HVAC help - 1yr old AC not really cooling

Hoping for some help. Currently in NJ on a project build, and it seems every HVAC tech around here either says “I didn’t install it, I won’t work on it” or “I moved a wire, that will be $600…. Okay how about $200?” It truly feels like everyone is hacks out here. I'm no HVAC guy, but know enough to know when something is wrong - and this feels wrong.

One year old Trane System (s9v2). Struggling to keep up with the 96+ days we’re having here. Insulation in the attic/walls is subpar at best, so my expectations are muted, but I’m not feeling much airflow at all from the vents – even the close ones to the trunk. Felt moderate airflow during the winter, and very low airflow now in the summer. In my googling, it seems like the s9v2 has a variable speed fan, but it seems to be at around 40-60 cfm based on the internal readout and not pushing much air whatsoever. Latest tech said (and I’m paraphrasing) “new systems don’t push much air quickly, they just stay on longer.”

Relatedly, the ducts are sweating at the furnace trunks. Could the compressor be trying to get the air colder and colder and colder to overcome the fan not pushing any damn air out?

Third issue, the last tech saw it was low on refrigerant and topped it up. Said it was impossible to be that low without a leak on a 10mo old install, so he suggested we try a bigger company to come out look at it. Apparently, Trane warranties parts, but not labor when it’s a manuf defect? Again, a lot of “not my system, not my problem.”

 

When was the last time you changed your air filter?
it sounds like your coil is frozen, you need to turn the system off at the t stat but turn the fan to On to help melt the ice. Either low on a charge or dirty air filter

 

Trane has a 10 year parts warranty and usually the shop that put it in will give a one year warranty on labor. Have you tried to call the original company that installed your system?

 

The owner is currently knee deep in a few court cases related to his hvac business, so needless to say does not have anyone to service. Moreover wouldn't be allowed in the house.

Filter was changed two weeks ago. Should be topped up on charge as of this morning, but seems to my uneducated mind to not be pushing enough air.

 

Any signs of the unit freezing up at the evap or back to the compressor?

 

Low air flow, sweat on the ducts, I’d say yes, coil needs to be thawed out

 

Check condenser, see if it’s frozen. Maybe you got too big condenser

 

It's low air flow even after being off for two days. So I'll give a shot, I'll try damn near anything at this point.

 

If its low on gas it will freeze up fast, especially if it’s humid, you can look outside at the service/Schrader ports, look, feel and taste for oil, oil leaks out with the Freon

 

Hell - at this point I'll gladly pay anyone their asking price just to get this shit figured out.

 

AC guys are known to sell bigger units then u need. When you turn on AC the unit will frozen your coil, then ur fan can’t push air through

 

If I was closer I’d be more than willing to help you out, sorry.
As as winning just said, AC salespersons are snakes, same with most “techs”

 

You could check and see if your fan settings are set up for higher speed on heat and lower speed on cooling. You can look at the schematic shows low, medium, and high.

As for the leak, you most definitely could have a leak on a brand new unit. Leak doesn't necessarily mean failing part as much as it probably means crappy install. I use to work for a big AC company here in AZ. We did 80% of all new homes built here in I can't tell you how many houses I went to that had issues that should have been caught during original start up. Leak is probably at one of the joints in your lineset and not in your coils.

 

I like your thinking with the fan speed setup, sometimes the speeds need to be adjusted depending what outdoor coil or other features installed

 

Heck, help me troubleshoot remotely and I'll gladly pay for your time.

 

https://www.calculator.net/btu-calculator.html
use the link and check if the the unit match ur house

 

Looks to be a 5ton external. Rough measures on that calculate give me a 4.3ton or 4.7ton depending on if I call it very shady or not.

Turned the AC off 10 mins ago, and left fan on. Compressor fan is still running outside. Should it?

Lineset outside definitely feels like there's some dry oil on it.

 

Shoot me some pics of the schematic on the inside of your furnace door and I can tell you how to wire the fan if avaliable.

As for the leak you'll need some equipment to do that, not an easy task without the right tools. You could visually inspect your line set from the furnace to the condenser as much as you can to see if you see any freon on it. It will be oily not watery. Main areas to check are where the lineset attaches to the furnace, attaches to the condenser, and any sharp turns where they could have brazed a coupler in.

 

Compressor should not be on still. Pull the disconnect and reinstall after about 10 minutes with the Stat Still off and see if Compressor kicks on again. Wipe away the oil you see with a wet rag and dry it off before turning unit on again. If oil comes back you've probably got a leak. Sometimes oil is left there when they start unit up so this is just ruling that out.

 

Flipped the breaker shutting off the compressor.

Images of diagram should be below.

 

Sorry, doing this from my phone. This section says there is another chart somewhere on how to do an airflow adjustment.

 

holy crap nice find. thats a digital readout menu. attached is an image with the current results and menu overload.

Not 100% sure, but the unit outside looks to be a 2.5 ton. (4TTR6030J1000A). Also it seems all the values are just defaults, not actually set for this house.

There is an error code for E17 - "Blower Motor No Communication Response" was stored in the last 6 error codes. No idea when that was stored, but I cleared it so if it pops again we'll know closer proximity.

Lastly, figured out why the compressor was staying on. There are 3 thermostats in the house going to three zones - the installer has them all call the furnace to run AND control dampers. I turned off the main thermostat, but two others were still active. Totally user error.

 

Edit. It's a 2.5ton based on googling the model number. So odds are we're light?

 

Shoot me a picture of the model numbers. Tonnage is in there divisible by 6 or 12.

 

Can you set the AC to 450 cfm and see if that helps the situation? I'm not sure if they left instructions on how to access that menu or not.

 

That's a 2.5 ton. What about furnace? Also since we're looking into it. What's the sqft of the house?

 

Roughly 1000 above ground and 900 or so below ground.

Moved the CFM to 450. Now 1180 cfm ongoing (was 870 before). Much louder, much harder draw, and better air from the vents. Feels like air is actually moving now. Does have a bit of a vibration to it now though.

Furnace 1st Stage Input BTUH - 52k.
Furnace 2nd stage Input BTUH - 80k.

 

Round here we do 300-400sqft per ton on regular homes and bump up or down depending on conditions. I'm not sure how they do it with below ground areas but I do feel your unit is under sized. Maybe @FrenchToasty knows more on this?

 

You mentioned dampers - could one or more dampers be stuck closed? Just a thought.