Fiber_Cement_Siding_Defects.php Reversed Furnace Covers on Carrier = Unsafe
InspectAPedia®   -   Search InspectApedia

Dust and dirt accumulation inside this Carrier furnace where they don't belong, caused by putting the wrong covers in place (C) InspectApedia.com Roger Hankey HankeyandBrown.comReversed Furnace Covers = Unsafe

Reversed furnace covers are rare, improper & potentially dangerous

This article by Roger Hankey discusses the safety and operating problems that can occur when the solid and louvered furnaces are installed in the wrong position or "swapped" on some furnaces such as the Carrier 58WAV Upflow and the Carrier 58ZAV Downflow furnace models.

Page top photo: lots of dust and debris collect on the circuit board and other components of the furnace when the louverd cover is installed on the blower where it doesn't belong. As we explain below, there are several safety and functional problems with improperly-installed furnace covers.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?

Swapped Louvered & Solid Covers on Furnaces

- Roger Hankey, ASHI Certified Inspections

An early June 2016 home inspection included finding a gas forced air furnace with its covers reversed.  The air tight blower cover was on the burner compartment, and the louvered burner compartment cover was on the blower cabinet.

The 24 year old furnace was a Carrier model 58WAV (shown above). Carrier made this model from about 1992 until at least 2000.  I do not recall seeing another furnace with reversed covers prior to this inspection. 

In replacing the covers on this Carrier furnace someone installed them swapped from their proper position.

Above notice that the solid cover has been installed on the upper half of the furnace front. But this is a Carrier 58WAV Upflow Furnace in which the burner is on the upper half of the unit and the blower at the bottom of the unit.

Watch out: Installing the solid cover on the burner compartment starves the burner for combustion air, risking improper and even dangerously unsafe burner operation.

In our photo above you'll also see that the louvered cover was installed on the furnace bottom where it allows unfiltered room air into the blower compartment. The solid cover should have been used here.

Below is a photo of the data tag for this heating furnace, confirming, even without removing the covers, that it's a 58WAV Upflow unit.

Carrier furnace label identifying a 58WAV Upflow furnace unit (C) Roger Hankey at InspectApedia.com & HankeyandBrown.com

The result of the misplaced covers was an extremely dirty system since the blower cabinet was pulling in unfiltered air (photo at the top of this page and photo below). 

Carrier furnace with very dirty blower compartment where louvered rather than solid door was installed (C) Roger Hankey at InspectApedia.com and at HankeyandBrown.com

Our report recommended the system be cleaned and corrected by a qualified HVAC firm. We further stated that the furnace was at the end of its normal service life.

Nine days later, I found another Carrier 58WAV furnace, 21 years old, with the same reversed covers situation - shown below. 

Carrier 58WAV Uplow furnace with covers reversed - on wrong openings - improper & unsafe (C) InspectApedia.com Roger Hankey also HankeyandBrown.com

In this case, the furnace was clean enough to operate briefly.

Watch out: However, a carbon monoxide test in the vent produced results consistent with a heat exchanger defect. (CO levels rising after the blower came on.) 

Below we show the same furnace with the covers replaced in their proper positions.

The louverd cover is on the upper half of this furnace where we find the burner (and where combustion air inlet is required), and the solid cover is on the lower half of the furnace over the blower compartment.

Carrier upflow gas furnace with the two cover doors replaced in their proper position (C) Roger Hankey at InspectApedia.com & HankeyandBrown.com

This furnace is VERY similar to its down-flow twin, model 58ZAV. The image shown below compares both models. Notice the similar size, shape, and cover designs. 

These images suggest that Carrier found it cost effective to make the covers fit either furnace.  There is no marking on either cover to inform the owner or occupant of the proper cover locations. 

Below, from Carrier's documentation for these furnaces we show the interior of the Model 58WAV Upflow Furnace, clearly indicating that the gas burner is in the upper half of the unit and the blower fan compartment at the furnace base or bottom.

Interior of the Carrier 58WAV Upflow gas furnace showing the location of the gas burner vs blower compartments - cited & discussed at InspectApedia.com

Both covers will fit in either location and when installed, both will depress the blower safety switch. 

This model furnace was also offered in the Bryant label and other brands built by Carrier.

People unfamiliar with furnaces or who have only seen down-flow furnaces may not realize the proper cover position on up-flow furnaces, and vice versa. 

While it is easy to correct reversed covers, the consequences of reversed covers include poor air circulation particularly in cooling mode, improper combustion due to insufficient air in the burner compartment, and if the covers have been reversed for an extended time, inefficient heat transfer due to dust coating all the surfaces of the heat exchanger and cooling coil.

Additionally, if an atmospherically vented water heater is alongside the furnace, the unrestricted airflow into the blower has the potential to downdraft the water heater.

Watch out: providing insufficient combustion air to a gas burner risks production of dangerous levels of carbon monoxide, a potentially fatal hazard for building occupants.

While researching this story, I was able to find only one other inspector’s website with an image or discussion of reversed furnace covers.

His example was a Trane furnace.

When encountering any of these very popular furnace models, home inspectors are advised to explain the proper cover location to their customer and/or mark the proper locations on the covers, in addition to recommend cleaning and any other necessary corrections by a qualified heating & cooling contractor.

...

Roger Hankey is the retired principal of Hankey and Brown Inspections formerly of Eden Prairie, MN. Mr. Hankey is a past chairman of the ASHI Standards Committee and served in other ASHI chapter and national leadership roles.

Mr. Hankey was a National Radon Proficiency Program certified measurement professional and is a Level II infrared thermographer and a consultant on cold climate housing and moisture intrusion.  Contact Roger Hankey at: 970-393-6604 - rogerhankey47@gmail.com

Mr. Hankey is a frequent contributor to InspectAPedia.com. See AIR HANDLER DUST CONTAMINATION, and ATTIC INSULATION MISSING and BUILDING INSPECTION SURPRISE PROVES NEED for SCOPE, and CONDENSING GAS FURNACE INSPECTION & TESTS, and CORROSION & MOISTURE SOURCES in PANELS, and HEAT RECOVERY VENTILATOR FIRE, and others.

...


ADVERTISEMENT


...

Continue reading at HEATING FURNACE INSPECTION GUIDE, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

Suggested citation for this web page

HEATING FURNACE COVER SAFETY at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING SYSTEMS

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.

Comment Form is loading comments...

 

IF above you see "Comment Form is loading comments..." then COMMENT BOX - countable.ca / bawkbox.com IS NOT WORKING.

In any case you are welcome to send an email directly to us at InspectApedia.com at editor@inspectApedia.com

We'll reply to you directly. Please help us help you by noting, in your email, the URL of the InspectApedia page where you wanted to comment.

Citations & References

In addition to any citations in the article above, a full list is available on request.


ADVERTISEMENT