st9120 fan timer training module

8/3/2019 ST9120 Fan Timer Training Module

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ST9120U1003Universal ElectronicFan Timer

Training Module


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Product Overview Set Up Installation Troubleshooting Product Cross Reference ST9120 Advantage

ST9120U - What You Will Learn:


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What is the ST9120U Electronic Fan Timer?

A universal electronic fan timer thatintegrates control of all combustionblower and circulating fan operationsin a gas warm air appliance

- Monitors the thermostat for heat, cooland fan demands.

- Runs the induced draft blower motorand runs the circulating fan (up to twospeeds) as needed.

- Monitors limit switch strings andenergizes ignition control.

- Central wiring point for the electricalcomponents of the furnace. Saves time! One part number:

ST9120U1003


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ST9120U Electronic Fan Timer Features

Why choose the Honeywell ST9120U?

Universal application Replaces over 25 existing Honeywell controls

Easy installation DIP switch selectable circulating fan delays

Heat on/off delay Cool on/off delay (cool off fixed at 30 seconds)

Single model services multiple furnaceapplicationsIncluded with the ST9120U:

Wiring information and adapter for the ST9101 Original appliance application Delay timing recommendation

Quality construction for a long service life


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Installation


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Installation of the ST9120U

Location and Mounting

- Mount the ST9120U Electronic Fan Timer in the appliance wiringcompartment or furnace vestibule- Mounting screws provided

Wiring- Make sure that all wiring complies with local codes and

ordinances.- Disconnect power before making wiring connections.


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Set-Up


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Set up of the ST9120U

Setting DIP switches

- Heat fan-on delayOn: 30/60 SecondsStarts timing when main valve energized

- Heat fan-off delayOff: 60/100/140/180 Seconds

Starts timing when main valve is de- energized- Cool fan-on delay

On: 4/30 Seconds Starts with call for cooling

- Cool fan-off delay fixed at 30 seconds

- Post Purge: 5 seconds


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Set up of the ST9120U

Recommendeddip switchsettings areincluded in theinstallationinstructions aswell as theHoneywellResidentialCombustion

Application andSelectionGuide.


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Troubleshooting


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Troubleshooting of the ST9120U

Look for appropriate voltages at the ST9120Uterminals

Check operation and timing of:- Combustion blower- Fan at heating speed

- Fan at cooling speed Check limit operation and system response

Note: The ST9120U schematics show internal switching to clarify operationand assist in troubleshooting.


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Product Cross Reference


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The ST9120U replaces over 25 existing Honeywell controls:

ST9101A1006 ST9120C1020 ST9120C4016 ST9120G2016

ST9101A1014 ST9120C2002 ST9120C4040 ST9120G2024

ST9101A1022 ST9120C2010 ST9120C4057 ST9120G2032

ST9120A1006 ST9120C2028 ST9120C5005 ST9120G4004

ST9120A2004

ST9120C3000

ST9120C5013

ST9120G4012

ST9120B1005 ST9120C3018 ST9120D3009 ST9120G4038

ST9120C1012 ST9120C4008 ST9120G2008


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Where do I find Honeywell universal fan timer cross

reference information?- www.customer.honeywell.com- Honeywell Application Selection and Cross

Reference Guide Form 63-9575

- Honeywell Laminated Truck Visor Form 63-9581- Honeywell Residential Technical Support: 1-800-468-1502


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www.customer.honeywell.com

See Cross Reference Search box in right column.


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ST9120U Advantage

When promoting the ST9120U keep theseadvantages in mind:

- The ST9120U universal control replaces over 25 existingHoneywell controls. This in turn, reduces inventory andsaves time looking for the right part.

- A central wiring point for most of the electrical componentsof the furnace makes installation easy and gets the installeron to the next job faster .

- Easy to set selectable heat and cool on/off settings adapt tothe application.

- The ST9120U makes the choice simple ; one control savestime and money, improving your bottom line .


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ST9120U1003Universal Electronic Fan Timer

Knowledge Test


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Now that you completed this training module, take the

short quiz to test your knowledge.

ST9120U Knowledge Test


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Test

1. The ST9120U Universal Electronic Fan Timer

controls the blower and circulating fan in gaswarm air appliances? T or F2. The ST9120U is a central wiring point for most of

the electrical components in the furnace? T or F3. The ST9120U replaces over 25 Honeywell and

competitor controls? T or F4. The universal electronic fan timer monitors the

thermostat for heat, cool and fan demands? T or F5. The heat and cool on/off delays are set through

dip switches? T or F6. Honeywell only has one resource for crossreference information? T or F


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Answer Key

1. T

2. T3. F4. T5. T

6. F

st9120 fan timer training module

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