Air filter for new heat pump


  #1  
Old 09-16-22, 07:39 AM
J
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Air filter for new heat pump

Hi all,

I'm reaching out for some advice regarding a replacement heat pump I had installed in my home. For various reasons, I'm not confident in my current contractor and am trying to do some homework before deciding how to proceed.

My old unit was a 5-ton Nordyne heat pump which used the standard 1" filter at the bottom of an upflow configuration. I had no reason to believe there was anything inadequate with the sizing of the old unit, the ductwork, or the filter design. I always got what felt like good flow through the supply registers when the unit ran.

I've had the unit replaced with a GE Connect system (a newer inverter system, similar to Gree Flexx and Mr. Cool, for better or worse). The air handler is similar to the old, but a single speed with a variable speed motor, where the old was a two-speed with a variable speed motor.

The new air handler is equipped with a similar 1" filter slot, but came with a metal filter with 1/8" mesh holes (see pictures). It's also an odd size, measuring about 23x20.5". I get good flow with this filter but felt uncomfortable about its ability to protect the equipment from dust and dirt build-up.

I've been searching for a suitable replacement filter, but everything I'm finding seems to restrict flow considerably. I started with a 23x20x1 MERV 8 pleated filter (closest size, but still not readily available), but what I notice is that it gets drawn up hard against the drain pan below the coil and flow to some of the supply registers drops off badly. My suspicion is with the filter getting drawn up like this, I'm effectively reducing it to a 20x20 filter (the approximate size of the drain pan opening below the coil) and reducing the flow. So even with a lower MERV filter, if I can't keep it off the drain pan, I'm not sure if I will be able to keep adequate flow going through the system. The advantage of the metal filter is that it is heavy enough not to get drawn up and the filtration is so low it has very little restriction. In fact, on some of the documentation I've seen, it's advertised and touted as a "washable filter", which I guess it is, but can't imagine it's very protective.

I suspect a 1" filter is just too small for 5 tons (2000 cfm) of flow. Unfortunately, I don't have any easy way to install an external filter in the ductwork. I've included a photo that shows the air handler configuration.

Any suggestions on how to proceed would be appreciated.

Thanks!




 

Last edited by PJmax; 09-16-22 at 10:24 AM. Reason: resized pics
  #2  
Old 09-16-22, 10:28 AM
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That is not a proper filter.
The last picture doesn't show us where the filter goes.

I see a problem. I see an air handler sitting on the floor with no return box.
I need to see where the filter is/goes.

It looks like they used the tall air handler with not enough room for a return box.
Post a picture from further back.
 
  #3  
Old 09-16-22, 11:39 AM
J
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@Pjmax
Will do when I get back home - it's on a return box, and I can show the filter door (typical 1" slot at the bottom of the air handler). Thanks.
 
  #4  
Old 09-16-22, 04:09 PM
J
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