r/askHVAC

Hey everyone! Former HVAC Tech but been out of the game a long time…I’m hoping to get some opinions from HVAC techs or anyone familiar with Goodman/Daikin equipment.
I have a system that was professionally installed in August 2025, and it has worked great for almost a year. This behavior just started this week, so I’m trying to determine what suddenly changed.
Equipment:
Outdoor unit: Daikin DC5SEA6010AA (5-ton, single-stage)
Air handler: Goodman AMST60DU1300AA
Thermostat: ecobee
I’m in South Florida, so humidity control is just as important as temperature for us.
Here’s what I’ve observed:
While the AC is actively cooling, everything seems normal.
The house cools properly.
Humidity steadily drops during the cooling cycle.
Outdoor suction line is cold.
I vacuumed the condensate drain and pulled a small amount of water out, so there may have been a partial restriction.
The strange part happens after the cooling cycle satisfies.
When the thermostat reaches set point:
The outdoor condenser shuts off.
The indoor blower continues running and doesn’t shutoff.
The airflow feels just as strong as it did during active cooling (it doesn’t seem to slow down).
During that blower-only period, the indoor humidity begins climbing again relatively quick.
Eventually another cooling cycle starts.
Thermostat settings
Fan = Auto
Minimum Fan Runtime = 0 minutes
I factory reset the ecobee and reconfigured it from scratch because I wondered if settings like AC Overcool, Cooling Dissipation, or Differential had somehow gotten changed.

TLDR: my unit that is less than a year old is cooling and removing the humid very well. However, the blower motor in the air handler runs nonstop and the problem just started this week. While it’s running, it rapidly increases the humidity in the house until eventually, this compressor kicks on and cools the house back down and dehumidifiers it.

We had a new build in 2020 with a builder grade unit installed. In 2024 we had problems and called a local HVAC company. This was a text from the owner:

“heard back from Rheem on your AC. Call me when you can.
- when unit was purchased there was no unit guarantee. So they will not change unit. But give compressor and coil to install…basically new unit.
-3 wk lead time on coil and 4.5 wk lead time on compressor
-$500 shipping and handling fee”

Paid $7,000 for an Amana 17.2 SEER with lifetime warranty. We recently had them come for preventative maintenance for spring service with a $300 annual fee. I had a family member at our house and they said the whole visit seemed off. I checked the ring doorbell and the tech was inside our home from doorbell ring to leaving in 2.5 minutes and brought in no tools or equipment. They never turned our unit off, confirmed with smart thermostat, and when I checked outside the ground was wet and they used our hose, but the back panel was dirty and had cobwebs like it was never removed. The invoice left only said “unit is healthy at time of service.” I requested more detail and got this:

Our skilled technicians tune up any brand of furnace. Keep your furnace running smoothly with a 20 point inspection and a tune-up.

Our trained technicians will advise you of any items needing repair, before they become major issues compromising your comfort.

Change customer supplied filter
Clear drain line
Wash condenser
Check dual run capacitor
Test contactor
Check refrigerant pressures
Check temperature drop
Inspect lineset insulation
Test condenser motor
Test compressor
Check indoor coil for leaks
Filter 20x25x1
Customer provided. Clean. Left in place.

Custom Job
Pres320/119R410,C-8.2a,fan0.8a
Cap45/5,contact-19
Indoor-4a

Is there any way to tell what was actually done? I don’t want to accuse them of doing bad work if they are doing what they say. The owner called and basically said they appreciated my concern and are developing a checklist for future customers so they aren’t confused on the service.

I've had a Nest Thermostat E in my house since 2020 with no issues. I live near Chicago and the last week it's been very hot. On Wednesday my HVAC system iced over inside my house (IE the compressor outside was not frozen). Had an HVAC guy come and look at it Thursday, cleaned my compressor coils, added more freon, etc. All working fine Friday and Saturday. Today (Sunday) it's frozen over again, but it hasn't even gotten above 80F here today.

I don't know if this is related but up until some time last week I was able to access my Nest devices in the Nest App, and then last week I got a notification that they're only available in Google Home. I have seen a lot of conflicting information about the Nest compatibility so I don't know if people have experienced a similar issue here. For what it's worth, my system's wiring is:

Y1 - Cool

G - Fan

R - Power

W1 - Heat

I have made no other changes, and would have thought that the issues prior to today could be explained by issues with the AC/compressor battling the extreme temperatures, but given my issues today along with the relatively mild environment, I don't know if there's a software issue or if I just need to upgrade to a different thermostat. My HVAC guy said something about how another customer with a Nest had an issue with it confusing her AC for a heat pump, so I want to eliminate any Nest issues before I try to replace the AC (roughly 15 years old, not urgently in need of replacement but could replace it soon).

Have a 3.5 ton Rheem unit that recently started to burn fuses. Unit is five years old. It was installed by a professionally. I’m relatively handy but not very used to working on HVAC systems. System went out the first time and it took me a few hours to realize it was the fuse in the disconnect box (learned a lot about start-up capacitors though!). Swapped the fuse like for like (30 Amp time delay) and the system fired right up.

About a week (we weren’t running it much) later I noticed a dead fan again. Checked the fuse and sure enough it was dead. Swapped it again and kept a super close eye on it. When it stopped I was out within 20 minutes and when I pulled the disconnect I noticed it was also hot to the touch. I checked the disconnect box and the connections all seem good and there is not obvious signs of arcing or connection issues. I pulled the fan and checked for ground on the compressor and that was fine and ran resistance checks and that was fine.

While going through all this I finally read the sticker and found that the min fuse size is 35 amps and max is 50 amps. The current disconnect box is 30 amp rated with a 30 amp fuse. My current plan (that makes sense to me at least) is upgrading the box to a 60 amp rated box and putting in a 40 amp fuse. Current wiring is 8 gauge to a 50
Amp breaker.

What I don’t understand is why didn’t the original
Installers do this, and why did it work for a few years until now? I feel like I’m missing something.

Neighbor is coming over tomorrow with gauges to run a pressure test before I change out the box.

Anyways, just looking for any ideas from this community.

Thanks!

The title. I know this is a bad heat wave but today is not as hot as yesterday and our house’s interior temp is still at 83 degrees. Is this normal? Does the AC need more time to go back to normal? Melting over here

I replaced my HVAC about a year and a half ago and had all kinds of issues with the install and the unit not dehumidifying sufficiently. To help with that — and to provide dehumidification overnight when the AC doesn't run much — they installed an AprilAire dehumidifier, with the exhaust ducted in just before the blower.

The problem: when the AC and dehumidifier are both running, the humidity creeps slightly higher and never comes back down. My theory is that the warm exhaust from the dehumidifier is warming (and compromising) the coils.

The manufacturer configured it so the dehumidifier shuts off whenever the AC is running, to avoid affecting AC performance. But it's still not working right. Here's what I think is happening: when the AC hits the set temp and shuts off, the dehumidifier kicks on. But before it can actually start dehumidifying, it seems to warm the space just enough to trigger the AC back on — which then shuts the dehumidifier back off.

With this setup, humidity sits around 65%, and the condensate drain line is just a slow drip. I finally turned the dehumidifier off completely, and now I'm at 55%.

At this point, I think my only real option is to duct the exhaust into the living space directly instead of routing it through the AC unit. I know that'll create a "hot spot" wherever it's ducted, but at least the dehumidifier should actually work.

Are there any other alternatives I'm missing?

How close can a mini split head unit be to a breaker panel? I’m putting a mini split in the garage and the best place for it is going to be about 15” above the panel and left side of the head unit will be about 10” right of panel.

We recently purchased a house and the master bedroom is the furthest from the furnace so it gets very weak air flow. The rest of the house gets quite cold but that room doesnt. I was looking at maybe getting a register booster fan would that work? Also the vent is 10x10 and I cant even find a register booster fan for that size. So what should I do? Is there another recommendation I should try? Im a complete novice and and not familiar with hvac or really DIY in general.

Thanks

Basement had about 1 foot of water. A/C stopped working so we called our home warranty company. Tech says it will cost $2300 to fix Blower motor and circuit. He wouldn’t try to restart it. I know he wants to do things the right way to not be liable. But honestly, could it be saved? Is it a way to check?