551204 10551205 98 Burner Tray St Pl Mech Mod SpIt Manifold Pro 10550301 10550302 10550303 10550304 99 Burner Tray St Pl Mech Mod 3 Sect Manifold Pro 10550501 10550502 10550503 10550504 10550505 100 Combination Gas Valve V0059600 V0059600 V0059600 V0070400 V0070400 V0070400 4 Stage Nat 2 2 2 2 2 2 101 S...

Page 29: ...Mighty Therm Volume Water Heater Page 29 Figure 21 Outdoor Parts ...

Page 30: ...10658506 10658507 10658508 10658509 11 Gas Train Interface Plate 20050200 20050200 20050200 20050200 20050200 20050200 20050200 20050200 20050200 12 Front End Panel 10657500 10657500 10657500 10657500 10657500 10657500 10657500 10657500 10657500 2 2 2 2 2 2 2 2 2 13 Front Base Extension 10659701 10659702 10659703 10659704 10659705 10659706 10659707 10659708 10659709 14 Door 10660801 10660802 10660...

Page 31: ... 10667707 10667708 10667709 7 14 14 14 14 28 28 28 14 41 Middle Front Panel 10662001 10662002 10662003 10662004 10662005 10662006 10662007 10662008 10662009 42 Sweep Sheet Flue 10662201 10662202 10662203 10662204 10662205 10662206 10662207 10662208 10662209 Collector 48 Base Tile Support 10602301 10602302 10602303 10602304 10602305 10602306 10602307 10602308 10602309 69 Tube Assembly Copper 106659...

Page 32: ...eller B G 1522 5 A0058400 A0058400 A0058400 Automatic Reset Temp Limit Switch E0014400 Manual Reset High Gas Pressure Switch E0023300 Manual Reset Low Gas Pressure Switch E0023500 Alarm Bell 110 Volts A0014200 Outdoor Reset Single Stage 30 Bulb E0067600 Outdoor Reset Two Stage 30 Bulb E0084200 Low water Cut off Electronic Manual Reset E0067900 Low water Cut off Electronic Automatic Reset With Test...

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