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OVERHEATING need PRO help please

1471 Views 5 Replies 3 Participants Last post by  rjordan392
It's 95 F outside,but sweating bullets cooking at 78 inside, yet I have the AC set for 73.
Problem seems to be air flow to upstairs with the new HE Carrier furnace.
The basement is super cool even with the vents closed. Last year with the old furnace I could just run the fan most days and move the air and it would cool down well even without the ac on.
I took the fresh MERV 8 filter out to see if the pressure to upstairs improves.
Also have floor baseboard return air vents through out upper two levels no RA in basement.
I haven't adjusted or made any damper changes since the new system was installed and the heat distribution was excellent. In fact I have taped and sealed ducts and boots to improve the flow. Do I need to do anything to tweak the AC distribution.? Should I fully open all heat vents to improve circulation?
Air is blowing cold, feels fine at the vents, just not getting high enough.
I have also improved attic and rooftop ventilation so the attic should actually be cooler than last year. So why is it so hot?:furious:
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Almost impossible to tell without being there. Sounds like time to get the installer back - something's not right with the new system.
If this is a certified installer for Carrier products, then you have a good chance of getting this resolved if the installing dealer is also good at troubleshooting the products. Get him back before the warranty runs out. Explain that the new system AC is not running as expected. I am not a pro but there are a number of reasons for poor AC. Just explain to him that if he cannot work out a solution that you will have to call "Carrier" to send one of their technical experts to assist the installer. If you don't get satisfaction from either, then its time to call an attorney and sue them both.

However, one thing you mentioned about is cooking. This can be considered as competition for AC due to excessive humidity and heat if its not properly directed outside via exhaust fans and closing off the door leading to the basement while cooking.
Was the house checked for heat gain and are you sure the ducts are properly sized? This is part of any AC installation job.

I went through a simular situation with a "Bryant" dealer and I contacted "Bryant" directly and explain the footdraging I was experiencing with the dealer. After no reply from them for two weeks, I emailed and called again stating that if they do not set up an appointment with me to come to my residence along with the installing dealer, that my next step was to see an attorney. That got their attention.
A Bryant techical representative called me back and ask for all the details of my problem and type of equipment installed. After hearing me out, the representative said he feels sure he knows what the problem is; but will wait until he sees the installation and put a test on the system before any recommendation.
The issue was resolved that day. All that was needed was a TXV (Thermal Expansion Valve) and a new upgraded thermostat.

Why it was not installed with the rest of the AC, I do not know. And why I needed a new thermostat, I do not know either.
I can only speculate that the installer (the owner and helpers) lacked some the knowledge that is required for a good working AC system. In the future, if I need service, I will have to call someone else because I should not have had to contact the "Bryant Company" to get the installer to correct the situation. Good Luck.

I forgot to mention to make sure all your return vents are fully opened.
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Updftae still hot and sticky

Ok, figuratively speaking I am no longer COOKING.Thanks, but still to warm and sticky.
So its 5:45 a.m. It stayed warm outside all night but the main floor temp did drop to meet the T stat setting of 73, after removing the filter and running at auto with ac on through the night. I would say the basement must be hovering around 60 or lower, but the top floor has stayed warmer than the main.
So to rewind, last year with the old Mid E furnace, on a hot day I could just run the furnace fan, a single speed and move enough air upstairs to cool things, most times with the AC off. Yesterday the stat was set for cool, fan in auto mode temp programmed to 73. Stat was reading inside temp at 78. I closed the 4 basement heat vents to force more air upstairs, no big changes.

This year the old AC is clearly working but the new Carrier 80000 BTU HE furnace doesn't seem to be pumping the air upstairs at nearly the same rate whether I set the fan for auto or high speed with the ac on.
So I think the ac unit is working fine but I'm wondering if the new dc motor can still move enough cold air upstairs or if my vents need improvement. I understand the principal of the new HE furnace with multi speeds and the new Carrier stat

Should I have to change any RA capacity to adjust for the dc motor. If anything we were more comfortable with the heat the last 4 months so air circulation seemed fine with the furnace on.

My returns are in wall at floor level, unobstructed. I have no returns in the basement. I have improved attic ventilation through added soffit vents and new roof with increased rooftop vents, so the attic should be less of a heat trap as well. Through the winter, I have taped and sealed the ducting on several runs going to the top floor and have not messed with any dampers. I also sealed my rim joist. No other modifications.

I have a total of 5, 8x16" RA grilles at baseboard level , 2 upstairs in 650 feet 3 on the main in 1000 feet and none in the basement. Do I need to enlarge these grilles or move them to ceiling level to move more air with the new DC furnace motor ?I know moving them up the wall to ceiling level would help but how much should it change. If the furnace keeps the house more comfortable in winter shouldn't the blower improve the ac function in the summer as well?
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Stat says it's now only 68 outside, so I guess we'll cool with the breeze for an hour or two , then close up again.
Airconditioning problems mostly need a hands on inspection. Like I mentioned before, I am not a pro and can only offer limited advice. It might help if you clearify what you mean by 2 return air vents at 650 feet etc. Are you refering to length of duct runs? That's a big house you got if thats what you mean. This information would help a pro along with size in btu of furnace, AC in tons, size of discharge and return ducts; both visable and in the wall sizes. Don,t go by the discharge or return cover plate size because the duct itself maybe smaller or larger; take the cover plates off to check. The dimensions of the house including amount of rooms to be cooled. Is it a single or a twin home? Height of ceilings, sizes of each room? Type and thickness of insulation in the walls and attic floor and is the attic ceiling vented properly.

These are the things that need to be taken into account for an qualified installer to evaluate the proper equipment to install.

Just on a hunch, I suspect that your Carrier system is the same as Bryants as I heard that it is so and your thermostat is basically the same as mine. But regardless, check your humidity setting at the thermostat. It usually should be set between 50 and 55% relative humidity depending on your own personal comfort.

In my own situation, my complaint was that my AC was cooling the house but was not removing sufficient humidity. The temperature on the main floor was 74 degrees but the relative humidity was 60%. A TXV and a new thermostat corrected the problem. MY system was only 1-1/2 years old before this correction.

Have you called in a technician to check your system?
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