Steps in cleaning air handler or blower unit for A/C or heat pump or furnace systems:

This article illustrates and describes key steps in removing and cleaning the blower fan assembly in an air handler used for air conditioning or heating.

This article series describes Air Conditioning Blower Fan, Cooling Coil, Fan Coil Unit Leaks, Mold, and Filter Problems &amp Repairs.

Air Handling Blower Fan Cleaning Q&A

These questions and answers about the procedure for cleaning the air handler blower fan assembly were posted originally

at BLOWER FAN ASSEMBLY CLEANING - be sure to check out the detailed cleaning procedures and warnings given on that page.

 

Question: Is my health at risk due to the mold in the air conditioner air handler in these photos?

Hello and thank you. I just found your site and I'd like to know how to donate if possible. However, to my question, if I may:

Can you confirm if it's possible to identify mold by an ordinary photograph? (See attached photos 1 thru 4.) I am renting a home where our AC unit was recently repaired, but before the repair, the contract technician identified mold in the air handler.

(That would be the evaporator coil, foil insulation on walls, blower fan, etc.)

The property management then had another company only clean the evaporator coil, claiming from photos that the remaining visible contamination is not mold and "everything that needed to be cleaned was done."

Please note, I am a senior, disabled Vet with serious health issues, and I'm concerned about any continued health risks caused by contamination, whether mold or otherwise.

Please also note that my wife and I are looking to buy our own home quickly due to this concern with our rental. - Anonymous by private email 2023/04/26

Moderator reply: bits of mold on AC blower blades, insulation, wires vs contaminated blower compartment & ductwork

Thank you for the questions and photos - working on a reply for you may help us help other readers facing similar questions.

Yes, it's often possible to recognize mold or probable-mold from photographs, but keep in mind that from just the photo we have no idea of just what mold genera/species are present and thus can't be confident of the level of hazard based on the mold's identity.

In general, however, large areas of mold are more-likely to be hazardous, and there's rarely just one mold genera/species present if mold contamination is observed. When there is less than 30 square feet of contiguous moldy material, hiring a mold remediation professional is not necessary.

I can see a very dirty air handler blower fan - thick with house dust and possibly a bit of surface mold growth - the property manager may not care, and you may be moving, but you can take satisfaction that they'll be spending probably two or three times as much as necessary for heating or cooling any of their property that uses a very dirty blower like that - mold concern aside.

I see what looks like rather small areas that include a bit of mold - of unknown genera/species in your photos; the total area looks trivial and would not, alone, explain a building-related illness.

You say you're disabled but didn't give specifics. If you are someone with respiratory illness it makes sense to be extra careful about exposure to mold as well as to other airborne irritants, allergens, etc.

But in general, the bits of what might indeed be mold on those wires is simply too small to be, itself, a health concern unless you put your finger into the mold and then into your eye or into an open sore.

General OPINON: Unless *other* conditions in your rental are thought to be making you sick, the conditions in your photos and the air handler would not be a good reason to rush into buying a home - where making a mistake or being too hasty can be more costly. Hire an experienced home inspector, one who works for you, not the realtor, and get a thorough inspection of the property so that you have a sense of priorities of repair.

BLOWER FAN ASSEMBLY CLEANING - above on this page, describes cleaning a dirty / moldy air handler unit thoroughly.

Our photos during cleaning a rather moldy split system air handler unit

SPLIT SYSTEM AC MOLD CONTAMINATION REMOVAL lets you can see what more-substantial mold looks like on the air handler blades.

Watch out: if there have been leaks and mold growth in the ductwork of your present home or if there are larger areas of mold in the air handler's air path (beyond what we could see in the photos) that could be a more-serious and immediate health concern.

 

Can I clean a dirty air handler blower myself?

We have a two story home with an air conditioning system for down stairs and one for up stairs. We are able to cool the upstairs just fine but the down stairs is always hot.

I believe its because we aren't getting enough air blown into the house. I have read a lot and it sounds like the blower might be dirty. Does this sound accurate and can I fix this problem on my own? On 2011-06-12 by Kristy

by (mod) - Dirty A/C Blower Fan recommendation

Kristy:

Indeed I have actually DOUBLED the air output from a blower unit (the indoor air handler) simply by cleaning the blower fan blades. In a typical squirrel cage blower fan assembly, the long narrow blades are cupped to catch and move air as the assembly spins.

Dirt in the unit fills those cups up to nearly flat - the blower will spin just fine but it moves much less air.

If your blower is visibly dirty, cleaning it can make a significant difference in the total air flow coming out of the system.

While it may be possible for you to do SOME vacuum-cleaning of the blower assembly in your air conditioner's air handler, there's also the risk that you bend some blades or accidentally rip off a wire - a safety concern; and I'm doubtful that you can do a thorough job without disassembling the unit - something best left to a trained service technician.

See BLOWER FAN ASSEMBLY CLEANING

 

Is it risky to clean a squirrel cage fan in an air handler?

Hi can you tell me if cleaning the squirrel cage in an older unit is a risk because disassembly can cause the unit to work incorrectly?

And if so should it be left highly dirty or replaced at that point? On 2020-10-01 by Alan

by (mod) - Dis-assembling a blower unit squirrel cage fan for cleaning - clean vs replacement

Alan

Dis-assembling a blower unit squirrel cage fan for cleaning is a widely-used service procedure and cleaning it can make a very significant improvement in air-flow.

The unit is designed to be able to be removed, cleaned, lubricated, and reinstalled.

If disassembly shows that there was a warn-out bearing or a damaged blower fan then in that case the blower assembly needs replacement.

 

Trouble cleaning the squirrel cage blower fan assembly

I have a squirrel cage fan cleaning problem. The fan is in a Mitsubishi, Mr. Slim MSZ-A15NA indoor unit. The squirrel cage fan can not be removed for cleaning due to problems with the installation location.

Twice a year, the fan blades get caked with dirt, reducing airflow.

To clean it, I 1st have to place a large plastic sheet below the unit to catch all the drippings.

I then use Frost King Foaming Cleaner, which I spray directly onto the fan blades, from the bottom of the discharge vent as I manually rotate the fan.

After letting it soak, I then flush the cleaner and dirt out with a pump spray bottle filled with vinegar. I usually have to repeat this messy endeavor 2 or 3 times to remove the majority of the dirt build-up.

While the above procedure gets the job (partially) done enough to restore airflow, I'm trying to find an alternative spray cleaner that would do a better job.

Mitsubishi engineers had no suggestions other than to point out that the build-up comes from pollution within my house.

But other than humidity, there is little else that I know of to cause the build-ups as I also have supplemental filtration - Filtreat Foam covering the air intake ducts on the unit and a pair of German made, VENTA Air Wash units placed on the floor.

My question, other than asking if you know of an alternative spray cleaner that would do a better job, is if you can offer any other better solutions. Thank you for your time.

Karl Baldwin, kbaldwindw@hughes.net 540-743-2062

Reply:

Karl

I think you are using the right cleaner and I agree that it is a lot of work and a mess.

And I agree that even a small amount of debris on the blades of a squirrel cage fan can significantly cut airflow - I've measured CFM rates before and after cleaning.

In my opinion you should not have to clean the fan very often, certainly not annually.

See the detailed procedure

at BLOWER FAN ASSEMBLY CLEANING 

I would look carefully at these sources of crud that can clog a blower fan.

- leaks in the return duct system that pick up crud from somewhere enroute

- missing, improperly fitted and leaky, or poor filtration level at the return air inlet filter

- damaged fiberglass insulation inside the ductwork

- debris generators in the air handler such as a fraying belt on a blower assembly or oil or grease leaks nearby

- leaks into the air handler return plenum or blower compartment

If the problem were an unusual source of particulate debris in your building itself, we ought to be able to see that right on the air filter.

There is a chance that a lab analysis of the air filter contents might point to an unusual particle source.

Use our email at the CONTACT link at page bottom if you want to arrange a pro-bono forensic lab examination of a dust sample from your blower fan blades and/or the filter following the procedure I document at

DUST SAMPLING PROCEDURE 

How to access a pre 1980's HVAC Squirrell and Blower Motor

Been searching the web for info on how to access a pre 1980's HVAC Squirrell and Blower Motor that is enclosed and setting back from the Air Handler, making it difficult to get to. Do I remove portion of interior wall or what?

Sure appreciate your web, so that I may find a solution. Present Unit is 20 yrs old but still working, but hearing faint noise recently. Can you suggest something to a senior, Thanks On 2020-05-20 by Bill Knapek

by (mod) -

Bill

I don't know what brand and model air handler you're working-on so I can but wave arms and speculate.

Often the blower is impossible to work-on while it's inside the air handler;

Some of those models mount the blower on slider-rails so that you can loosen a couple of bolts and slide it out for access.

On other models you unbolt the unit from the cabinet floor and just drag it out.

Senior to senior speaking, that is, don't get ripped on a sharp sheet metal corner.

 

Goodman GDT090-4A counterflow furnace: how do I find, inspect, clean the blower?

I have a goodman gdt090-4a. counter flow. how would i get to the blower to inspect for dirt on blower? i can not find any instuctions on this on-line, please help, thank you - chipmcclain@hotmail.com 11.20/11

Reply: here's how to find and clean the blower fan on your furnace

Chip,

Contact Goodman with the model number and serial number of your heater and you can obtain, probably at no cost, the installation and maintenance manual for your heating system. We give Goodman contact information at

AMANA & GOODMAN HVAC MANUALS & ERROR CODES a

But generally access to the blower on any furnace is usually trivial: remove the access covers to the blower compartment.

With power OFF - so the furnace won't start and cut off your fingers - one can see and clean the blower squirrell cage fan.

Exactly how to do this is

at BLOWER FAN ASSEMBLY CLEANING 

Refrigerant line or coil freeze-up vs air flow vs dirty fan

I recently found your site and the information I've looked at has been informative and thorough.

I'm not sure if this comment is attached to the article I'm referencing, but in case it is not I am referring to Air Handler Blower Unit Cleaning with all the photos of the process done by 3 Zigs.

My situation is an original unit in a house built in December 1998. The unit is a 5-ton, 10 SEER Trane with a gas furnace. The blower assembly was replaced in Aug. 2008. The indoor/outdoor components have had annual maintenance most years.

I am expecting to replace the system in the next 1-2 years but am trying to hold off as long as possible. The refrigerant lines started to freeze up in mid-July due to a low R22 level in the system, which I knew from the year before. It was serviced and 5.5 pounds of R22 added.

Since then it has not been freezing up and keeping the 3-story house comfortable enough if not perfect on the 3rd floor. I'm wondering if the kind of blower unit cleaning you describe would be worth the cost to extend the life of the system.

I live in West Chester, PA, west of Philadelphia. If you think this cleaning would be beneficial, what would be a fair price to pay for it? Thanks for any guidance. On 2019-08-14 by Nathan Huang

by (mod) -

Take a look at the airflow or air output;

Take a look visually at the blower fan itself for the amount of dirt on the squirrel cage fan blades.

As I've noted, you can as much as double the air output if the blower is dirty;

 

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Continue reading at BLOWER FAN ASSEMBLY CLEANING - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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• BLOWER FAN ASSEMBLY CLEANING
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