Can’t find your part?   Contact us:
+1-309-603-4777
Sears Parts Direct
Tips to find your model number
Orders

  • Keep track of the models you own in your profile

    Sign in or Register to view or add models

Schedule a repair
Aprilaire
Humidifier

Model # 550 Official Aprilaire humidifier

Here are the diagrams and repair parts for Official Aprilaire 550 humidifier, as well as links to manuals and error code tables, if available.

There are a couple of ways to find the part or diagram you need:

  • Click a diagram to see the parts shown on that diagram.
  • In the search box below, enter all or part of the part number or the part’s name.

Not all parts are shown on the diagrams—those parts are labeled NI, for “not illustrated”.

We encourage you to save the model to your profile, so it’s easy to access parts and manuals for your appliance whenever you log in.

For DIY troubleshooting advice and repair guides, visit our repair help section.

Owner’s manual

Model diagram and schematic

SEARCH WITHIN THIS MODEL

?

This is the number corresponding to the part on the diagram / schematic

Search
ALL PARTS
Showing 10 of 24 parts  |
Wick Pad 10
#1

Model 550 diagram

Wick pad

Part #10

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

Transformer 4010
#14

Model 550 diagram

Transformer

Part #4010

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

Panel 4220
#5

Model 550 diagram

Panel

Part #4220

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

Stainer 4004
#10

Model 550 diagram

Stainer

Part #4004

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

Insert 4217
#2

Model 550 diagram

Insert

Part #4217

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

Compression Fitting (6) 4076
#13

Model 550 diagram

Compression fitting (6)

Part #4076

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

Water Tray 4218
#3

Model 550 diagram

Water tray

Part #4218

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

Humidistat 4016
#15

Model 550 diagram

Humidistat

Part #4016

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

Cover 4222
#7

Model 550 diagram

Cover

Part #4222

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

Compression Fitting And Strainer (6) 4003
#11

Model 550 diagram

Compression fitting and strainer (6)

Part #4003

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

Symptoms for gas chainsaws

Choose a symptom to see related chainsaw repairs.

View all

What should I do if my chainsaw leaks gas?

Main causes: cracked fuel lines, leaky carburetor seals, damaged fuel tank cap, cracked fuel tank…

Read more

Why does my chainsaw run roughly?

Main causes: bad gas, engine needs tune up, cracked fuel lines, dirty carburetor…

Read more

Why won't my chainsaw start?

Main causes: stale gasoline, cracked fuel lines, dirty carburetor, damaged spark plug, worn piston rings…

Read more

Repair guides for gas chainsaws

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

View all
How to rebuild a chainsaw carburetor

How to rebuild a chainsaw carburetor

If your chainsaw isn't running well, a dirty carburetor could be the problem. You can take it apart, clean it and rebuil…

Read more
Repair difficulty
Time required
 15 minutes or less
How to replace a chainsaw carburetor

How to replace a chainsaw carburetor

If the engine won't start even though there's fuel in the chainsaw, the carburetor could be the problem. Sometimes, it's…

Read more
Repair difficulty
Time required
 15 minutes or less
How to replace chainsaw fuel lines

How to replace chainsaw fuel lines

The fuel line on a chainsaw becomes brittle over time and can crack. Replacing it doesn't require a lot of DYI experienc…

Read more
Repair difficulty
Time required
 15 minutes or less

Articles and videos for gas chainsaws

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

View all
How to enjoy all the online benefits we offer on our Sears PartsDirect website

How to enjoy all the online benefits we offer on our Sears PartsDirect website

Learn about all the convenient features on our Sears PartsDirect website that make your parts purchases easier.…

Read more
Top questions about Sears and Sears PartsDirect

Top questions about Sears and Sears PartsDirect

Get answers to frequently asked questions about Sears and Sears PartsDirect.…

Read more
Chainsaw care and troubleshooting tips

Chainsaw care and troubleshooting tips

Learn the basics of taking care of your chainsaw and solving common problems.…

Read more

Parts & More