Ao-smith VB/VW-500 User Manual

1WARNING: If the information in thismanual is not followed exactly, a fire orexplosion may result causing propertydamage, personal injury or loss of l

10location. A drain line must not contain any valves between theboiler and the relief valve, or the relief valve and the drain exit. Inaddition, there

11shall be wide enough to allow the boiler to enter or to permit thereplacement of another appliance such as a boiler.LEVELINGEach unit should be chec

12communicating with the outdoors. The installation instructions forconfined spaces in tightly constructed buildings must be followed toensure adequat

13from the horizontal to vertical run. This is where the bottom mostsupport bracket should be located.The Boot-Tee Drain Cover is required in order to

14NOTES: If the exhaust vent terminal iswithin 10’ (3.0m) of a wall or parapet, itmust extend a minimum of 2’ (610mm)above the wall or parapet.Joints

15DIRECT VENT INSTALLATION REQUIREMENTSFollow the guidelines in the “HORIZONTAL INSTALLATIONREQUIREMENTS” section for the exhausting of flueproducts.I

16FIGURE 12. DIRECT VENT HORIZONTAL.FIGURE 12A. DIRECT VENT VERTICAL. CAUTIONDirect venting into dead air spaces such as;alleys, atriums and inside

17FIGURE 12B. DIRECT VENT, VERTICAL VENT TERMINATION WITH HORIZONTAL INTAKE.FIGURE 12C. DIRECT VENT USING TWT WITH VERTICAL INTAKE.Option B (Figures

18SYSTEM INSTALLATIONGENERALIf the system is to be filled with water for testing or otherpurposes during cold weather and before actual operation,care

197. SYSTEM CONTROLLERControlling of these systems is decided mainly by the typeof building system controlling desired. A single boilerinstallation mi

2SAFE INSTALLATION, USE AND SERVICEYour safety and the safety of others is extremely important in the installation, use, and servicing of this boiler.

20This is accomplished by changing two dipswitch settings onthe MCB. First, dipswitch “4” must be set to the “ON” positionto designate the remote prob

21 DANGERTEMPERATURE SETTING SHOULD NOT EXCEED SAFE USETEMPERATURE AT FIXTURES. IF HIGHER PREHEATTEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATEBOOSTER

22To prevent damage, care must be taken not to apply too muchtorque when attaching gas supply pipe to boiler gas inlet.Fittings and unions in the gas

23Table 8. Suggested Pipe Size For Multiple Gas Appliances (Propane Gas).Nominal Maximum Capacity of Pipe in BTU/hr and kW for Gas Pressures of 14 in

24FIGURE 18. CONNECTION DIAGRAM

25

26FIGURE 17 - SCHEMATIC DIAGRAMVB/VW-500, 750 & 1000 SCHEMATIC DIAGRAM

27OPERATIONIMPORTANTOnly qualified personnel shall perform the initial firing of the boiler.At this time the user should not hesitate to ask the start

28The boiler should be located in an area that is inaccessible tothe general public.Never allow small children to use a hot water tap or to draw their

29MCB - Ten Position Dipswitch:Dipswitch configurations are READ ONLY ON POWER UP. These switches are only to be set at the factory or by authorized

3GENERAL SAFETY

30LIGHTING & OPERATION INSTRUCTIONS FOR MODELS VB/VW 500, 750 AND 1000:

31ADJUSTMENTThere must be sufficient load to operate the boiler at high fire toperform the following adjustments. Start the boiler and observeproper o

32INPUTS TO MCBTEMPERATURE SENSORS:Temperature probes (MCB - outlet and either inlet or tank arerequired): The MCB accepts analog temperature inputs f

335. The heating sequence begins by applying power to the pump.6. After a few seconds the blower is turned on for 30-secondpre-purge period of combust

34for a heat request (determined by the Thermostat or controllingprobe inputs). All outputs are off in this state except that if thePost-Circulate tim

35if the blower prover does not activate after 15 seconds. Thistime allows the blower relay to activate, the blower to come upto speed, and the respon

36The software revision level of the MCB.• Current Error Screen:Displays the last error that the system has detected plus atime stamp of when the erro

37TROUBLESHOOTING IGNITION SYSTEMFault Messages and Lockout Status (* = stage number: 1, 2, 3, or 4)FAULT DISPLAYED DESCRIPTION RED LED LOCKOUT“Displ

38TROUBLESHOOTING GAS VALVEProblem: Non-linear CO2 curve on adjusted boiler (deviationmore than 3-6%)1. Possible blockage at the air inlet that preven

39Any safety devices including low water cutoffs used in conjunctionwith this boiler should receive periodic (every six months) inspectionto assure pr

4Minimum clearances to combustibles:• 4” (102mm) rear• 0” (0mm) top & sides• 6” (152mm) ventTABLE 1, GAS AND ELECTRICAL CHARACTERISTICSManifold Pr

40lines with air or water and clear or replace the blocked portions ofthe line as necessary. Note that areas of the drain line whichinclude a sag or

41NOTES

42NOTES

43LIMITED WARRANTYA. O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this boiler:1. If within TEN years af

44500 Tennessee Waltz Parkway, Ashland City, TN 37015Phone: 800-433-2545www.hotwater.com E-Mail: [email protected]

5CAPACITY AND FLOW DATATemperature Rise - °F (°C) 40 60 80 90 100 120 140 Model No. Input Rating Btu/hr Output Rating Btu/hr Water Flow (22) (33) (44)

6This design complies with the current edition of the ANSIZ21.13 low-pressure boiler standard.Compliance under this standard implies that when the bo

7GROUNDING INSTRUCTIONSThis boiler must be grounded in accordance with the NationalElectrical Code and/or local codes. Boiler is polarity sensitive;c

8THE CONTROL SYSTEMThe control system consists of four basic components:1) Modulation Control Board (MCB); 2) Power Distribution Board(PDB); 3) Variab

9WATER TEMPERATURE LIMIT CONTROLSThe “V(B/W)” models incorporate an outlet water probe consistingof two limit controls:1. An adjustable automatic high