Ac indoor coil sizing.
Looking at the spec sheets for goodman indoor coils they have a CAPTA4230D3 2.5 to 3.5 ton and a CAPTA6030D3 3.5 to 5.0 ton. I am looking to go with a 3.5 ton system. The bigger coil has more surface area, and less static pressure. Is the smaller coil better for dehumidification, or is that old school thinking. They both are by the book. Looking for better dehumidification.
The spec sheets have the suction line at 1 1/8 for 3.5 ton unit. Unit is R32 any real world problem keeping it 7/8 it's only 38 feet long. I know warranties won't apply if it's known it 7/8.
Thanks
Comments
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Most manufacturers allow you input an equipment configuration along with your site specific parameters to calculate how the setup will function. in addition most manufacturers have refrigerant piping guidelines that call out pipe size reductions, as well as long lineset best practice. I know the brand I sell allows pipe size reduction with no issue on warranty, but it will reduce the capacity depending on length of the line. all of this should be supplied to you by the manufacturer.
for what its worth my manufacturer shows no change in latent capacity whether I use a 2.5ton only coil, or a 4-ton coil assuming i use the correct TXV and all else is the same but your coils may differ slightly
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To dehumidify choose least powerful A/C so that it runs longer. Theoretically the smaller coil will run colder and that enhances dehumidification as well. There's also systems with a downstream subcool/reheat coil.
Most practical & simple is to use a dehumidifier and set A/C for higher temperature.
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probably the bigger thing that will affect dehumidification is to slow down the airflow as much as you can. and turn off any post purge so it doesn't reevaporate the water on the coil at the end of the cycle.
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your increasing the capacity 50% I hope your increasing the duct size as well to Handel the additional CFM requirement's!
I find reducing oversized equipment is a better solution to high RH.
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i don't see what was there before mentioned?
other way to get better humidification would be a multi stage or modulating system.
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my mistake I saw 2 1/2 to 3-tons.
it sounds like he’s guessing at sizing.
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Possibly the best point about sizing. If there is an existing system in place, which sounds like there must be since OP is talking about re-using a lineset. How does the current system perform and what size is it?
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Going down a size from 4 ton to 3.5 ton System. Based upon historical energy usage the 4 ton was only running non stop a couple days a year from 12-6 pm. Goodman makes two coils that matches the 3.5 ton system. One is rated from 2.5 to 3.5 ton's and one is rated from 3.5 to 5 ton's. I am thinking the 2.5 to 3.5 coil will have more latent load, because it should be smaller surface area ie colder. But do i have that wrong because the smaller coil will have slightly higher static pressure.
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what is the physical footprint of the coils? usually one fits a different size furnace than the other without adaptation.
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Both the coils have the same foot print and case coil size. I Just looked they both weight the same. Could the coils be the same and they just have a different TXV installed?
They have to have some difference because the static pressure in the chart is not the same for both coils.
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The coil size aside have you considered a two stage outdoor unit as well?
Id use whatever coil matches your current setup the best and has the highest EER for the combination you're using.
If the published specs are essentially the same just go with the one that fits the easiest.
Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.
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The larger coil with more surface area will dehumidify better. The air will be in contact with the coil longer and lower static pressure is better.
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I am thinking you may need to consult directly with Goodmans sizing tools and plug in your exact equipment. When I check with my manufacturer its different depending on exact models. i had checked with some larger size coils on a 2.5t ODU and it made no difference, but when I check our 3.5t model there is some slight increase to the latent when when using a 5t coil (a difference of 300 btuh). my best advice is to do a thorough load calc, this will give you required sensible and latent numbers, then use your manufacturers information to make the best selection. there isn't just a general rule of thumb to this stuff currently as it has all rapidly changed (including testing process) over the last 10 years. each manufacturer is going to be slightly different. One thing that has not changed is that if you want the best designed system it will start with a load calc.
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I think the OP was talking about an inverter system. One model ranges from 2.5 to 3.5 tons. The other 3.5 to 5 tons.
If the manual J comes in at 3.5 tons, then obviously the smaller system.
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i think they are just evaporator coils that can be paired with multiple size condensers.
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