A coil/Condensor sizing

[fyrmnk]

Below is a reply from an HVAC tech web forum on the subject at hand:

"That's not a real mismatch. In the Houston, TX area they successfully undersize coils to remove more of the humidity.

First, you need to be sure the blower is set properly for the necessary cooling air flow. A 4 ton condenser unit should have ~1600 cfm of air flow. Next be sure the filters are clean and all supply registers and returns are open. Lastly, you need to visibly inspect the evaporator coil to be sure it's clean. Until you know you have the proper load (air flow) on the evaporator coil, there's no point in doing anything else.

Once you know the air flow and coil load are correct, then check the charge. If the previous owner didn't have a freeze problem, you shouldn't now. Last way to stop the freezing if all else fails is remove the piston/orifice metering device at the coil and use a thermostatic expansion valve."

[Brian G]

Originally posted by kurt

You're assuming that the judge respects things like contracts, state licensing standards of practice, or anything else.

Well yeah, I am sort of assuming that state law would count for a lot in a state court, but your point is valid. Unless one cares to appeal and pay the heavy price, a bad ruling that flies in the face of state law is just as binding as any other.

I was just somewhat taken aback by the part about "We could not defend the home inspector". That sounds like his actions (or lack thereof) were indefensible. The judge may ignore it, but he had a very valid defense if the standards were in place.

Brian G.

Shakespeare Had a Good Idea Once.... [xx(]

[Brian G]

Originally posted by fyrmnk

It was an International Comfort Products (isn't that Goodman as well?) AC and a Goodman furnace.

I'm pretty sure that's Heil, not Goodman.

Brian G.

Heil Goodman! []

[Scottpat]

"That's not a real mismatch. In the Houston, TX area they successfully undersize coils to remove more of the humidity.

I can see this as the system will run longer, but I still don't agree with undersizing a coil unless the manufacturer says its OK.

Brian G, this case was back in 2000. It was before our license law. But this judge was a work of art.

This house was like a rain forest. I swear that I saw a thunderstorm one day in the house! Mold was on just about every surface and even covered the studs in about half of the home. Wood flooring was warped, it was just a mess.

[mgbinspect]

Not a Shakespeare fan, eh? (Me either) Borrring...

However, what Polonius said is probably one of the most challenging and beneficial persuits of our lives and careers. The entire world is the beneficiary. "This above all: to thine own self be true, And it must follow, as night the day, Thou canst not be false to any man." - Polonius (Hamlet) Letting your conscience be your guide ain't as easy as it sounds and can be humbling and costly at times... [:-magnify accepting that we must "trust, but verify" is a drag. As far as these ideals go on HI boards, TIJ proves to be king of the hill.

Hey, just for future reference, are there any licensed/certified HVAC Techs (past or present) that are members and regular contributors to TIJ?

[hausdok]

Originally posted by mgbinspect

Hey, just for future reference, are there any licensed/certified HVAC Techs (past or present) that are members and regular contributors to TIJ?

Is there any such thing as a licensed and certified HVAC tech? I don't think they need any licensed or certifications to work out here?

OT - OF!!!

M.

[mgbinspect]

Really? I thought you must be certified to handle refrigerant? I did not realize that graduation from a trade school is not required. That's sobering.

Well, then anyone that was in the HVAC trade or owned their own company and is intimately familiar with HVAC systems and considers them self to be a seasoned expert and technician.

How's that. [:-magnify

[Brian G]

Originally posted by mgbinspect

Not a Shakespeare fan, eh? (Me either) Borrring...

He's okay as long as I don't have to try reading the stuff. That old English is dang near a foriegn language at this point.

Forsooth, whence he hath goeth in tway, thence shalt he WHAT THE HELL IS HE TALKING ABOUT? [:-boggled[]

Shakespeare Had a Good Idea Once....

I was thinking of his line about killing all of the lawyers...seems like a sound idea at times. [:-mischie

Brian G.

I Prefer John Grisham [^]

[mgbinspect]

Well, don't get me started on lawyers.. [:-taped][:-dev3] I'm all for tying their tails together and hanging them over the clothes line.

[DonTx]

Some of the really good HVAC companies here do undersize the coil successfully to remove humidity. But very few! The entire system has to be installed properly and there aren't that many companies that will go to the trouble of doing it.

About 2 years ago at a home show, I specifically asked one of these companies whether or not undersizing the coil would void the manufacturers warranty. He said not with the manufacturers he used (I believe it was Rheem/Ruud and Lennox). This same company also manufactured their own evaporator coils to their own specifications. Pretty intense systems if you ever saw one.

However, when I do see mismatched equipment in a Spec home installed by one of the same ole companies I see doing it wrong all the time, I figure it's a goof up on their part and write it up.

I mean geez, if you can't run the ducts properly, seal duct joints and the refrigerant lines at the evaporator coil housing, run the flex gas line through the furnace cabinet, not seal air leaks at the edges of the evaporator coil housing and have air leaks at the furnace/air handler connection, how in the world am I to believe they intentially undersized the evap coil and did it right?

[fyrmnk]

Here's the info off what's installed. Any feedback on this installation?

Furnace by International Comfort Products

Evaporator Coil

model no. EPA42F19B1

mfg. no. NEPD42F19B1

serial no. L984436333

Forced Air Furnace

model no. GNE100F14A1

mfg. no. GNE100F14A1

serial no. L984122059

Air Conditioner by Goodman Manufacturing

model no. CKT481AB

serial no. 9904473052

Thanks again

[BADAIR]

fyrmnk

i had the same thing happen on 2 jobs last year only difference is both were noted in my reports. it is not uncommon for the evaps to be 1/2 to 1 T less than condensers around these parts.

r.e. agent stepped in with his broker and told the warranty service they would discontinue sending new clients. response was we made a mistake in both policy reviews and will replace the units for our normal $50.00 sevice fee.

these vendors are no different than insurance companies that deny claims until someone grows balls, disputes denials, stands up to them, or contacts someone higher up the food chain. when dealing with bottom feeders start at the top and work your way down. the bad taste doesn't last near as long.

i'd contact the components manufacture to get their spin on this specific set up before i would cave.

[Terence McCann]

Nothing good comes from undersizing the evaporators. It's bad engineering pratice.

[fyrmnk]

I heard also that it may be a 3 1/4 ton coil, 3 1/2 ton drive on the furnace, and 4 ton condensor if that makes a difference.

Heard from another HVAC tech today that they also do install smaller A coils here at times, and they adjust orifice sizes for that.

Any other input on this or the info from the spec plates above? Haven't had much luck tracking down a number to contact the manufacturers.

[Scottpat]

Furnace by International Comfort Products

Evaporator Coil

model no. EPA42F19B1

mfg. no. NEPD42F19B1

serial no. L984436333

3.5 Ton coil

Forced Air Furnace

model no. GNE100F14A1

mfg. no. GNE100F14A1

serial no. L984122059

Not relevant to the A/C

Air Conditioner by Goodman Manufacturing

model no. CKT481AB

serial no. 9904473052

I'm assuming that this is the condenser. If so This is a 13 SEER unit, but it is not matched with the proper evap coil.

I would call this a mismatched system.

This is a list of the coils that are matched to this unit for a 13SEER system.

U49/UC49/H49F+EEP

A48-XX

A49-XX

HB60/U60/UC60/H60F+EEP

AE48-XX

U62/UC62+EEP

HB61/U61/UC61/H61F+EEP

[newguy]

Hey guys, HVAC is a huge trade encompassing heating air conditioning and ventilation put an R on the end and you have refrigeration. It is usually broken down into separate trades, tin bashers install the duct work and furnace. Gas pipers is a separate trade again and so is air conditioning. To SERVICE all the above is where you get a technician who is usually an apprentice refrigeration or journeyman. It is not like your regular trades, ie plumber, carpenter, bricklayer, its H V AC R.

The problems you guys have been disgussing here about mismatching coils is simple, it is bad practice, but it is done and the indoor coil (in case we are talking heat pumps as well) should only be one size larger, not smaller. Pipe sizing is set for refrigerant velocity to ensure proper oil return to the compressor. The problems generally show up on retrofit systems where you get salesmen sizing things up improperly and putting in that oversized or under sized coil, a new apprentice with little experience installing it. Then it doesn't work, the warranty expires, a tech comes in and discovers all the screw ups.

I am just wondering why you guys are busting a nut over this? The standards state clearly that we don't do capacity or adequacy or efficiency or any engineering. Seems to me if we guys were to stick to our own standards of observe describe and report, we would have less to worry about.

I have spent 30 years in HVAC Canada and I've seen it all and all I do is write down the model and serial numbers and don't worry about the rest, if I have any questions about the system I defer it to the "EXPERTS" and let them figure it out.

[hausdok]

Well,

The reason that they're 'busting a nut' is that the originator of the thread is in a pickle over a mismatched system and he asked whether it was normal to compare them or not.

Most of us agree that it is not, but that's still not helping his case. In the meantime, it never hurts to discuss the technical aspects of this type of thing if it will help everyone understand these things better and become better at what they do.

ONE TEAM - ONE FIGHT!!!

Mike

[fyrmnk]

And I do appreciate all the responses because I always do like to broaden my knowledge.

It is interesting on how many responses for and against under-sizing the A-coil, not only on HI forums but and HVAC forum as well. Like I mentioned, one local HVAC contractor here even stated on the phone that they also sometimes under size it, but they do other changes as well to make it acceptable.

I agree, this all falls under the "engineering" of the system, but I'm trying to help out my client as much as possible. Thanks again to all for the great feedback as usual.

[Jim Katen]

Originally posted by fyrmnk

It is interesting on how many responses for and against under-sizing the A-coil, not only on HI forums but and HVAC forum as well. Like I mentioned, one local HVAC contractor here even stated on the phone that they also sometimes under size it, but they do other changes as well to make it acceptable.

That is interesting, but consider this. The companies that manufacture this stuff -- Carrier, Rheem, Trane, etc. -- spend lots of money on designing their systems. They have all these guys with letters after their names doing the work. These guys have calculators, computer programs and pocket protectors. They work very hard to ensure that their systems work well because they're trying to beat the pants off of their competitors.

Now consider the installer who decides to ignore the manufacturer's recommended match-ups because, well, someone told him 30 years ago that if you oversize (or undersize) the indoor coil, it'll remove humidity better. That might be true, but it might also screw up the efficiencies that the guys with pocket protectors worked so hard to achieve.

I agree, this all falls under the "engineering" of the system, but I'm trying to help out my client as much as possible. Thanks again to all for the great feedback as usual.

I don't believe it's possible for a home inspector to tell if the coils are properly matched unless he has some pretty specific knowledge. What would be wrong with, when you find coils with seemingly incompatible tonnage numbers, advising your client to call the manufacturer and confirm that they're compatible? What would be the downside to that?

- Jim Katen, Oregon

[newguy]

OK I agree lets help this guy, first off why doesn't he know the S.O.P.? Who is he associated with ASHI, NACHI...? You don't know your own standards you deserve what you get, maybe he should INSTALL HVAC systems instead. But its inspectors who don't know the standards that will give us all a bad name.

Having said that, was the indoor coil model and serial number "READILY ACCESSIBLE", 99% are not, they are inside the plenum on the evap coil. Given all the info I've read so far this inspector is not liable.

[Scottpat]

OK I agree lets help this guy, first off why doesn't he know the S.O.P.? Who is he associated with ASHI, NACHI...? You don't know your own standards you deserve what you get, maybe he should INSTALL HVAC systems instead.

Well for starters, inspecting standards do not provide the knowledge one needs to perform home inspections. We have many fine inspectors in the profession who are not affiliated with any organization. Some use their own Standards, combinations of other standards and some use those of the major HI organizations. Keep in mind that Standards are also the minimal, just like building codes.

But its inspectors who don't know the standards that will give us all a bad name.

No, it's the inspectors who do not report what they are seeing or issue soft reports to not upset the apple cart! Standards might not cover the size of an HVAC unit, but if it is blatantly over or undersized we all have a professional duty to report on it. Irregardless of what the standards say.

Professional negligence can not be denied in any court.

[hausdok]

Hi newguy,

Do you have a name? We prefer to address each other by first names here, so it would be great if you could give us something to call you besides a handle.

I don't want to turn this thread into a debate about good inspectors vs. bad inspectors or SOP's vs. independents without SOP's, but I'd like to interject something here.

This is foreign territory to me because I see about one, maybe two, air conditioners or heat pumps a year (Saw my first heat pump of 2006 the day before yesterday - No data plate on the evaporator cabinet by the way), so any discussion about A/C systems or heat pumps helps me to get smarter about these systems.

This type of discussion about air conditioners - sizing, tonnage, condensate pans, air gaps, fan speed, and all manner of defects - is very common on the member sites of the major organizations. I've seen extremely experienced inspectors on those sites who've been in business 10+ years occasionally come on, explain that they've encountered the intransigent customer syndrome - where the customer never bothered to read the P.I.A. and then turned around and demanded payment from the inspector and sued regardless of the P.I.A.. In those circumstances, it's helpful for them to talk through the issues with the folks on the boards - sort of like meeting for lunch to talk with a bunch of like-minded folks, or milling around at a chapter meeting during the break.

Can you think of a better sounding board for home inspectors than TIJ?

Like Scott said, the standard is the minimum but you have to do what is the standard of care is for your area.

In my area, with our limited exposure to AC systems, inspectors won't be considering half of the things that someone like, say, Norm Sage or Mark Cramer will be considering in Florida or Chris Prickett or Scott Warga will be considering in Phoenix or Anthem, AZ.

Around here, and probably where you are too, fail to understand and report properly on crawlspace and ventilation issues will very quickly bite you in the assets. I should think that down in Florida where Mark is that paying attention to tonnage might be common.

Kansas, being dead center in the middle of the country? Hell, I dunno, but I think one has to be careful not to judge others or their experience or customary practices too quickly on these forums or you end up wiping egg off your face. We like to keep things less judgmental around here and simply proffer the help when we can, because there's always going to be someone reading it that will be helped by it.

ONE TEAM - ONE FIGHT!!!

Mike

[newguy]

My apologies to everyone, I did not mean to insult any one. This discussion seemed to go down hill since I entered it. I did not mean to direct it that way. Like my name says I am a new guy at this and have very little experience at home inspections. I just don't understand why the inspector would be held responsible for the A/C system under these curcunstances, the size difference is in acceptable parameters, he couldn't operate it due to temperature, the standards back him up in more than one definition and the warranty technician is blaming the inspector for his company's mistake. If I read it correctly.

As far as my name goes It is Gordon Kay and I messed up my first subscription some how and ended up using a handle. I will correct that soon.

[fyrmnk]

Is there a chart somewhere that has different codes companies use to indicate tonnage on the spec plates?

Also, does the AHJ look at AC installations when they sign off on furnace installations? Just curious on that since this installation was approved by the city inspector.

Thanks again for all the help.

[fyrmnk]

Originally posted by Terence McCann

Hi Kevin:

Have a look here: http://www.prestonguide.com/

Thanks Terence. Are there general rule of thumbs for determining tonnage without having to look each plate up in a book every time, or is that the only way?

Thanks again.