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Thermal Zone
Furnace

Model # GU120M16B Official Thermal Zone gas furnace

Here are the diagrams and repair parts for Official Thermal Zone GU120M16B gas furnace, as well as links to manuals and error code tables, if available.

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Model diagram and schematic

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Showing 10 of 27 parts  |
Capacitor 621435
#7

90+ upflow condensing furnace diagram

Capacitor

Part #621435

Replaced by #12908

?
Manufacturer substitution
This part replaces 621435. Substitute parts can look different from the original.
This item is not returnable
$5.26 | 
16% OFF Phone Price : $6.26
In Stock
Furnace Blower Assembly 902815
#4

90+ upflow condensing furnace diagram

Furnace blower assembly

Part #902815

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

Furnace Vent Limit Switch, 160-degree 626461
#27

90+ upflow condensing furnace diagram

Furnace vent limit switch, 160-degree

Part #626461

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

Orifice 661045
#16

90+ upflow condensing furnace diagram

Orifice

Part #661045

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

Central Air Conditioner Air Handler Drain Pan Connector 663714
#23

90+ upflow condensing furnace diagram

Central air conditioner air handler drain pan connector

Part #663714

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

Furnace Electronic Control Board 903106
#11

90+ upflow condensing furnace diagram

Furnace electronic control board

Part #903106

$297.66
In Stock
Switch 626435
#19

90+ upflow condensing furnace diagram

Switch

Part #626435

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

Gas Valve 624586
#13

90+ upflow condensing furnace diagram

Gas valve

Part #624586

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

Sensor Rod 632316
#15

90+ upflow condensing furnace diagram

Sensor rod

Part #632316

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

Transformer 621486
#3

90+ upflow condensing furnace diagram

Transformer

Part #621486

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

Symptoms for electric water heaters

Why does my water heater's heating element fail often?

Main causes: excessive tank sediment, high voltage supply…

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Why does the temperature of my hot water fluctuate?

Main causes: thermostats need adjustment, bad heating elements, faulty thermostats, tank sediment build-up, broken dip t…

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Repair guides for electric water heaters

How to replace a water heater element

How to replace a water heater element

If your water heater runs out of hot water quickly and one of the two heating elements has failed, replace the element f…

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Repair difficulty
Time required
 30 minutes or less
How to replace an electric water heater thermostat

How to replace an electric water heater thermostat

If the water temperature fluctuates or you don't get enough hot water, follow these instructions to replace your water h…

Read more
Repair difficulty
Time required
 30 minutes or less
How to replace a water heater temperature and pressure (T&P) relief valve

How to replace a water heater temperature and pressure (T&P) relief valve

Replace a broken temperature/pressure (T&P) relief valve on an electric water heater using these instructions.…

Read more
Repair difficulty
Time required
 15 minutes or less

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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

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