A. O. Smith NW-150 User Manual
Commercial Electric Hot Water Boilers
A. O. Smith’s Electric Boilers are designed for demanding hydronic and industrial heating
needs. A wide variety of available electrical inputs and voltages allow the units to be
perfectly matched to the heating requirements of the application and the available
electrical services.
FEATURES
MODULATING STEP CONTROL
input to match load through progressive sequencing of steps. Standard on models with 90kW
or above (optional below 90kW).
INCOLOY IMMERSION HEATERS
immersion heater) have incoloy sheathing, provides excellent protection against oxidation and
scaling. The input ranges from 45kW to 6,000kW (see accompanying chart).
OPTIONAL GOLDENROD® ELEMENTS
24K gold plated element. Goldenrod Elements provide long-life and fi ve times the scaling resistance
of standard incoloy elements. Goldenrod Elements carry a three-year warranty against failure due
to scale.
FUSING -
cartridge-type fuses protect all elements and contactors.
Control and power circuit fusing to meet the National Electrical Code. 100,000 amp I.C.
PILOT SWITCH AND LIGHT
by interrupting power to control circuit. Pilot light indicates when control circuit
is energized.
MAGNETIC CONTACTORS
LOW WATER CUTOFF
in the event of low water condition.
- Probe type, electric low water cutoff prevent energizing of elements
- A solid state modulating step control modulates heat
- Heavy duty medium watt density elements (3 per
- All NW models are available with the Goldenrod
-
Permits manual starting and stopping of heater
- Heavy duty UL rated for 100,000 cycles.
NW-37
through
NW-670
®
120 VOLT CONTROL CIRCUIT
ASME CODE CONSTRUCTION
Vessels with maximum working pressure of 160 psi or less (standard design is for 125 psi) at 240°F
maximum temperature bear the “H” symbol per Section IV of ASME Code. Vessels with greater
than 160 psi working pressure or higher than 240°F operating temperature will bear the “S” symbol
per Section I of ASME Code.
UL LISTED
- All boilers are UL listed per Underwriters’ Laboratories Standard No. 834.
- Powered by fused transformer.
- All vessels manufactured to applicable ASME Code.
ONE YEAR LIMITED WARRANTY
Q
For complete warranty information, consult written warranty.
OTHER STANDARD FEATURES
Q
Two high temperature limit controls
Q
Cabinet has a baked powder coat fi nish
Q
Rectangular jacket made with 18 gauge (minimum) steel
Q
3” fi ber glass insulation
Q
Color coded circuitry for easier servicing
Q
Standard voltages include 208, 240, 480 and 575 volt, single or three-phase
Q
Factory installed terminal block(s)
Q
Combination Temperature/Pressure Gauge
Q
Boiler drain valve
Q
CSA Certifi ed and ASME Rated T&P Relief Valve
*Model shown with optional accessories
May 2012R
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Commercial Electric Hot Water Boilers
UL MINIMUM CLEARANCE REQUIRMENTS:
24” ALL SIDES, 12” TOP
NOTE: ALLOW 30” CLEARANCE FOR HINGED CONTROL
COMPARTMENT DOORS.
ELEMENTS CAN BE CHANGED WITH 24” CLEARANCE.
AN ADDITIONAL CONTROL PANEL IS REQUIRED ON
UNITS ABOVE 500kW RATED AT 208 OR 240 VOLTS.
MODELS: NW-37, NW-60, NW-96 AND NW-150
May 2012R
www.hotwater.com
MODELS: NW-220, NW-334, NW-400, NW-500 AND NW-670
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