State Industries SUF100199, SUF100150 Ground HOT Neutral, Blower Motor Wires Black White RED, AI1

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ULTRAFORCE COMMERCIAL GAS WATER HEATER

SUF 120 thru 400 SERVICE HANDBOOK

VARIABLE FREQUENCY DRIVE – SUF 400

The Ultra Force SUF 400 model has a variable frequency drive (VFD) that controls the rpm of the blower motor. The VFD receives a signal from the central control board that instructs the VFD to transmit the proper frequency to the blower to produce the proper blower speed and proper input.

Three conditions must be met for the frequency drive to start the blower:

1.120VAC must be supplied to the VFD 120VAC input.

2.The ignition control board closes an enable circuit – terminals LI1 and +15V

3.The ignition control board sends a 1-10VDC instruction – terminals 0V and AI1. See table on the next page for voltage and frequency information.

GROUND HOT NEUTRAL	VARIABLE FREQUENCY DRIVE

G

R/L1

155

N

BLOWER MOTOR WIRES BLACK WHITE RED

U/T1

V/T2

W/T3

NOTE: BE SURE TO MATCH WIRE

COLORS WHEN CONNECTING BLOWER

WIRES OR BLOWER MAY RUN

BACKWARD AND CAUSE A FAULT.

RC	RA	0V	AI1	+5V	DO	LI1	LI2	LI3	LI4	+15V
1-10 VDC Speed Instruction						Enable Disable Circuit

State Water Heaters – Technical Training Department 33

Ashland City, Tennessee © 2009

Servicing should only be performed by a Qualified Service Agent

198152-002

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Contents Service Handbook Table of Contents Ultraforce Commercial GAS Water HeaterIntroduction QualificationsTools Required Digital MultimeterGAS Pressure Specifications General InformationAdjustment Procedure GAS Pressure SUF120 and 150 Models High Altitude Installations SUF 120High Altitude Installation GAS OrificeHigh Altitude Adjustment SUF 300,400 SUF 300,400Installation Tips SUF 300 Venting Tables SUF 300,400 Venting Tables SUF 120Vent Length Table Equivalent Feet Meters 120 through Vent Length Table Equivalent Feet Meters 300,400Venting ALL Models Single Pipe Power Vent Using Room AIR Venting ALL Models TWO Pipe Direct Vent Using Outside AIR Vent Termination Direct Vent ALL Models Direct Venting ALL Models Control Overview ALL Models Status Description IconAdjusting Tank Temperature Operating SET Point Differential DisplayChanging the Display Units Fault and Warning Conditions Advanced Diagnostic Information Access to the Current Fault or Warning Viewing Information About the Water Heater Control Sequence Typical ALL Models Control Sequence Flow Chart Controls Central Control Board CCB Remove these Screws to release CoverControls GAS Valve SUF SUF 120 thru 400 Service Handbook Controls GAS Valve SUF 199 Important Note High Altitude InstallationSupply gas pressure Controls GAS Valve , Orifice CHART- SUF300,400 Orifice Chart SUF 300,400Controls Pressure Switches ALL Models Blocked Outlet Proving SwitchTop View of Pressure Switches Controls Pressure Switches SUF 300,400 Blocked Inlet Pressure Switch Odel PressureUltraforce Commercial GAS Water Heater Control Timing HOT Surface Igniter / Flame Sensor / Control TimingFlame Sensor Blower Speed Control SUF 199 ModelAI1 Blower Motor Wires Black White REDGround HOT Neutral LI1 LI2 LI3 LI4SUF Variable Frequency Drive Blower Speed and Pressure ReadingsVoltage Frequency Speed Instructions VFD Model 400Wiring Diagram SUF 120 Wiring Diagram SUF Tennessee Waltz Parkway Ashland City, TN