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Discussion Starter · #1 ·
While replacing the filter in our horizontal mount attic HVAC unit, I noticed the filter component (a large 4 inch wide filter) is located on the downside of the blower/coils. In other words, the air hits the filter AFTER passing over the coils and right before it goes into the ducts to the house. From what I have been able to find, the filter should be located at the point where the returned air enters the system, to filter out dust, etc. before the air passes through the mechanical parts. Hope this makes sense - I'm not so sure of the correct terms to use. I also read that the filter directional arrows should point in the direction of the air flow (obvious) but also toward the blower. This is impossible with our configuration since the filter is downwind of the blower. We're thinking the unit was installed incorrectly. Anyone know if this is an acceptable configuration or clearly an error?
 

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It should be installed before the coil or the dirt will plug the coil.

The coil can be before the fan on a air handler or electric furnace and must be past the fan on a gas furnace.

Are you 100 % sure you are looking at it properly?

After 5 posts here you can take a pic and add it as a attachment so we can look at it.

Or you can post it on photobucket and put the link here or type in the address.
 

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Discussion Starter · #4 ·
That's what appears to be happening. Facing the unit (it's horizontal), the air flow is from left to right. The filter is at the far right end of the unit. Will try to post a photo.
 

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Take the filter door off and remove the filter and start the unit. You can then tell if it is sucking against the coil by putting a piece of paper against it.

If it blows off then it is going to the right and wrong, if it sucks it to the coil it is correctly installed.

It looks correct to me. Standard air handler with heat strips.
 

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Discussion Starter · #9 ·
Can't tell from the pic. Can you get a wider pic?
That's the best I can do. It's a pretty tight space. The air is definitely flowing in the direction of the arrow with the filter at the far end of the unit. There's nothing to the right of the filter except a box thing with ducts attached (nothing mechanical).
 

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Discussion Starter · #10 ·
Take the filter door off and remove the filter and start the unit. You can then tell if it is sucking against the coil by putting a piece of paper against it.

If it blows off then it is going to the right and wrong, if it sucks it to the coil it is correctly installed.

It looks correct to me. Standard air handler with heat strips.
I took the filter off and stuck my hand in while the air was blowing. It's definitely blowing to the right, in the direction of the arrow.
 

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Sticking your hand in will feel a draft and may confuse you. Use a piece of paper or kleenex and you definitely will see where it is going.

It will suck it hard to the coil if it is going to the left.
 

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Discussion Starter · #12 ·
Sticking your hand in will feel a draft and may confuse you. Use a piece of paper or kleenex and you definitely will see where it is going.

It will suck it hard to the coil if it is going to the left.
Oh my gosh, you are right! Even though it felt like the air was blowing to the right, a kleenex showed it was blowing to the left. Even my husband, who is an avid sailor who knows everything about the wind, was fooled as we were trying to figure this out :) Thank you so much!
 

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Yur Welcome.:wink2:

My Gal is a brilliant nurse and her family are all Doctor's and highly educated. Yet she cannot even figure out what direction or how to change the light bulb in the oven.

We all have our abilities or disabilities. I could not cook a fancy meal to save my life.:biggrin2:
 
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