Here's another one to watch for, homeowners & techs!
3M Filtrete 16x25x4 media, to replace Honeywell F100 media
Furnace suddenly cycling on limit. Tech read 192° at the limit. Found that the static pressure drop over the new filter was .55" WC. Taking filter out dropped temp at limit to 134°. Static on the genuine Honeywell media was 1/2 that and the furnace didn't overheat.
We had 3 service calls yesterday related to crappy filters. I did one, the husband offered my $20 to tell his wife it wasn't the filter......LOL
I declined, told him he needed to buy something else though!
Last edited by HeyBob; 02-27-2008 at 04:53 PM.
Reason: can't spell
Home Depot changed from selling the Indiglo brand of 20x25x4 filters, which average about 50% more airflow resistance than the Honeywell media, to selling the 3M ones, which are even more restrictive.
I have had service calls related to them, and expect to be pulling many more of them out of systems this spring during PMs.
They say 20x25x4, but they are actually thicker than 4" to fit in the Honeywell and Air Bear filter housings.
I have had similar experiences, but usually it is the wife asking me if I can say it was something other than her choice of filters that caused a problem.
Originally Posted by HeyBob
3M may take the Oscar for killing more compressors than Paul Harvey did with electrostatic filters!
Been tellen'em for years not to use the 'pleated' filters, too much restriction. Now going to be replacing furnaces because of them.
Now in all fairness, the filter is a good filter but it's marketed as a direct replacement for an OEM filter which is where the problem is. If the contractor who designed the ductwork knew what he was up against, he would have built the duct system accordingly and ultimately sized the filter properly.
It's not the filter's fault per sey, it's the schmuck who stuck it in the rack's fault and the "expert" at the store who said "This is the best filter for your money" when he didnt have any idea what he was talking about or what the application was.
I believe somewhere on the raper it says (some system efficiency may be sacrificed). This has been an ongoing problem and will continue.
Be safe not fast. body parts don't grow back
O.K., so as an average homeowner, I'm stuck behind a rock and a hard place. It's either the POS fiberglass jobs (now, they seem to be half a filter), or the MERV 8 pleated jobs.
Originally Posted by Moose
Been trying to find info on the web re: pressure drop, but it seems to be lacking.
What would you recommend in a 1" filter?
I agree with Ampulmans comments. Several weeks ago, everyone was beating the fiberglass filters stating that they let too much dirt through. Now were being told that these pleated filters are too restrictive. What gives?
No more than 2 cfm per square inch to keep the velocity down so the filter has half a chance. Idealy .75 sq in per cfm.
Originally Posted by ampulman
A prime example of retail consumer products brought to market with the driving force being consumer demand instead of good solid research and concern for what harm the product will do. And the lawyers and bean counters going "No problem, we'll just purchase a large liability insurnace policy on the item and add that to the cost."
Consumers beware....... if the filter that you're buying at the store isn't the same filter as the first one that the contractor installed when he put in your HVAC equipment you might be damaging your equipment or worse voiding the manufacturers warranty.
If you feel the need to use extremely efficient air filters than realize that with few exceptions modifications will need to be made to your ductwork to maintain acceptable and safe air flow through the system. Just because it fits in the spot doesn't mean it belongs there.
Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.
There is no contridiction here the system just can't be adversely effected by the better filter if it is then system performance takes priority over increased filtration.
Originally Posted by jeepgrady