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SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA

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SparkChaser

Premium Member

AC questions. Adding filter

I have a SDHV (Small Duct High Velocity) AC system. I'm looking to add (from the AC dealer) a new filter. It's a Lenox Healthy Climate 16 filter. »www.lennox.com/products/ ··· ms/HC16/ The AC company, of course says it's fine but I'm wondering if there is any restricted airflow. The filter says a CADR of 1900. The air handler is a Spacepak ESP-3642D »spacepak.com/brochures-m ··· tion.asp . It has a CFM rating at 1.5"WC of 850.

Is there a way to figure the relationship of those numbers?

SandShark5
Long may you run
Premium Member
join:2000-05-23
Santa Fe, TX

SandShark5

Premium Member

What size and type of return air filter are you presently using?

SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA

SparkChaser

Premium Member

said by SandShark5:

What size and type of return air filter are you presently using?

14X36X1 fiberglass ( i think, at least not pleated)

SandShark5
Long may you run
Premium Member
join:2000-05-23
Santa Fe, TX

SandShark5

Premium Member

Compared to what you have at present, adding the new filter is definitely going to cause more of a pressure drop, all things being equal. In other words, if there aren't going to be any major modifications to the existing supply and return air duct work, adding a 4" Merv 16 filter in place of a 1" fiberglass filter will certainly create more of a pressure drop. How much of a pressure drop and whether your system can handle it, who knows? It depends on what the new filter is rated and what the pressure drop (static pressure) is of your system at present.

mix
join:2002-03-19
Romeo, MI

mix to SparkChaser

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to SparkChaser
Why are you looking to add a MERV 16 filter?

SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA

2 edits

SparkChaser to SandShark5

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to SandShark5
SandShark5 See Profile

Thanks. That's what I thought. Time to call the man and ask if they know what they are doing. The system is 10 yo and has worked well. The company specializes in these SDHV's and it's cobbled together with parts from Spacepak and Unico. The filter would have to be added to the return duct. All of this is in an attic that one should get paid extra to work in.

The main problem we have had is mildew smell in the spring when the unit had been sitting. Yes, I do realize the following is sales talk (at least in part) The tech claims there is dust build up on the coils and a better filter would reduce it. I also suffer from allergies, so better air quality would be welcomed. As for using this particular filter, it's what they recommend. Since everything is sort of handcrafted, I guess they could put anything.

He was also talking about putting UV lamps over the coil in the air handler.

Edit: in looking at the receipt, it says MERV 10 but the tech left me the MERV 16 brochure, time for that call

Just found the specs on the net.


SparkChaser

2 edits

SparkChaser to mix

Premium Member

to mix
said by mix:

Why are you looking to add a MERV 16 filter?

The box installed handles a 10 or a 16 MERV. The only difference is the price of the filter. I have a lot of allergy problems and if this helps, it's worth it.
averagedude
join:2002-01-30
San Diego, CA

averagedude to SandShark5

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In my line of work designing mechanical systems, when ever an owner/architect says the project is going to be LEED or have any type of high efficiency filters I know I am going to have problems.

I have compensate for the added filter pressure drop by (singular or in combination):
a. Increase by 2x the square area of the filter and possibly add merv 8 pre filters.
b. Increase the size of all the ductwork.
c. Add extra HP to the fan motor.

IMO (and possibly a small rant, sorry) For residential systems stop using the heating and air conditioning system to "filter" your air. The system filter is there to keep the coil clean...and the side effect is that it cleans your air. If you want HEPA clean air then get a separate air cleaner for that purpose.

What I typically see is that home owners want cleaner air - totally understandable and a valid request.
They look at a true stand alone HEPA style air cleaner and get sticker shock $150-$300, the extra electricity and cost, and fan noise.
Then they walk down the filter isle and see a "HEPA" filter for their AC system and think....Hmm I could filter the whole house for $25 - $30, I'm brilliant - NOT!

This reminds me of an IHACI.org seminar I went to. He had a whole section dedicated for high efficiency filters and all the trouble they cause when home owners add them when the system was not originally designed for them.

Low air flow can cause all sorts of issues in regards to the refrigerant cycle and gas heating and I will leave those issued to the experts.

I do want to add that I am for UV lights for evap coils as they do not add any pressure drop.

Jack_in_VA
Premium Member
join:2007-11-26
North, VA

Jack_in_VA

Premium Member

I do want to add that I am for UV lights for evap coils as they do not add any pressure drop.

Maybe I missed our misunderstood something. How does a UV Light assy protect the evaporator coil from dirt, dust and other contaminants? I understand bacteria, viruses etc. are killed by the ultraviolet rays but these don't effect the evap coil.

mix
join:2002-03-19
Romeo, MI
GL.iNet GL-B1300
Netgear CM500

mix to SparkChaser

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to SparkChaser
The difference is price and size of particles that get filtered at the expense of airflow. Honestly, you should have paid to have the coil cleaned and replaced the fiber glass filter with a pleated filter (merv 6, 7 or maybe 8) and moved on. The rest is pretty much one big rip off and most of the difference you will notice will be a placebo effect. Also, be prepared that the first time you have some issue with your ac system one of the first things to be suggested as the cause of your problem will be the air filter, and they will want to remove it (irregardless if it is really the cause of your issue or not). Good luck.

SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA

SparkChaser

Premium Member

said by mix:

The difference is price and size of particles that get filtered at the expense of airflow. Honestly, you should have paid to have the coil cleaned and replaced the fiber glass filter with a pleated filter (merv 6, 7 or maybe 8) and moved on.

I did pay to have the coil cleaned. I do every year. I haven't had anything installed yet. That was the reason for the post.

What I am told and I realize the the person suggesting it, is biased, is that the standard pleated filter does not play well with the SDHV system. I don't have numbers on a standard filter to compare. You may be right or wrong but I appreciate your comments. Thanks.

Jack_in_VA
Premium Member
join:2007-11-26
North, VA

Jack_in_VA

Premium Member

said by SparkChaser:

said by mix:

The difference is price and size of particles that get filtered at the expense of airflow. Honestly, you should have paid to have the coil cleaned and replaced the fiber glass filter with a pleated filter (merv 6, 7 or maybe 8) and moved on.

I did pay to have the coil cleaned. I do every year. I haven't had anything installed yet. That was the reason for the post.

What I am told and I realize the the person suggesting it, is biased, is that the standard pleated filter does not play well with the SDHV system. I don't have numbers on a standard filter to compare. You may be right or wrong but I appreciate your comments. Thanks.

Why don't you contact a reputable HVAC company and get their recommendation?

SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA

SparkChaser

Premium Member

said by Jack_in_VA:

Why don't you contact a reputable HVAC company and get their recommendation?

That was it
»www.sila-air.com/
averagedude
join:2002-01-30
San Diego, CA

averagedude to Jack_in_VA

Member

to Jack_in_VA
said by Jack_in_VA:

I do want to add that I am for UV lights for evap coils as they do not add any pressure drop.

Maybe I missed our misunderstood something. How does a UV Light assy protect the evaporator coil from dirt, dust and other contaminants? I understand bacteria, viruses etc. are killed by the ultraviolet rays but these don't effect the evap coil.

I my world everything is about air flow and heat transfer.

Molds, spores, fungus (Egon Spengler), slimes, and biofilms can coat the fins in the evaporator and reduce air flow and heat transfer.

That weird smell when you first turn on your ac for the summer...well that is the condensate (water) mixing with small particles of dust (ie skin cells) making a nice habitat for the molds, spores and fungus to grow. Usually, this isn't an issue.

If the growth gets out of control, the nasty stuff can clog up the air flow and ruining any hope for air transfer - not to mention having an impact on your health. Most of the time this is a non issue and nothing to worry about. Uv lights stop the growth, and in addition have side effect of cleaning your air with out a decrease in fan performance.

»www.steril-aire.com/faq_res.htm

Jack_in_VA
Premium Member
join:2007-11-26
North, VA

Jack_in_VA

Premium Member

I've found that Two cleanings per year takes care of that problem very well. One in the spring and one in the fall after the cooling season. I just replaced my units in which the air handler was 17 years old. The coil and squirrel cage fan looked like new thanks to the appropriate preventative maintenance. The rest of the unit had considerable rust and the wiring was failing but the air path was pristine.

SandShark5
Long may you run
Premium Member
join:2000-05-23
Santa Fe, TX

SandShark5

Premium Member

said by Jack_in_VA:

I've found that Two cleanings per year takes care of that problem very well. One in the spring and one in the fall after the cooling season. I just replaced my units in which the air handler was 17 years old. The coil and squirrel cage fan looked like new thanks to the appropriate preventative maintenance. The rest of the unit had considerable rust and the wiring was failing but the air path was pristine.

I don't know anyone who has their evaporator coil cleaned twice a year. That's very unusual. Didn't you say the old air handler was full of mold? Using UV lights, you could have prevented the mold and not had to pay to have your coil cleaned twice a year.

Jack_in_VA
Premium Member
join:2007-11-26
North, VA

1 edit

Jack_in_VA

Premium Member

said by SandShark5:

said by Jack_in_VA:

I've found that Two cleanings per year takes care of that problem very well. One in the spring and one in the fall after the cooling season. I just replaced my units in which the air handler was 17 years old. The coil and squirrel cage fan looked like new thanks to the appropriate preventative maintenance. The rest of the unit had considerable rust and the wiring was failing but the air path was pristine.

I don't know anyone who has their evaporator coil cleaned twice a year. That's very unusual. Didn't you say the old air handler was full of mold? Using UV lights, you could have prevented the mold and not had to pay to have your coil cleaned twice a year.

My HVAC company sells and installs UV systems but just for those who absolutely insist on installing one.

Having an extensive Maintenance background it's not unusual to do extensive PM. Mold was/is the least of my concerns. Dirt/crud/lint that plugs the coil up is the primary focus. So while it may be unusual to you to me it's perfectly normal.

SandShark5
Long may you run
Premium Member
join:2000-05-23
Santa Fe, TX

SandShark5

Premium Member

Ahh, so the mold was only on the outside of the unit. Those thin pieces of interior cabinet insulation must have been some super-duper insulation, huh, Jack?

As usual, you're right, Jack. Who am I to second-guess someone with such an extensive background in maintaining millions of dollars in equipment! You are the man!

Jack_in_VA
Premium Member
join:2007-11-26
North, VA

Jack_in_VA

Premium Member

The thin insulation on the inside was dirty from the dirt that came through the filters. No visible mold as the the technician apparently treated it in the cleaning procedure. I inspected it as did the installers of the new unit when it was removed before putting it on their truck.