Laars VW-PW, Installation, Operation And Maintenance Instructions

Page 1: ...tallation 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 elec...

Page 2: ...r Heater Temperature Control 20 3 3 2 Internal Water Heater Temperature Control 20 3 4 Adjustment for Minimum Input Rate models with modulating gas valve 21 3 5 Hi Limit Switch Checkout 22 3 6 Shut Down Procedure 22 SECTION 4 Maintenance 4 1 General Instructions 22 4 2 Replacement of Gas Controls 22 4 3 Heat Exchanger 24 4 3 1 Inspecting the Heat Exchanger 24 4 3 2 Cleaning the Heat Exchanger 24 S...

Page 3: ... are shipped in separate 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 The warranty does not cover damage caused by improper installation operation or field modification 1 3 Technical Assistance Consult Laars or...

Page 4: ...evices for Automatically Fired Heaters ANSI ASME CSD 1 Any changes to the heater gas controls gas orifices wiring or draft diverter may void the warranty If field conditions require a change to any of the above consult the factory All gas fired products require correct installation to assure safe operation The requirements for heaters include the following 1 Field assembly of drafthood or vent cap...

Page 5: ...s fired appliances within the enclosure Alcove Installation acceptable An alcove suitable for the installation of a heater is a restricted section of a room not separated from the room by a door or partition and which meets the minimum clearances specified in this manual When the ceiling height exceeds 8 feet you are only allowed to consider 8 feet when calculating the total volume of the enclosur...

Page 6: ...nger Roof Base Rail 20 Gauge Galvanized Sheet Metal Cap Roofing Avoid locations where wind deflection off nearby structures might cause wind loading and downdraft conditions Where downdraft conditions exist locate the heater at least 3 feet 0 91 m from the structure 2 3 3 Flooring Typical Installation Do not install the heater directly on carpeting without placing a non combustible platform betwee...

Page 7: ... CGA B149 NOTE Check with louver manufacturers for net free area of louvers If screens or louvers are installed add 50 percent for each screen louver to the net free area Check all local codes applicable to combustion air 2 4 1 Outdoor Air Supply When combustion air comes directly through an outside wall each opening must have a minimum free area of at least one square inch for each 4 000 BTU h in...

Page 8: ...the venting system is necessary qualified personnel should design the installation following good engineering practices and all applicable codes A suitable draft switch must be wired into the heater control circuit at the terminal designated Field Interlock to keep the heater from firing unless there is a positive draft 2 5 2 Replacement of Existing Heater When a heater is removed from a common ve...

Page 9: ...Mighty Therm Volume Water Heaters Page 9 Figure 15 Heat exchanger reversal Figure 16 Flue collector Holddown Clamps ...

Page 10: ...s free from the temperature control see Figure 18 c Pull the sensing bulbs out of the temperature control d Gently pull the capillary tubes into the control compartment e Pull the temperature sensing bulb out of the header and temporarily route it to the front of the heater 13 Use a pair of diagonal cutters to cut the plastic tie around the wire bundle in the control compartment 14 On the terminal...

Page 11: ...Check to make sure the wiring is not pinched against sharp edges or resting on the collector assembly 36 Replace the two flue collector holddown clamps 37 Replace the top assembly and fasten it with the hex head screws 38 Replace the front cover 39 Reinstall the vent cap or drafthood if one was removed Hardness Grains per Parts Category Gallon per Million Soft 1 through 7 5 17 through 128 Normal 7...

Page 12: ... Soft 34 2 1 13 3 4 1 19 11 Normal 34 2 1 13 3 4 1 19 11 Hard 46 2 9 23 4 7 1 14 8 4 Soft 17 0 7 11 1 3 4 37 21 Normal 17 0 7 11 1 3 4 37 21 Hard 23 1 5 19 5 5 9 27 15 Pressure drop includes head loss of heat exchanger and through 30 feet 9 1 m of pipe and normal fittings when heater is installed with storage tank Pipe and fittings are assumed to be 1 1 2 inch 38 mm Main Circulating Loop With Own ...

Page 13: ...Mighty Therm Volume Water Heaters Page 13 Figure 22 Hot water supply with horizontal tank Note Heavy line indicates heater to tank circulation loop Figure 21 Hot water supply with vertical tank ...

Page 14: ...intermittently resulting in rapid scaling of the heat exchanger 4 If designed for floor mounting install pump securely on concrete block or pad at least 6 inches 152 mm above floor level This will prevent flooding of the motor when the floor is washed 5 Do not suspend floor mounted pumps from piping 6 Plumb piping to avoid putting strain on the pump casing 2 6 5 Pump Requirements The VW heater doe...

Page 15: ...d 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 Incorrect installation can cause rapid failure of water tanks due to electrolysis Tanks must be installed with dialectric connections to electrically isolate the tank from stray current Note that use of brass or bronze connectors does not replace the need for dialectric connecti...

Page 16: ...uctions for converting the heater Changing burner and or pilot orifices is prohibited The installer must add and sign a gas conversion tag when the conversion is made 1 Gas piping installation must be in accordance with the latest edition of ANSI Z223 1 In Canada the installation must be in accordance with CAN1 B149 1 or 2 and all local codes that apply 2 Check the rating plate to make sure the he...

Page 17: ...automatically lights the burner Do not try to light the burner by hand sure heater is wired for 120 volts alternating current VAC If 240 VAC contact local factory representative or Laars 2 Wire the heater and pump exactly as shown in the wiring diagram supplied with the heater See Figure 26 and 27 for a typical example of a wiring diagram 3 Electrically interlock the pump and heater so the heater ...

Page 18: ...re 26 Typical example of wiring schematic System 1 IGNITION SYSTEM NO 1 STANDING PILOT ON OFF OR MECHANICAL MODULATION Volume Water Heaters 325 400 Version B Natural or Propane Gas PUMP INCLUDED ON PW MODELS FIELD SUPPLIED ON VW MODELS ...

Page 19: ...igure 27 Typical example of wiring schematic System 12 IGNITION SYSTEM NO 12 ELECTRONIC IGNITION ON OFF OR MECHANICAL MODULATION Volume Water Heaters 325 400 Version B Natural or Propane Gas PUMP INCLUDED ON PW MODELS FIELD SUPPLIED ON VW MODELS ...

Page 20: ...on 130 F 54 C when shipped from the factory This is the preferred starting point for setting the temperature control If the unit is equipped with an automatic reset high limit set the automatic reset high limit 20 F 11 C above the outlet temperature to avoid nuisance lockouts Set the manual reset high limit 5 F 3 C above the automatic reset high limit For units that only have a manual reset high l...

Page 21: ...ual reset high limit to 83 C 80 C 3 C 3 4 Adjustment for Minimum Input Rate models with modulating gas valve Adjust the red knob on the modulating gas valve to the dial number for the desired water temperature see Table 7 Adjusting the red knob to number 1 sets the gas flow rate to minimum The control is factory set at 2 which is satisfactory for most installations Figure 30 Gas valve burner repla...

Page 22: ... Keep the heater area clear of combustible material gasoline and other flammable liquids and vapors 6 Be sure all combustion air and ventilation openings are not blocked 7 Check for black carbon soot buildup on the external surfaces of the heat exchanger every 6 months 8 Do not use the heater if any part has been under water Replace anypart of the control system and any gas control which has been ...

Page 23: ...y and push it away from the manifold until it is clear of the orifice Slide the burner to be replaced out of the burner tray see Figure 31 12 To replace the gas burner insert the burner into the slot at the rear of the burner tray line it up with the proper orifice and snap it into position 13 To replace the pilot burner install the pilot assembly on the new pilot burner and install it in the burn...

Page 24: ...m Laars 4 Ream the insides of the tubes see Figure 33 5 Pull the reamer out frequently to remove lime powder and prevent the drill from binding in the tube 6 Install new gaskets Do not reuse the old ones 7 Tighten the header bolts progressively starting with the two center bolts Maximum torque is 20 inch pounds 27 Nm Do not over torque 8 Pressure test the heat exchanger for leaks with city water s...

Page 25: ...lace the 1 8 inch 3 2 mm NPT fitting with the original plug 5 2 Electrical Troubleshooting This section describes procedures for checking the electrical power and control components of the heater Read all of these procedures before starting repairs Problems with heaters not firing are usually caused by something reducing water flow through the heater causing the protective switches in the heater s...

Page 26: ... loads e g air conditioners compressors on the circuit to high pump load or to an electrical utility company problem Figure 36 Testing the manual reset hi limit switch Figure 37 Testing the fusible link Finding a loose connection or a charred wire can save a lot of time and money 5 Check the fuse inside the black twist lock fuse holder If it is burned replace it with a 2 amp fuse Part No E0084400 ...

Page 27: ...witch is found to be defective replace the flow switch To test the flow switch 1 Remove cap from flow switch 2 Touch a voltmeter lead to each terminal of the flow switch 3 If the voltmeter reads voltage at each of the terminals the switch is good 4 If there is no voltage at one terminal it indicates an open switch Check flow switch paddles to determine if they are broken missing or frozen Replace ...

Page 28: ... on 2 Make sure the temperature control is turned far enough to call for heat There will be a loud clicking noise indicating the pilot electrode is sparking 3 If no sparking is heard pull the ignition lead from the ignition control and hold the bare terminal 1 8 to 3 16 inch 3 2 to 4 8 mm from the ignition stud with a pair of insulated pliers see Figure 40 4 If a spark does not jump the gap replac...

Page 29: ... Testing for Pilot Burner for spark ignition When the pilot burner lights the sparking should stop and the main burners should fire If the sparking continues and the main burners do not fire 1 Check all wire connections ignition cable and using a mirror make sure there is a pilot flame 2 Make sure the wiring agrees with the wiring diagrams found on the inside of the heater 3 Check for sparking at ...

Page 30: ...off the wiring could be at fault Repair or replace as necessary 5 2 17 On Off Main Burner Cycling The main burners cycling on and off can be caused by 1 Poor wind conditions on an outdoor installation 2 Pilot components out of position 3 Low gas pressure causing an improper pilot flame The pilot flame may appear to be all right until the main burners come on then the pilot flame shrinks An undersi...

Page 31: ... Lightweight Composite Tile Replacement Kit 400 R0325305 38 Tile Cover Side 10167300 39 Tile Cover Front and Rear 10314902 05 40 Insulation Jacket 10458902 05 WATER SYSTEM 41 Bracket Heat Exchanger 10457000 42 Heat Exchanger Tube Assy Copper Thickwall R0095502 05 Cupronickel Thickwall R0095602 05 43 Plug 1 4 Inch NPT P0026800 44 In Out Header Cast Iron S0079100 2 Pass 10593700 Bronze S0081700 4 Pa...

Page 32: ...ervice Advisors 20 Industrial Way Rochester NH 03867 603 335 6300 Fax 603 335 3355 Applications Engineering 1869 Sismet Road Mississauga Ontario Canada L4W 1W8 905 238 0100 Fax 905 366 0130 www Laars com Litho in U S A Laars Heating Systems 0912 Document 2051E ...