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Goodman
Furnace

Model # GUN125-5B Official Goodman gas furnace

Here are the diagrams and repair parts for Official Goodman GUN125-5B gas furnace, as well as links to manuals and error code tables, if available.

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Error Codes

Model diagram and schematic

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ALL PARTS
Showing 10 of 115 parts  |
Transformer B11416-00
#1

Misc. electrical/hardware diagram

Transformer

Part #B11416-00

The manufacturer no longer makes this part, and there's no substitute part

Capacitor 10 B9456-52
#1A

Blower assembly diagram

Capacitor 10

Part #B9456-52

Replaced by #12908

?
Manufacturer substitution
This part replaces B9456-52. Substitute parts can look different from the original.
This item is not returnable
$5.26 | 
16% OFF Phone Price : $6.26
In Stock
Capacitor 5/ B9456-50
#10

Misc. electrical/hardware diagram

Capacitor 5/

Part #B9456-50

Replaced by #12005

?
Manufacturer substitution
This part replaces B9456-50. Substitute parts can look different from the original.
$16.49 | 
11% OFF Phone Price : $18.49
In Stock
Motor B13400-12
#2

Blower assembly diagram

Motor

Part #B13400-12

Replaced by #B13400-21S

?
Manufacturer substitution
This part replaces B13400-12. Substitute parts can look different from the original.
$333.82
In Stock
Gas Valve 12826-06S
#1

Gas train diagram

Gas valve

Part #12826-06S

The manufacturer no longer makes this part, and there's no substitute part

Ignition Mod B13707-24
#3

Gas train diagram

Ignition mod

Part #B13707-24

Replaced by #BG1600M51EF-1AA

?
Manufacturer substitution
This part replaces B13707-24. Substitute parts can look different from the original.
$191.94 | 
6% OFF Phone Price : $203.94
In Stock
Blower Wheel B13680-16
#3

Blower assembly diagram

Blower wheel

Part #B13680-16

Replaced by #B1368016S

?
Manufacturer substitution
This part replaces B13680-16. Substitute parts can look different from the original.
$107.24
In Stock
Blower Shell 18393-00
#7B

Blower assembly diagram

Blower shell

Part #18393-00

Replaced by #0271A00016S

?
Manufacturer substitution
This part replaces 18393-00. Substitute parts can look different from the original.
$120.53 | 
9% OFF Phone Price : $132.53
In Stock
Furnace Inducer Vent Motor Assembly B1859001S
#9

Misc. electrical/hardware diagram

Furnace inducer vent motor assembly

Part #B1859001S

$1126.40
In Stock
Heat Exchange 18212-31S
#4C

Heat exchanger assembly diagram

Heat exchange

Part #18212-31S

Replaced by #0257F00067

?
Manufacturer substitution
This part replaces 18212-31S. Substitute parts can look different from the original.
$1620.55
In Stock

Symptoms for water softeners

Choose a symptom to see related water softener repairs.

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Why does my water softener overflow?

Main causes: faulty brine valve assembly, bad rotor valve…

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Why is my softened water salty?

Main causes: clogged drain hose, faulty rotor valve, leaky rotor valve seals…

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Why isn't my water softener using salt?

Main causes: salt bridge inside the salt tank, bad timer, valve motor failure, faulty rotor valve, clogged venturi…

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Why does my water softener leak water?

Main causes: loose water line connections, cracked water-carrying components, bad rotor valve seals…

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Why is there no display on my water softener?

Main causes: lack of electrical power, bad power transformer, faulty timer…

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Why isn't my water softener softening my water?

Main causes: empty salt tank, salt bridge, depleted resin, clogged or damaged venturi, broken rotor position switch, fai…

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Why are water softener resin beads in my water?

Main causes: broken resin tank screen, bad resin tank seals, cracked upper distributor in resin tank…

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Why isn't my water softener meter working?

Main causes: broken water flow meter, faulty timer, water flow to softener is bypassed…

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Repair guides for water softeners

These step-by-step repair guides will help you safely fix what’s broken on your water softener.

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How to replace a water softener venturi

How to replace a water softener venturi

The venturi valve in your water softener draws brine water from the salt tank to the resin tank for regeneration. Follow…

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Repair difficulty
Time required
 15 minutes or less
How to replace a water softener rotor position switch

How to replace a water softener rotor position switch

The rotor position switch detects the position of the valve rotor. If the rotor position switch fails, follow these step…

Read more
Repair difficulty
Time required
 30 minutes or less
How to replace a water softener timer

How to replace a water softener timer

The timer is the control board you use to program the water softener. If the timer isn’t accepting commands when you pus…

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Repair difficulty
Time required
 15 minutes or less

Effective articles & videos to help repair your furnaces

Use the advice and tips in these articles and videos to get the most out of your water softener.

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How to get your furnace ready for winter

Get expert tips for preparing your furnace for winter. Follow maintenance tips to keep your furnace in top shape.…

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Introducing new technical repair content that we’re developing for the Sears Technical Institute

Introducing new technical repair content that we’re developing for the Sears Technical Institute

Learn about Sears Technical Institute and the advanced technical content being developed for aspiring appliance techs.…

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Top questions about Sears and Sears PartsDirect

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