Skip to comments.Hot Time in the Summer - New AirCon Unit?
Posted on 06/21/2012 4:37:32 PM PDT by GRRRRR
It is summer for sure. Colorado is experiencing 90-100 degree F days in the north east plains. Forest fires, high winds and dust complicate the time we can have the windows open as even at 80Deg in the house, the low humidity makes it comfy.
The Carrier AC unit for this house (3,500+sq ft, 4BR, high ceilings) has had issues since I moved in. Refrigerant leaks and an electrical issue. Now, with the heat of the summer coming back, the AC unit can't keep up again.
I've cleaned the unit outside, replaced the inside filter and am still getting some freeze up on the line going into the plenum.
Air temp coming out varies from 60-70 DegF.
I think the unit is under rated. Can't find out what tonnage it is either. Model is 24AB300 which I can't find either.
So, what's the best AC unit out there? Trane, Carrier, Lennox or ??
Pricing on line ranges from $3-$8K as defined by size and install costs...LOL!
Finally, would they have to replace the exchanger in the furnace too?
Thoughts? Tks. G.
I live in Florida, where your A/C is a matter of life and death, and I will only buy Trane.
3500+ sq ft??? Are you the governor of Colorado? :-)
Thanks, naw...I finished of the basement, it’s pretty big...
What exactly do you mean by a freeze-up? And how did you determine that?
Hey ! The coolant line to the furnace has about 8 inches of bare copper pipe and ice freezes on the outside surface.
The outside unit copper pipe was missing some insulation (FIXED) and it had solid ice on it too.
Today, reached 98DegF and the air output temp at the register was running 61-65 DegF. Pretty decent I guess..
Make sure the registers are NOT wide open.
Freeze-ups usually indicate it is large of a system. It is cooling too fast, so it runs too little, and this prevents the humidity from being taken out of the air. You could probably add an extra dehumidifier in the house and this could help. I would also run ceiling fans to help circulate the air.
I have a large house like you have and have a 5 ton and a 2 ton. The 5 ton is a Trane (put in in 2006) that takes care of most of the house and the 2 ton is a Carrier that covers the bedrooms at night. Both are good systems, but I might replace the Carrier with a Trane if it ever breaks down. When I put in the Trane I replaced the entire system with new including all of the lines and the condenser because I didn’t want to be dealing with pinhole leaks.
Hubby and I own a HVAC company, but Chattanooga is a little far for us to make a service call :/
Hubby says the inside coil needs to be cleaned, its in a closet or the attic, you need to open the unit and clean them. A slant coil is easy to see / an A frame will have a panel you have to remove to clean. A HVAC parts house like CC Dickson should sell you a bottle of Green coil cleaner. Put some in a pump up sprayer and clean it up. If this still has the lines freezing up, call a service company to check freon levels, and MAKE them leak detect or add a stop leak sealant to the line set... Some service companies make lots of money ripping homeowners off not fixing leaks
The tonnage is is hidden in the model number, its 2 1/2 tons . This unit would work for about half your house. The unit is terribly undersized for 3,500 sq ft. This would not cool your whole home even working at top performance
I will answer anyones AC questions...
Great info, thanks very much from a fellow Zombie Hunter @5.56
Sorry... I meant to say that I think you have too large of a system installed now.
Also check your drains. If it is pulling out water, it needs to go outside the house by a drain. If water just sits in the tray inside your house, it causes problems with both comfort and freezups due to excess humidity.
Hey, thank you, but I don’t have such a coil set-up. I can pull off the side panel and will look the plenum coil.
We’ll see how it does now with the clean filter etc. over the weekend we’re targeting 102 or more!!
I thought so1 Excellent observation on the water...it is putting out water to the drain located in the dedicated utility room.
Checked the coolant pressure? Mine used to freeze up when the freon got low.
~~I meant to say that I think you have too large of a system installed now~~
The unit is undersized for the size of his house...
When you replaced your unit in 06, if the refrigerant type was changed from R-22 to R-410A, the line sets would have to be changed...
OK if you only have 2.5 tons, it is too small and not able to pull out enough humidity. There is an optimum size for a system and if it is too small or too large, you will have humidity issues. You need to find the sweet spot for your space.
I spent $5000 for a complete 5 ton Trane Puron system plus larger ducting in the house and a heating system. I think it is 16 SEER. The price included installation in 2006. I’m not sure what it would cost now.
Actually, that is exactly the opposite of what an HVAC guy will tell you - if you have a sufficient unit to cover your square footage.
In addition to lessening whole-house cooling efficiency, you're at risk of blowing out some of the ductwork, if you go around closing off unused rooms.
One last thing...
~~So, what’s the best AC unit out there? Trane, Carrier, Lennox or ??~~
Overrated... we install Nordyne equipment, made in America, 10 year warranty, and good quality equipment
~~Actually, that is exactly the opposite of what an HVAC guy will tell you - if you have a sufficient unit to cover your square footage.~~
Bingo! This HVAC gal agrees with you
That’s right. I was going to service the old system at first but after I got an estimate, I just told them to replace everything with new.
There are a couple reasons why the line set freezes up. If there is not enough air flow through the coils, the line set will freeze. Check your air return to make there are no blockage.
The other problem is a faulty TXV valve.
Thats all i know. I am on the commercial side so my advice might be skewed.
24AB300 This does not look like the entire model number for a Carrier. If it is a 2.5 ton it is too small for the house. It was most likely sized for the house before you finished the basement. Close the basement ducts and only try to cool the main living area. Do not use one of the pleated filters as they are too thick and restrict air flow. Use the cheap old fashion filter and change it more often.
I did discover a secret to running the auto air conditioner efficiently when I was ten miles down the road and sweating.
It has to be turned on.
did a cross check closest i could come was
24ABB3 Comfort 13
with Puron® Refrigerant
1.5 to 5 Nominal tons
Carrier Comfort 13 Air Conditioner with Puron Refrigerant, Model 24ABB3, is available in 1.5-5 ton nominal-sized units.
13 SEER / 11 EER
Sound as low as 74 dBA with accessory sound blanket
Reliability, Quality and Durability
Field-installed Filter Drier
Front-seating Service Valves
Internal Pressure-Relief Valve
Internal thermal overload
Baked-on powder paint
Dense wire coil guardStandard
Natural for them to freeze up in high use situations thats why they cover them with insulation but it could mean also you have a vacuum leak and are pulling moist air into the system if sot the compressor will freeze up and it wont work at all if it ws built in the 70 or 80 id get a new one replace the whole system i like carrier but i like trane better they see\m to last longer and have a heavier duty on off cycle
was the house built onto since this unit was installed ? if so it might be overworked !
Hey AP, thanks man, good to hear ya!
House built in 2006, original HVAC. Only change is the full finished basement, er...lower level.
All vents down there are shut.
Carry Onward and UP!!
I live in Texas hot weather - 100-108 degrees and I have a Trane. Keeps house cool.
If you’re having problems with freezing you’re probably low on freon. But if you want to replace it I can highly recommend Trane.
I live in Colorado 2,300 sq foot home down just north of Denver. My air unit went out and I replaced with a 4 ton with 5 ton exchanger. Bought a Lennox paid right at $4,000 through Costco. On hot days, maybe the house heats up to 75 if I have the air set to 72. Way better than my old unit.
For your size house I would say your needs are closer to 5 ton with a 6 ton exchanger. You might also want to look into the possibility of a dual zone with two 3.5 ton units but that would require you split your air handling.
As energy cost rise, so will the popularity of smaller homes in nice areas. In fact, it's already happening.
I would go with a Lennox. Made in Marshalltown Iowa for 110 years. We have a Lennox heat pump that was installed in 1995. It runs 12 months a year here in Greenville TX and we have never even had it serviced.
Carrier is good. Also York has some good products.
Everything really needs to be sized right. The blower and a/c coil need to be the right size. If the blower is too strong air will be too warm, going over coil too fast. If too weak, the coil will ice up and no cooling.
Often having both units be from the same company makes things easier and if they are both replaced at the same time one part won’t be older and closer to replacement.
Ya gotta remember cold air falls if you have ceiling fans reverse them to pull the cold air up off the floors and keep lower levels doors closed
get into where your A coils is that's the keys shut off your unit and let it thaw out take a squirt bottle of Windex and spray down the coils then use a strong shop vac with a brush attachment gingerlycleanall the dust out of the coils Windex will loosen it up so it will pull free from the coils ...
Next if you can unplug the squirrel cage and pull it out clean the dust off the blades real good dog and cat dander can really slow down the cage speed hence it will not cool your house efficiently i recommend doing this twice a year for the cage and change your filters once a month ....
Hope this helps it will keep your house allot cooler
remember don't smash down those fins on the A coils because smooth airflow through those coils is a must for a cold house in summer !
catcha on the flip
I read yours and others comments more closely and saw you had a two and a half ton a/c for a 3500 sq ft house. That is way, way undersized. I had a 2.5 ton prior in my house that was undersized for my house and mine is less than half the size of yours. I now have a 3.5 ton and it’s good. You’d need a 5 or 6 ton unit.
It also can freeze up if the blower is set too low, the cooling coil will freeze up as the air isn’t flowing by it fast enough.
Happy Fried Day to AP and ALL!
Mercury hit 105 at the house today and the AC seems to be handling it just fine.
Cleaning the filter and stuff seems to have helped very much. AC output air temps ranged from 61-64 DegF all day, house stayed nice and cool.
Thanks for everyone’s input and have a FINE WEEKEND!
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