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Boss
Gas Water Heater

Model # 5-40-NKRT8-42 Official Boss gas water heater

Here are the diagrams and repair parts for Official Boss 5-40-NKRT8-42 gas water heater, 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 26 parts  |
Water Heater Thermocouple 9000283
#14

Replacement parts diagram

Water heater thermocouple

Part #9000283

Replaced by #H06E-36

?
Manufacturer substitution
This part replaces 9000283. Substitute parts can look different from the original.
This item is not returnable
$14.52 | 
12% OFF Phone Price : $16.52
Back Order
Thermostat 9000249
#9

Replacement parts diagram

Thermostat

Part #9000249

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

Water Heater Manifold Inner Door 9000281
#18

Replacement parts diagram

Water heater manifold inner door

Part #9000281

$17.69 | 
10% OFF Phone Price : $19.69
In Stock
Anode Rod 9001314
#6

Replacement parts diagram

Anode rod

Part #9001314

Replaced by #100300397

?
Manufacturer substitution
This part replaces 9001314. Substitute parts can look different from the original.
$55.38 | 
10% OFF Phone Price : $61.38
In Stock
Drain Pan 9000743
#26B

Replacement parts diagram

Drain pan

Part #9000743

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

Annode Rod 9000279
#21

Replacement parts diagram

Annode rod

Part #9000279

Replaced by #100108571

?
Manufacturer substitution
This part replaces 9000279. Substitute parts can look different from the original.
$90.00
In Stock
Water Heater Burner 9000390
#16A

Replacement parts diagram

Water heater burner

Part #9000390

Replaced by #100108399

?
Manufacturer substitution
This part replaces 9000390. Substitute parts can look different from the original.
$27.78
In Stock
Water Heater Pilot Tube Assembly (replaces Std317025, Std317255) 9000278
#13

Replacement parts diagram

Water heater pilot tube assembly (replaces std317025, std317255)

Part #9000278

Replaced by #100108370

?
Manufacturer substitution
This part replaces 9000278. Substitute parts can look different from the original.
$36.67
In Stock
Rexel Pan Base 9001609
#26A

Replacement parts diagram

Rexel pan base

Part #9001609

Replaced by #100108616

?
Manufacturer substitution
This part replaces 9001609. Substitute parts can look different from the original.
$64.44
In Stock
Nipple 9000415
#4

Replacement parts diagram

Nipple

Part #9000415

Replaced by #100108409

?
Manufacturer substitution
This part replaces 9000415. Substitute parts can look different from the original.
$25.71
In Stock

Most common symptoms to help you fix your water heaters

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Why isn't my water heater heating my water?

Main causes: lack of power, no gas supply, thermostat limit switch tripped, bad element, bad thermostat, gas valve failu…

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Why isn't my water heater making the water hot enough?

Main causes: thermostats need adjustment, water heater capacity too low, bad heating element, thermostat failure, excess…

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Why is there water in my water heater's drain pan?

Main causes: loose water pipe fittings, leaky drain valve, bad temperature-pressure relief valve, leaky heating element,…

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Why does my hot water smell like rotten eggs?

Main causes: water supply needs chlorine treatment, anode rod too reactive…

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Why isn't my water heater making enough hot water?

Main causes: broken heating element, thermostat failure, excessive tank sediment, tank size too small, burner valve asse…

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Why is my water heater making the water too hot?

Main causes: thermostat temperature set too high, thermostats need adjustment, faulty thermostat, shorted heating elemen…

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Why is my water heater's pressure relief valve dripping water?

Main causes: faulty pressure relief valve, water is overheating…

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Effective articles & videos to help repair your water heaters

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

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Wiring schematic symbols explained video

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