Scorched Air Filter Size

Andyk

I am with a wholesale distributor in Upstate NY. I sold to a very competent contractor ( his workmanship is impeccable) an Air Ease ( Allied Industries ) G1D91BU10016C ,100k BTU 1600cfm warm air furnace with a 4 ton cased a/c coil matched to a 3.5 ton condenser.

The contractor installed the unit with the recommended air filter size ( 20x20 cleanable filter ) that  is supplied with the unit. I have contacted tech svc and they stand by the printed filter size. Somehow we became involved with the homeowner....he insists that the filter size is not correct...he has spoken to a supposed expert etc...it's a long story but we should not have been involved with the homeowner at all, the calls should have been referred to the installing contractor. Well, my question to this forum of mainly contractors is what you would do to resolve this supposed mistake. We referred the homeowner to the ManualD tables as per Air Ease tech service. I am just looking for input on if you agree with the size of the filter etc ? To clarify, the contractor is willing to do what is needed to satisfy the customer as long as it's proven that the size is wrong.



PS: The homeowner is a retired naval nuclear engineer.



Thanks for any wisdom.



Andy

Big Ed_4

Customer

Well to be honest to get you going out the door , you may best just give the Home owner what he wants ... It would be what I would do .. It is better to slow down the air when entering the filter element Lager is better at this point , but atleast s you installed the recommended size ..

John Mills_5

the manual says

Tech manual says 20x20 washable at 1600 CFM, if you use throwaway, use 2 of them. The washable usually are worthless and not restrictive. I'd guess that furnace comes with a slot for a 16x25 beside it. Same principle, 400 sq inches. Too small for 1600 CFM but that's the way people do it constantly. Personally I'd prefer a 16x25 media beside the furnace or a Right Angle Air Bear myself. 

canmar

CFM's

First off, Air filter size all depends on the amount of CFM's you are trying to run your system at and the operating static pressure.  The fact is if the homeowner says its too small and is fighting you, put a bigger filter in and don't waste more of your time and effort on it.  Filter boxes are cheap.  Myself, I am bit of a pain in the **** and want to know why he thinks its too small.  Do you have a simple ductulator you could show him?

steamer7676

fix it up

If the contractor is going to "make it right" then have him put in what the customer wants have the customer sign off on it and be done with it. A slightly larger filter shouldn't hurt anything and seems to be a pretty cheap fix. i have found if a difficult customer gives you an easy out and it makes them  warm and fuzzy then take it as long it doesn't effect the system integrity. i didn't see it in the post but I'm guessing he wants a bigger filter and why does he think it needs to be bigger does he have anything on paper.

STEVE PAUL_3

The customer is not always right

When he tries to re-engineer and re-jigger the manufacturers product and/or procedures. If a contractor gets creative with the manufacturers instructions and supplied parts, he opens up a can of liability worms. Especially if the customer is an engineer, he should be the 1st to recognise this. On the other hand if the contractor wants to keep the customer happy, he can attempt to get written consent and approval from the manufacturer for the changes requested. Absent the manufacturers blessing for those alterations, I don't see how or why a contractor should put his neck on the chopping block for an ill advised request from a customer.  

Ironman

Basic Rule of Thumb...

You need 1sq. inch of filter surface area for every 2cfm. So a 20x20 has 400sq. inches and is good for 800cfm. What the manufacturer puts with the furnace is what the cabinet size allows. Doesn't mean that it's adequate. Usually it's not.



Using a pleated filter greatly increases the surface area within the same frame size due to the pleats. This is the simplest way to get more surface area.

VictoriaEnergy

If I were you...

If I was in your shoes, I'd be thinking of a few things, but mainly how I might best help out MY customer, The Contractor.



The homeowner is raising an issue about the filter size.  Why?  Does he have an issue with velocity noise?  And thinks a less restrictive filter might help?  Or; maybe he has an issue with dust and want better filtering performance?We all know the supplied filters won't stop anything smaller than a house fly.  If the contractor provides his material and labor expense at no charge and the homeowner winds up no better off, everyone looses.



I'd clear it the contractor first, then phone the homeowner; stand correctly behind your contractor as the supplied filter is what the manuf recommend.  Period.  Yes; 6 more experts will offer 7 definitively different opinions...I'd then ask what he hopes to gain with the bigger filter.  If it's a dust issue, you could offer to extend a deal on a bigger and better efficiency filter to the contractor that he'd agree to a reduced rate to install.  If it is a noise issue, you could similarly offer a break on acoustic insulation and some bigger tin, whatever, just work with the contractor.



If the contractor has to install anything for free, I think his impeccable rep winds up tarnished since the homeowner had to make an end run around the contractor to get what he wanted.

If he's a retired sub-mariner/nuke engineer:  It'll be about the noise!

icesailor

Scorched Air Satisfaction:

There are some customers who will never be satisfied with anything. This sounds like one of them. Retired military can be a special PITA. I've met this guy. Or a few just like him. 100% of scorched air furnaces come with a filter like this. That isn't good enough for him. From his description, Retired Navy Nuclear sub engineer, should have been writing his own specs for his pet project.

If you were my supplier and you had been talking with my customer, and the situation was as described, standard supplied filter, I would be quite annoyed with you.  

Nuke boats are no less a POS as any other high tech machine made by man. The reason that service techs that come from the military are so good is because of their experience fixing broken things that were poorly designed and mis-applied.

A sad situation all around. A reputable installer, being blamed for something beyond his control.

Tim_75

Face velocity

The furnace is capable of 1600 CFM, but with a 3.5 T ACCU, should not be set up to run at 1600. In upstate NY, the cooling load will be more heavily latent than sensible and the meticulous contractor would certainly know this, and would have set the system up to run at no more than 1350 CFM.



Filter sized by people that do not use their thumbs to do so would be sized at 400 to 500 fpm face velocity (this is not affected by pleats in the flilter). At 1350 CFM and 400 fpm, the open area of the filter would be 3.375 sq.ft or 25 x 20 in standard filter sizes. At 500 fpm, 20 x 20 is very acceptable.



Reason with the ex engineer with numbers.