A.O. Smith VF VB 500 Instruction Manual Download Page 47

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lines with air or water and clear or replace the blocked portions 

of the line as necessary. Note that areas of the drain line which 

include a sag or low spot in the line will also form a condensate trap 

which can be removed by levelling the tube and does not indicate 

a blocked system.

Inspect the metal vent drain and vent collector drain connectors 

at six month inter vals.  Remove the hoses from the connections, 

then check with a small wooden dowel or plastic rod passed up 

through the metal con nection to insure the passage is clear, 

using caution to not bend or damage the connector. Call a 

qualified service agent to inspect and correct the problem if any 

obstructions are found in the connectors.  Replace all hoses and 

clamps immediately after inspec tion and before starting the boiler 

in accordance with the Lighting and Operating Instructions. 

DO 

NOT OPERATE THE BOILER UNLESS ALL CONDENSATE 

DRAIN LINES ARE PROPERLY CONNECTED AND WORKING.  

When a means to neutralize condensate has been installed 

you must also follow operating, inspection and maintenance 

procedures specified by the manufacturer of the product.  Inspect 

the installed device to insure that it does not cause condensate 

to remain in the boiler or vent for any reason.

VENTING MAINTENANCE

It is recommended that the intake and exhaust piping of the 

appliance be checked every 6 months for dust, condensate leakage, 

deterioration and carbon deposits.

Qualified  service  agent  should  follow  this  procedure  when  the 

boiler’s intake and exhaust piping need cleaning:

1.  Turn off the electrical power, and manual gas shut-off.

 

• 

Allow boiler parts to cool before disassembly.

2.  Remove the vent pipe.

 

  Check parts and chimney for obstructions and clean as  

   necessary.

3.  Remove burner from boiler and other metal parts as required  

  to clean as necessary.

 

  Refer to parts list for disassembly aid.

4.  Clean and reinstall the parts removed in steps 2 and 3.

 

  Be sure the vent pipe has a minimum upward pitch of 1/4"  

    per foot (2cm/m) of length and is sealed as necessary.

5.  Restore electrical power and gas supply to boiler.

 

  Check for gas leaks and proper boiler and vent operation.

HEAT EXCHANGER PREVENTATIVE MAINTENANCE

In most water supply systems solids exist. As the water is heated, these 

tend to drop out depositing as scale or lime. This scale must be removed 

before the heat exchanger tubes become blocked.

DELIMING

The amount of calcium carbonate (lime) released from water is 

in direct proportion to water temperature and usage.  The higher 

the water temperature or water usage, the more lime deposits are 

dropped out of the water.  This is the lime scale which forms in 

pipes, boilers and on cooking utensils.
The usage of water softening equipment greatly reduces the 

hardness of water. However, this equipment does not always 

remove all of the hardness (lime). For this reason it is recommended 

that a regular schedule for deliming be maintained.
The time between cleaning will vary from two to six months 

depending upon water conditions and usage. A change 

of approximately 5

°

F  (3°C)  in  the  normal  temperature  rise 

through the boiler is usually an indication that scale should 

be removed.  For long life, copper or brass is recommended 

for all valves, pipe and fittings.

TUBE CLEANING PROCEDURE MECHANICAL 

REMOVAL OF DEPOSITS

Establish a regular inspection schedule, the frequency depends 

on the local water conditions and severity of service. Do not let 

the tubes clog up solidly. Clean out deposits over 1/16” (1.6mm) 

thickness.

 

To service heat exchanger tubes, remove return header casting on 

the side opposite the water connections. Use a U.S. standard 5/8” 

deep socket ratchet to remove the nuts, exposing the tube ends.  

Inspect to ensure tubes are free of scale and deposits. If scaled, 

remove deposits with a stiff wire brush or mechanical tube cleaner 

to bare metal. Reinstall return header casting. Flush system.
Note: Removal of the heat exchanger is not required.

REPLACEMENT PARTS

Replacement parts may be ordered through A. O. Smith dealers, 

authorized servicers or distributors.  Refer to the Yellow Pages for 

where to call or contact (in United States) the 

A. O. Smith Water 

Products Company, 500 Tennessee Waltz Parkway, Ashland 

City, TN 37015, 1-800-433-2545 or (in Canada) A. O. Smith 

Enterprises Ltd., 768 Erie Street, Stratford, Ontario, Canada 

N5A 6T3, 519-271-5800.

 When ordering parts be sure to state 

the quantity, part number and description of the item including the 

complete model and serial number as it appears on the product. 

Refer to the parts lists for more information.

For Technical Assistance call A. O. Smith Technical Information 

Center at 1-800-527-1953.

Summary of Contents for VF VB 500

Page 1: ...ilding Immediately call your gas supplier from a neighbor s phone Follow the gas supplier s instructions If you cannot reach your gas supplier call the fire department Installation and service must be...

Page 2: ...known to the State of California to cause cancer birth defects or other reproductive harm and requires businesses to warn of potential exposure to such substances This product contains a chemical know...

Page 3: ...3 GENERAL SAFETY...

Page 4: ...al Power 120v 60hz and 30 amps Models VB VW 500 VB VW 750 VB VW 1000 Dimensions inches mm inches mm inches mm Flue Outlet Diameter 6 152 6 152 6 152 Air Intake Diameter 4 102 4 102 4 102 Water Inlet 2...

Page 5: ...9 42 159 2 1 0 6 32 121 1 8 0 5 110 416 4 3 1 3 12 7 32 121 1 8 0 5 40 22 VB 1000 85 322 3 9 1 2 56 212 2 8 0 9 42 159 2 3 0 7 120 454 4 9 1 5 14 8 42 159 2 3 0 7 40 22 Model No Input Rating Btu hr Ou...

Page 6: ...d Ability 10 Location 10 Panels and Covers 10 Chemical Vapor Corrosion 11 Installtion Clearances 11 Leveling 11 Air Requirements 11 Unconfined Space 11 Confined Space 11 Fresh Air Openings for Confine...

Page 7: ...N EXPOSED TO FLOODING IT MUST BE REPLACED Liquefied Petroleum Gas Models Boilers for propane or liquefied petroleum gas LPG are different from natural gas models A natural gas boiler will not function...

Page 8: ...S is a normally closed pressure switch that opens when the air intake is blocked If the BIS is activated check and clear the intake of any obstructions The blocked flue pressure switch BFS activated w...

Page 9: ...emperature Probe allows a boiler to sense the actual water temperature inside the storage tank or hydronic heating loop The boiler will modulate its firing rate in response to the actual system temper...

Page 10: ...g cartridge or linkage T P relief valve should have a temperature rating of 210 F 99 C a pressure rating not exceeding lowest rated working pressure of any system compo nent and a discharge capacity e...

Page 11: ...sure adequate air supply Unusually Tight Construction In unconfined spaces in buildings infiltration may be adequate to provide air for combustion ventilation and dilution of flue gases However in bui...

Page 12: ...ThroughTwoHorizontalDucts FIGURE 9C The confined space should be provided with two permanent horizontal ducts one commencing within 12 inches 300 mm of the top and one commencing within 12 inches 300...

Page 13: ...osure See Figure 9E Each opening should communicate directly with an additional room s of sufficient volume so that the combined volume of all spaces meets the criteria for an Unconfined Space Each op...

Page 14: ...into building or combustion air inlet to any other appliance 6 inches 15 cm for appliances up to 10 000 Btu hr 3 kW 12 inches 30 cm for appliances between 10 000 Btu hr 3 kW and 100 000 Btu hr 30kW 3...

Page 15: ...let into building or combustion air inlet to any other appliance 6 inches 15 cm for appliances up to 10 000 Btu hr 3 kW 12 inches 30 cm for appliances between 10 000 Btu hr 3 kW and 100 000 Btu hr 30...

Page 16: ...sing TWT to exhaust flue prod ucts and PVC piping to bring combus tion air to the boiler from the outside see Figures 12 and 12C 4 Vertical Direct Vent using a vertical vent termination to exhaust flu...

Page 17: ...direct vent installations Standard minimum vertical vent lengthis7feet 2 1m plusBoot Tee SeeFigures11 12A 12B and 12C for differences between standard and direct vent installations 3 An AL 29 C Vent V...

Page 18: ...r parapet it must extend a minimum of 2 610mm above the wall or parapet Joints are not joined to show vent pipe orientation FIGURE 11 VERTICAL TERMINATION FIGURE 11A HORIZONTAL THROUGH THE WALL TERMIN...

Page 19: ...d carbon monoxide detector with an alarm shall be installed APPROVED CARBON MONOXIDE DETECTORS Each carbon monoxide detector as required in accordance with the above provisions shall comply with NFPA...

Page 20: ...nt terminal NOTES If the exhaust vent terminal is within 10 3 0m of a wall or parapet it must extend a minimum of 2 610mm above the wall or parapet Joints are not joined to show vent pipe orientation...

Page 21: ...OR PARAPET ON SIDEWALL VENT INSTALLATION REFER TO FIGURE 9F FOR SPACING SPECIFICATIONS FOR EXHAUST AND AIR INTAKE PIPE INSTALLATIONS CLEARANCES SUPPORT ETC REFER TO FIGURES 12 AND 12A VERTICAL AIR IN...

Page 22: ...red by the warranty 2 EXPANSION TANK If the system is of the closed type install an expansion tank as shown in Figure 13 The sizing of the expansion tank for a closed system is very important and is d...

Page 23: ...ra tion Pipe joint compounds soldering paste grease on tubing and pipe all tend to contaminate a system Failure to flush contaminants from a system can cause solids to form on the inside of boiler exc...

Page 24: ...a suitable main manual shut off valve must be installed in a location complying with those codes Before attaching the gas line be sure that all gas pipe is clean on the inside To trap any dirt or for...

Page 25: ...REQUIRED INSTALL IN PLACE OF THE DRAIN VALVE SHOWN DANGER TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERATURE AT FIXTURES IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE BOOSTE...

Page 26: ...ES ARE NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT ADD AN ANTI SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES SEE TABLE 8 ONE VF MODEL VW HOT WATER SUPPLY BOILER WITH VERTICAL TANK FIGURE 14 INSTALL I...

Page 27: ...AFE USE TEMPERATURE AT FIXTURES IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT ADD AN ANTI SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES SEE TABLE 8 FIGURE 15 INSTALL...

Page 28: ...3 GREEN GROUND 4 2 TANK PROBE OR 2 ENABLE DISABLE Enable disable can also be used with a 24 volt thermostat Do not use tank probe when using thermostat These connections shall be made at the rear of...

Page 29: ...132 000 13 728 000 12 636 000 11 700 000 11 232 000 10 452 000 9 360 000 8 580 000 7 800 000 7 176 000 kW 10 508 7 219 5 848 4 980 4 432 4 021 3 701 3 427 3 290 3 061 2 741 2 513 2 284 2 102 TABLE 6...

Page 30: ...30 Wiring Diagram FIGURE 17 CONNECTION DIAGRAM...

Page 31: ...31...

Page 32: ...32 FIGURE 18 SCHEMATIC DIAGRAM VB VW 500 750 1000 SCHEMATIC DIAGRAM...

Page 33: ...desired system pressure Close bypass valve and permit pressure to be established by the pressure reducing valve 2 Vent all high points in system to purge system of air Provisions should be made to per...

Page 34: ...further adjustments on the outlet and bypass valves until the desired inlet and outlet water temperatures are reached MANIFOLD PRESSURE CONNECTIONS Take the manifold pressure refer to Table 1 by remo...

Page 35: ...ure On Yes Off No Switch 8 Modulation On NOTE If the unit powers up with the number of stages selected by dip switches exceeding the number of FCBs the MCB will detect this condition and go into a har...

Page 36: ...36 LIGHTING OPERATION INSTRUCTIONS FOR MODELS VB VW 500 750 AND 1000...

Page 37: ...e cap on the gas regulator using a slotted screwdriver This will expose the offset adjustment screw Using a TORX T40 or a 5mm hex wrench carefully adjust the low fire gas setting to achieve the CO2 le...

Page 38: ...is missing or shorted the flame will not be detected OUTPUTS FROM MCB Relay Contact Output Alarm MCB 24VAC optional Provides electrical power to operate an external alarm This can be an audio device...

Page 39: ...splayed 4 The system then compares the temperature read from the controlling probe inlet or tank to the setpoint temperature If the temperature is less than the operating setpoint minus the differenti...

Page 40: ...The MCB has 5 possible states and the FCB have 9 The normal MCB states sequence is to move from Idle to Pre Circulate when a call for heat is initiated Once heat has been satisfied or the Thermostat i...

Page 41: ...ch error has occurred The system waits in this state until the MCB sends a command to clear the error and the system returns to the idle state Cold Purge State Cold purge occurs when the MCB micro com...

Page 42: ...fo Screen Displays the following information Elapsedhoursofoperation Totaltimesystemhasbeenpoweredup Number of running minutes Number of minutes system has been in the run mode kBtu rating of the boil...

Page 43: ...es that a fault has been detected and the system has stopped running It is on continuously for soft faults and flashes for hard faults The Yellow LED indicates that the boiler is in a ready mode waiti...

Page 44: ...ote The MRHL can be checked by disconnecting the outlet probe from the MCB and reading the resistance across the two active pins on the connector at the end of the probe cable The value should be appr...

Page 45: ...tion of the servo pressure regulator Replace the valve and add a gas filter in front of the new valve preventative maintenance This is a pre mix burner system The flame is not supposed to be directly...

Page 46: ...er adapter by first removing the four 4 bolts and subsequently the blower gas kets The blower should be free to move at this point FOR DIRECT VENT UNITS It is necessary to loosen and slide the rubber...

Page 47: ...ystemssolidsexist Asthewaterisheated these tendtodropoutdepositingasscaleorlime Thisscalemustberemoved before the heat exchanger tubes become blocked Deliming The amount of calcium carbonate lime rele...

Page 48: ...48 notes...

Page 49: ...49 notes...

Page 50: ...50 notes...

Page 51: ...is boiler under state or provincial law are limited to one 1 year duration for the boiler or any of its parts Some states and provinces do not allow limitations on how long an implied warranty lasts s...

Page 52: ...52 500 Tennessee Waltz Parkway Ashland City TN 37015 Phone 800 433 2545 www hotwater com E Mail parts hotwater com...

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