Need some advice. Never been really impressed with my newer AC unit

[Stainless169]

So I purchased an American Standard 3.5 ton 16 seer ac/gas package unit about three years ago if I remember correctly. This is a variable speed unit and only supposed to run on high when demand requires it. I was able to get a better deal since I bought it and had it installed in the off-season. It was replacing an older unit that came with the house which was probably 20 years old.

During the installation of this unit, there were several red flags. They came and installed it on a rainy day. I didn't think this was a great idea because of the wet surfaces that were going to have to have silicone. I went and checked it the next day to see how the sealing worked and could feel several spots where cold air was coming through. I spoke with the company and they sent out another guy and he applied sealant all over it. He told me that they use that sealant in larger industrial settings. One of the tec's had to go into my attic to run the new cable to the thermostat since this one was more sophisticated than my old one. I noticed later when I was in the attic for another reason, the guy didn't even take the time to rake the insulation back over the entire length that he scraped it out of the way. It took me probably 20 seconds to do this.

I've always felt like this unit does just enough to cool the house. We typically keep it at 73 degrees but in all reality, I don't think we could make it cooler than this during the day. It warms up late in the day to 75, which is understandable.

I've been doing some research and see where I should get between 15-20 degrees difference between the return and the floor vent. I have checked multiple returns and multiple floor vents and they are very close to the same.
74.8 Return
63.2 Out
That is only a difference of 11.6* on a unit that is less than three years old. I am not too impressed at the moment. I feel like I may have blew all of my saving over the last three years on a shotty install. I just noticed that the sealant tape was hanging off the bottom so I pulled it out. I can feel cold air coming out of the corner but the fact that I can feel cold air makes me wonder something else. I seem to recall that there were flexible ducts that hooked to this unit when they had it pulled out. If the ducts were connected properly, I shouldn't be feeling any cold air, correct? I am thinking this cover is just to protect the flexible ductwork.

I am planning to call the company that installed this tomorrow but I'm not sure what good it will do at this point. I held off leaving bad reviews for them after the fact because I didn't want to be petty with the things that I observed and noticed during and after the installation. I would like to pull this unit away from the wall and look myself at what's going on in there but I don't want to get in too far over my head. I'm just not impressed right now.

I live in a 1981 1600 sqft house that is insullated pretty well. The house is not drafty. I figured a 3.5 ton would have frozen us out if wanted. The fact that I'm not seeing an expected difference across the vent and return makes me think that It may not be working correctly. What are the odds that this new unit didn't have the right amount of freon put in it? Is this done at the factory or do the tecs do it when they install?

Attaching pics on the reply post.

 

[Stainless169]

Pics

 

[Stainless169]

Long post, just want to summarize my questions.
1. Shouldn't I expect to see a higher difference than 11.6? I get good air flow.
2. Should I be able to feel cold, drafty, air where it goes into the house if the duct work inside this cover is attached properly?
3. Should I contact the company I bought this from and vent to them or am I wasting my time?
4. Is the freon filled at factory or by installation crew?

 

[Jim greengo]

3 1/2 tons is a lot of cooling for 1600 feet,is that including the basement?

 

[Stainless169]

Good point. That 3.5 above is incorrect now that I think about it. I was looking on my receipt and it said 3.5, but on the install form, it says 3. I honestly can't remember. Trying to decipher it from the tag on the unit.

No basement.

 

[Jim greengo]

3t sounds better,I'd have them come back to check things out.
Do you have returns in all of the rooms?

 

[Stainless169]

3t sounds better,I'd have them come back to check things out.
Do you have returns in all of the rooms?

I have a hallway that splits into two bedrooms. The hallway has a return, both bedrooms share that same return within the room, and there is one in the living room that also splits with the other end of the hallway.

 

[danski0224]

You shouldn't feel any air- it means that there is a duct leak of some sort.

Equipment like this comes pre-charged from the factory. Being off from the start is possible, but not typical. A problem could have developed since then.

It is more likely that the unit is short cycling supply/return air or is drawing in a substantial amount of outside air instead of building return.

It is also possible that something was damaged/disconnected inside the house (flex duct problems) during the installation, or the duct has deteriorated over time and failed.

That type of doghouse (ductwork covering) is a crappy design and it just directs water towards the structure. I do not see any counterflashing on the house. It would be much better if it was straight across from the unit to the house, with a 2" lip up on either side. Nothing on the bottom, either.

There is very little room between the house and the equipment in addition to the apparent elevation change. It is hard to imagine that here ISN'T a problem/defect in getting the ductwork connected and sealed.

 

[66cj225]

Find out if you're making the cold air first, drawing the necessary amps at rated voltage at the condensing unit. Check the discharge air temp just after the air handler coil. If it's cold there and not at the duct discharges, then it's being diluted in between.

 

[Terry D]

When you take your supply and return air difference temps, this is called your delta T. You need to take the readings right at the unit, not at the registers. You need to drill a small hole in your supply plenum and your return at the unit for your temp probe. Then just screw in a couple of sheet metal screws when you are done.

 

[jeepxj]

1981 insulated pretty well?

 

[BD1]

What is discharge temperature at closest duct outlet ?


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[Stainless169]

What is discharge temperature at closest duct outlet ?


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I just checked again this evening. The unit is just outside his room. You can see his window in one of the pics again. I'm not sure how the duct routing is under the slab, but that is the closest.
The hallway outside his room:75
The temp coming out of his floor:62.6
12.4 difference.

 

[Stainless169]

1981 insulated pretty well?

I grew up in a house from the 40's without insulation it seemed. So my opinion may be skewed lol. I was just implying, the house is sealed pretty well considering the age.

 

[Stainless169]

When you take your supply and return air difference temps, this is called your delta T. You need to take the readings right at the unit, not at the registers. You need to drill a small hole in your supply plenum and your return at the unit for your temp probe. Then just screw in a couple of sheet metal screws when you are done.

I agree with this. I will have to take doors off of the unit outside until I find an area I can do this in. I will wait and see how my phone call goes tomorrow with the company I purchased this from.

 

[BD1]

I just checked again this evening. The unit is just outside his room. You can see his window in one of the pics again. I'm not sure how the duct routing is under the slab, but that is the closest.
The hallway outside his room:75
The temp coming out of his floor:62.6
12.4 difference.

Best bet is to get pressure readings for suction and discharge . Readings will vary depending on outside tempature.
As mentioned the delta T should be between 16 and 20 degree's.
A clean filter is a must. Discharge duct tempature will vary.


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[jbwilkins]

1981 insulated pretty well?

3-3.5 tons on a 1600sf house from the 80’s is probably pretty close....the old “rule of thumb” back in the 90’s was 1 ton per 500sf...in the Southeast...

Someone will tell you you should have had a Manual J to make sure it was sized right, and best case that would be good. However, without knowing the actual R values of the walls/ceilings and U values of the doors and windows it would have been a guess anyway...

 

[The Cobbler]

my circa 1950's house had a 1.5 ton unit in it, it would run all day and might shut off a bit when the sun went down. it would creep up on real hot days . It was like that since brand new when I was a teenager.
Replaced it with a much same BTU and higher seer ( don't remember the #) along with new windows, insulation in attic & basement and it cycles on & off even on the hottest days . stat is set for 72 and holds that even at 95+ outside temps
Just saying, it could be insulation related too

 

[Stainless169]

Update. I spoke with the company that installed it and they are sending one of there guys out tomorrow. He told me they will honor their install, no matter how long ago. He also said that I'm in range with return and vent temps since humidity is high around here. Looking forward to seeing what they say when they come out and look it over.

 

[fitter30]

Yes its 3 ton Temp difference 18*- 22*. 12* unit is not performing. That one pic where your hand is feeling the air blowing out that sheet metal drive that holds unit to supply duct needs to be hammered over and sealed just like the top. But thats not causing your low TD.

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