Sterling Comprehensive Manual for Unit Heater Wiring and Installation Guide

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ELECTRICAL CONNECTIONS

HAZARDOUS VOLTAGE! DISCONNECT ALL ELECTRIC POWER INCLUDING REMOTE DISCONNECTS BEFORE SERVICING. Failure to disconnect power before servicing can cause severe personal injury or death.

Figure 5a -

Low-voltage T

Thermostat Wiring

Single Stage

Figure 5b -

Low-voltage

Thermostat Wiring

Two Stage

Standard units are shipped for use on 115 volt, 60 hertz, single phase electric power. The motor name-plate and electrical rating of the transformer should be checked before energizing the unit heater electrical system. All external wiring must conform to the latest edition of ANSI/NFPA No. 70, United States National Electrical Code, and applicable local codes; in Canada, to the Canadian Electrical Code, Part 1, CSA Standard C22.1.

Figure 5c - T834H-1009 or T834H-1017 Thermostat Wiring

Honeywell

 

T834H-1009

 

 

or

 

T834H-1017

 

Thermostat

 

W

R

 

 

R

G W1 W2

 

G

 

 

 

D6922B

Do not use any tools (i.e. screwdriver, pliers, etc.) across terminals to check for power. Use a voltmeter.

It is recommended that the electrical power supply to each unit heater be provided by a separate, fused, and permanently live electrical circuit. A disconnect switch of suitable electrical rating should be located as close to the gas valve and controls as possible. Each unit heater must be electrically grounded in accordance with the latest edition of the United States National Electrical Code, ANSI/NFPA No. 70, or CSA Standard C22.1. Refer to Figures 5a, 5b, 5c, 5d and 5e.

THERMOSTAT WIRING AND LOCATION:

NOTICE: The thermostat must be mounted on a vertical, vibration-free surface, free from air currents, and in accordance with the furnished instructions.

Mount the thermostat approximately 5 feet (1.5m) above the floor, in an area where it will be exposed to a free circulation of average temperature air. Always refer to the thermostat instructions, as well as our unit wiring diagram, and wire accordingly. Avoid mounting the thermostat in the following locations:

1.Cold Areas - Outside walls or areas where drafts may affect the operation of the control.

2.Hot Areas - Areas where the sun's rays, radiation,

or warm air currents may affect the operation of the control.

3.Dead Areas - Areas where the air cannot circulate freely, such as behind doors or in corners.

THERMOSTAT HEAT ANTICIPATOR ADJUSTMENTS: The initial heat anticipator setpoint should equal the thermostat's current amperage draw when the unit is firing. This setpoint should be measured for the best results. Use the recommended ranges for a guide. If further information is needed, consult your thermostat manufacturer's instructions.

Recommended heat anticipator settings:

Unit Size:

30 thru 200

250 thru 400

 

 

 

 

For Tubular Units:

0.35 Amps

0.65 Amps

 

 

 

 

NOTICE: The start-up fan delay should not exceed 30 seconds from a cold start.

IMPORTANT: For all wiring connections, refer to the wiring diagram shipped with your unit (either affixed to the side jacket or enclosed in the installation instructions envelope). Should any original wire supplied with the heater have to be replaced, it must be replaced with wiring material having a temperature rating of at least 105° C.

Should any high limit wires have to be replaced, they must be replaced with wiring material having a temperature rating of 200° C minimum.

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Contents Receiving Instructions Tubular GAS Fired Direct Spark Propeller Unit HeatersDescription Table of ContentsGeneral Safety Information Dimensional Drawing Tubular Propeller Unit Heater Installation Installation GAS Piping Pipe SizingGas Pipe Size Gas Piping Requirements Pipe InstallationLow-voltage T Thermostat Wiring Single Stage Two Stage Thermostat Wiring and LocationElectrical Connections Electrical Connections Tubular Unit Sizes with Optional 2 Stage Ignition Venting Vertically Vented Unit Heaters CategoryVenting Categories Structure Termination Locations Horizontally Vented Unit Heaters CategoryVenting Venting Venting Operation Explanation of Controls See FigureShut Down Primary AIR Shutter Adjustment GAS Input RateMain Burner Orifice Schedule Natural GAS Propane LP GAS Tubular Unit Heater High Altitude DerationSymptoms Possible Causes Corrective Action Tubular Propeller Troubleshooting GuideRealign power ventor wheel Check for continuous 115v on terminal LED Status Indicates CHECK/REPAIR Maintenance Periodic ServiceNever over oil the motor or premature failure may occur Power Vented Tubular Propeller Unit Heaters Limited WarrantyPropeller Parts Heat Exchanger AssemblyTurbulator/High Limit Location Power Venter AssemblyWith power and gas on With power and gas offPRE-INSPECTION Information General