[ripsaw]

Climate zone: Lower great lakes area (SW Indiana)

Home: Single level ranch 1800 sq ft, crawl space foundation. 8' ceilings except living room is vaulted

Equipment: Amana ACVC960603BNBA two stage variable speed downflow gas furnace, 3 ton Amana ASXC16 A/C Condenser (2 stage Copeland, 2 speed fan), Aspen evaporator coil (cased), Honeywell Prestige IAQ Thermostat and EIM

Equipment location: Furnace in garage


We bought this house this past January, the above listed system was installed a month later in late February. Install follow-up visit for check and tune was April 10th.

Here is the weird thing. The humidity level shown on the thermostat display rises slowly when the air conditioner runs. For instance, if it's showing 54% humidity with the system idle as soon as the air conditioner comes on, the reading begins to rise and by the time the cycle ends the air conditioner shots off it may read 60% or slightly higher.

I've checked equipment status on the display and it runs in stage 1 a while then always advances to stage two for some time before finishing the cycle. Stage 1 is a gentle cold air flow out the registers can barely hear the blower fan, very nice and seems "just right." However, it never remains only in stage 1 for a cooling cycle. It always ramps up to stage 2. Frankly, stage 2 feels like overkill. The blower gets loud and it's too much cold breeze if seated within, say, 6 - 10' of a register.

I'm just an idiot homeowner not a technician, but I've heard that for effective dehumidification you want a slower gentler fan speed like Stage 1, not the more robust Stage 2.

Had a tech from the installing company come out yesterday to have a look. He said being a recent install it probably needed the refrigerant balanced and that is the first thing he would check. He did that and said he put in 9 ounces of refrigerant.

Unfortunately, the same behavior from the system continues. The humidity displayed on the thermostat rises as the system runs and then remains steady or begins to slightly drop after the cooling cycle ends, settling in about 5 - 7% below where it peaked during the cooling cycle. Then the next cycle, same thing.

I wanted to ask about this on here because that seems to be the reverse of what should be happening? Shouldn't the RH begin to decrease as a central air conditioning system runs, not increase?

P.S. When the unit is running, you can hear water trickling from the drain piping from the evaporator coil, as it should.

 

[Bazooka Joe]

https://www.ahridirectory.org/Home/...ad?ReferenceId=sUzbLVC3/aFB9wkj0dGAH3acybugkCvoLg96WSPGLJ2xMx/vQsSi0E52BXX8qjFh

Ask them for something like this to prove they installed a matched system. Briefly looked at AHRI web-site did not see your system being a match, but could be wrong as no number for the Aspen coil given.

There are very detailed instructions on how to set up blower fan speed field refrigerant charge. Believe it's suppose to be at least 60 degree OD temperature and Goodman wants the final adjustment charge in 1st stage cooling for that model.

How did they determine you need a 3 ton unit, did they do a load calculation? You not being the original owner, who knows if prior unit had problems with humidity also.

If they adjusted the field charge once already after it should have been set on start up, sounds like they are guessing, next they will play with blower speed.

Ask them for the start up/commissioning report they are suppose to do. Things like what is the sub-cooling, superheat, static pressure ,temperature rise across the HX of the furnace are all within manufacturer specifications at whatever fan speed was selected. Amprege draws of motors and compressor etc. etc.

Make sure your system got registered as your manufacturer warranty will decrease significantly if never registered.

 

[Bazooka Joe]

https://www.aspenmfg.com/Content_Matrix/Spec_Sheets/CC-SS-050318.pdf

Aspen looks to show they come with a piston metering device, if you want anything near 16 SEER they should install a TXV. Using cased coil upflow/downflow models, something about a adapter kit needs to be installed on downflow models.

 

[teddy bear]

As joey says, setup is critical.
All a/cs are oversized in Spring/Fall/Rainy Days/Evenings. During the heat of hot day, your a/c should maintain <50%RH if setup correctly.
Get a good %RH temp meter on Amazon for <$20. Set along side of the t-stat to confirm readings. Air leakage through the wall can effect the t-stat readings. Confirm the hole in the wall is cauked.
Cooling air without removing moisture will raise the %RH. Water trickling down the drain sounds go.
Better to measure the room temperature/%RH and the closest a/c supply temp/%RH and convert into ^F dew point in the space compare to ^F dew point of the cold supply air. The dew point is the measure moister content. A proper setup a/c should reduce the dew point 5-8^F in one pass. If lower there is a problem with air leakage or a/c setup. The setup is mechanical like refrigerant or air flow. Slow air flow to increase the moisture removal and slow sensible cooling. Show this to your tech, its all things he may not have thought of. You tell us temp/%RH in and out, we will comment on how it is working.
Keep us posted. Always a chance there is nothing wrong.
Regards Teddy Bear

 

[ripsaw]

The way they determined 3 ton for size is the prior unit was a 3 ton. The estimator that sold the job then said 600 sq ft per ton so 1800 sq ft calls for 3 ton. I have no aptitude for this stuff, most of the higher level technical jargon I don't have any clues what it means.

They're a high volume contractor and sell enough Amana/Goodman that they are allowed to have their own badge put in place of the Amana badge.

I pulled the exact model number off the A/C condenser unit at lunch ... Goodman model ASXC160361CC

 

[ripsaw]

Could have my coil brand/mfg mixed up... might be an Alpine in which case it looks to have TXV instead of piston.

Will report back with exact mfg and model # later after home from work and can double check.

The Goodman site via an AHRI ratings PDF shows that the matched coil for the furnace I have (see post 1) is Alpine CA*F3642*6D* + TXV

Hopefully that's what they used.

 

[pecmsg]

The way they determined 3 ton for size is the prior unit was a 3 ton. The estimator that sold the job then said 600 sq ft per ton so 1800 sq ft calls for 3 ton. I have no aptitude for this stuff, most of the higher level technical jargon I don't have any clues what it means.

They're a high volume contractor and sell enough Amana/Goodman that they are allowed to have their own badge put in place of the Amana badge.

I pulled the exact model number off the A/C condenser unit at lunch ... Goodman model ASXC160361CC

There guessing and full of €£it!

 

[BaldLoonie]

Yes, they are full of #$#&^. BTUs per sq ft is totally bogus. Sizing off what's there ASS-U-MEs that the idiot before these idiots sized it right.

They don't sound smart enough to set the blower right so could be still on factory setting of 2000 CFM instead of 1200 or less for your 3 ton.

You have a Goodman coil, not Aspen, if it is a CA*F

 

[Bazooka Joe]

Could have my coil brand/mfg mixed up... might be an Alpine in which case it looks to have TXV instead of piston.

Will report back with exact mfg and model # later after home from work and can double check.

The Goodman web-site shows more than that one coil as an example ( if I did the math right ) that CAUF3642 gives 15.5 SEER, other Amana coils give 16 SEER.

https://www.ahridirectory.org/Home/...ad?ReferenceId=sUzbLVC3/aFB9wkj0dGAH59yJvb/Mp59E7qesbF/Gn/E3n2Nb342/Ouvzc3D9rdg

As mentioned, that number is Goodman not Alpine or Aspen,

Definitely want to register your system as the Amana has the lifetime whole unit OD unit replacement if compressor fails. Believe that applies to the furnace also, new furnace if HX fails to registered original owner. Goodman models do not have that same coverage.

Anyway I'd be curious the AHRI number they gave you ( or ask them ) or at least the model number of the Alpine or Aspen coil.

Lastly there is another coil manufacturer that starts with a "A" also Lennox owned ADP.

Do your own free load cal. http://www.loadcalc.net/

 

[ripsaw]

Okay I checked label on the coil case. It's an Aspen. Model CC36B34175R157. The label reads as follows:

(dotted lines mine)
-----

MODEL CC36B34175R157

REFRIGERANTS

R-410A TXV INSTALLED

DESIGN PRESSURE 500 PSI
-----

2ND sticker:

-----

ENGINEERED FOR USE WITH AMANA EQUIPMENT

-----

 

[Bazooka Joe]

That Aspen model number looks to be a straight 3 ton coil, if the Goodman CAUF3642 + TXV gave 15.5 SEER being a 3-3.5 ton rated coil, the Aspen is probably around 15 SEER? Give or take. personally could not find that system as being a match using AHRI web-site.

Maybe that coil size is one of several problems with moisture removal?

Hope you where not under the impression and paid for a rated 16 SEER system just because the OD unit model says 16 SEER that your getting that automatically, it's the indoor selection that determines SEER, EER.

https://www.aspenmfg.com/Content_Matrix/installation/CA_CC_CE_CM-IO-123105_100617.pdf

Page 7 2B discusses how to set your subcooling once you get your blower set up correctly and hopefully the static pressure is within manufacturer spec. The OD unit Amana install guide also shows what to set the subcooling to.

You may have to have a independent reputable knowledgeable Contractor ( paying them ) to make the adjustments then see what happens.

I'd still be curious as to what the Installing Contractor offers for a AHRI number.

Certainly that coil is engineered to use with Amana equipment but you would like a matching system to start with.

 

[ripsaw]

Welp, I was sold a 16 seer setup by the estimator, so looks like I may have been taken advantage of (?...)

There are two other Amana/Goodman dealers in the area, both smaller operations instead of a big mega like the one that I bought from.

Next week I'll call the installing contractor and request the AHRI number. I'm sure the receptionist will "have someone call" me. Could be an interesting conversation ...

I'd absolutely pay a service call from one of the other two smaller operations that sell these same systems, to get this system configured properly if it's only matter of correcting the wiring of a control board or something. That is unless they tell me to buzz off because I bought from the big mega contractor instead of them.

P.S. Thanks for the link to that AHRI certificate.

 

[Bazooka Joe]

Page two of the install guide says to install the two baffles ( supplied with coil ) for downflow applications and not to exceed 350 CFM per ton.

You got some added info, subcooling target degree, minimum OD temperature to charge, not to exceed a certain CFM, charge in 1st stage, static pressures, blower set up etc. baffles on ID coil, temperature rise across HX is within manufacturer spec. so have whoever comes out follow the install guides, download them and look yourself, ask to have a commissioning report of your system left on the job, then see what happens..

Don't know how it will affect your labor warranty from the Installing Contractor by going with someone else?

 

[ripsaw]

Sounds good, thanks. As far as labor warranty, may be selling this place in a year or two anyhow so not a big concern. I will say this about the install team that put it in. It was an experienced older tech and a young tech in his early 20's. The young tech was very proud when showing me his work. He did the sheet metal work fitting the new unit into position and making the transition ducting or plenums or whatever (I might have the terminology wrong). I will say his caulk lines of the clear silicone sealant were clean and nice and the sheet metal work looked well done. The other guy ran the new refrigerant lines and set the condenser unit up in place and such, I think.

This new Amana equipment replaces a poorly maintained Tappan system which was the new construction install when house was built in 2003. We bought the place late last year and took possession in January.

A note about layout of the system. Conditioned crawl space. No crawl space foundation vents. Instead, there is one supply register consisting of an open duct and one return consisting of a rectangular cut penetration in the OSB sub floor and wall base which feeds into an wall cavity creating a wall cavity "duct" up to a return boot in garage attic. You can shine your flashight in there and look up through wall cavity to the return boot.

I've inspected all return connections in garage attic where they tie to the return plenum and all appear good. Flex duct of course but the zip ties are the big heavy duty type and all well placed and tight. Reason I checked was due to the indoor humidity situation to make sure no garage attic air being pulled into return ducting.

Which brings me back to the conditioned crawl space. Crawl space is dry, with proper vapor barrier over pea gravel, sump pump, etc. The system configuration and tuning tech that came out a month after the new Amana system was installed, suggested I consider blocking off that wall cavity return at the OSB cut. Which I did a while back by simply using sheet of reynolds aluminum foil and some aluminized hvac tape.

Although off-topic from the original theme of this thread, I am on the fence about whether to remove the foil and open the crawl space return back up or not. If I do, I think it prudent to have a UV light system installed on the return where it links to furnace in garage. Any opinions on all that are most welcome.

Our last house had what I consider a better laid out hvac conditioning in the crawl space (no foundation vents in it either), featuring two finished registers and two return openings, with a Honeywell UV system in garage at where main return duct goes to furnace.

 

[Bazooka Joe]

. It was an experienced older tech and a young tech in his early 20's. The young tech was very proud when showing me his work.

Don't automatically judge experience level of someone by their age, some people do a late career change...seen it happen....

 

[pecmsg]

. It was an experienced older tech and a young tech in his early 20's. The young tech was very proud when showing me his work.

Don't automatically judge experience level of someone by their age, some people do a late career change...seen it happen....

and all too many haven't learned from there mistakes!