A.O. Smith VB/VW- 1000 Boiler User Manual


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10
The Discharge Pipe:
• Shall not be smaller in size than the outlet pipe size of the valve, or
have any reducing couplings or other restrictions.
• Shall not be plugged or blocked.
• Shall not be exposed to freezing temperatures.
• Shall be of material listed for hot water distribution.
• Shall be installed so as to allow complete drainage of both the relief
valve and the discharge pipe.
• Must terminate a maximum of six inches above a oor drain or
external to the building. In cold climates, it is recommended that the
discharge pipe be terminated at an adequate drain inside the building.
• Shall not have any valve or other obstruction between the relief valve
and the drain.
Once the boiler is installed and lled with water and the system
is pressurized, manually test the operation of the pressure relief
valve. See the maintenance section of this manual for instructions.
Your local code authority may have other specic safety relief
valve requirements not covered below. If any pressure relief valve
is re placed, the replace ment valve must com ply with the current
version of the ASME Boiler and Pressure Vessel Code, Section
IV (“HEATING BOILERS”).
VW HOT WATER SUPPLY BOILERS, are shipped with a 125 psi
(860kPa) pressure relief valve that must be installed in the water
out let as near to the boil er as possi ble.
This ASME-rated valve has a discharge capacity that exceeds maximum
boiler input rating and a pres sure rating that does not exceed maximum
working pres sure shown on boiler rating plate. In addition, a CSA
design-certiedandASME-ratedtemperatureandpressure(T&P)
relief valve must be installed on each and every water storage tank
inhotwatersupplysystem.TheT&Preliefvalvemustcomplywith
appli cable construction provisions of Standard for Relief Valves for
Hot Water Supply Systems,ANSIZ21.22orCSA4.4.T&Preliefvalve
must be of automatic reset type and not embody a single-use type
fusible plug, 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 exceeding total
input of water boilers supply ing water to storage tank.
LocatetheT&Preliefvalve(a)inthetopofthetank,or(b)inthesideof
thetankonacenterlinewithintheupper6inches(152mm)ofthetop
of the tank, see Figures 14 and 15. The tapping should be threaded in
accordance with the current edition of the Standard for Pipe Threads,
General Purpose(inch),ANSI/ASMEB1.20.1.The locationof, orin-
tendedlocationfor,theT&Preliefvalveshouldbereadilyaccessiblefor
servicing or replacement.
VB HOT WATER HEATING BOILERS, are shipped with a 50 psi
(345kPa)pressurereliefvalve.Thisreliefvalvemustbeinstalled
in the water outlet as near to the boiler as possi ble.
GENERAL
REQUIRED ABILITY
INSTALLATION OR SERVICE OF THIS BOILER REQUIRES
ABILITY EQUIVALENT TO THAT OF A LICENSED TRADES MAN
IN THE FIELD INVOLVED. PLUMBING, AIR SUPPLY, VENTING,
GAS SUPPLY, AND ELECTRICAL WORK ARE RE QUIRED.
LOCATION
When installing the boiler, consideration must be given to proper
location. The location selected should provide ade quate air supply
and be as centralized with the piping system as possible.
If the boiler is installed above radia tion level, a Low Water
Cutoff Device must be installed in the boiler outlet at the time of
installation.
PANELS AND COVERS
Allpanelsandcovers(e.g.controlandjunctionboxcovers;
front,sideandrearpanelsofboiler,seeFigure8)MUSTbein
place after service and/or before opera tion of the boiler. This
will ensure that all gas ignition components will be protected
from water.
TheVFisalow-pressureboiler(CategoryIV)tobeusedaseither
hotwatersupply(domestic/commercialwaterheating)orhotwater
heating(hydronic)application.CategoryIVboilersoperatewitha
positive vent pressure and with a vent gas tempera ture less than
120°F(49°C)aboveitsdewpoint.CategoryIVappliancesare
oftentermed“HighEfciency”appliances.
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