Good vid. Your 20 by 25 return makes good sense as if you use a pleated filter, you will need the extra square inches for pressure drop across the filter. I also noted that the vent connector was single wall to the vent. We do not use any single wall anymore up north, because the low vent temp of the newer 80% furnaces will rust them out after several years. Again, good work. GFM
My kind of videos.........sizing-calculating and correcting ductwork. Teach an old dog the old tricks that this old dog never learned,lol. This is what I have always loved about hvac, there is always something to learn if you are willing. Doesn't matter how old you are or how long in the trade, you can still learn something every day. August will be 34 years in hvac and June I will be 54 years old. Soaking it up like a sponge,lol. Take care, Brett
That duculator is not needed for residential. It isn't. A 1200 square foot home, for fucks sake put a 25 by 20 return grill in and run some 22 by 12 or 24 by 12 duct. Then come off the supply with a 18 by 10 to a split with two 12 by 10 dropping to 8 by 10 at the end. A 5 ton system is obviously doing 2700 sq ft or so so you know you need two fat returns in two locations and enough supply (22 by 12) to get the air off the unit. That shit ain't needed for residential. It isn't. If you use that thing in residential, you BETTER have a sheetmetal shop and be making all your duct. If you're going technical like that, you gotta build your duct around that duculator. Don't turn simple into complicated just to feel smart. Residential is easy. I worked for a guy in my area and he did million dollar homes custom fabbed duct. People paid his price. He never pulled out a fucking duculator.
Thanks for pointing that out, here I was just trying to save the equipment from dying a slow and painful death again!!!!! I never took in account the environment. Thanks for that!!!!!
I have found out the older I get the more I learn and the easier I pick up on things, it is never to late to learn! If someone says there nothing else to learn and they already know everything and cant learn more about it they lie, I learn more almost every day about something! Duct sizing or anything to do with duct is a good thing to learn I have a couple different duct calculators I sit and study sometimes even though I am not working! Take care
Did you drill some holes and take some static pressure readings across the ductwork and cooling coil? Best to establish a baseline first. Most of these residential type units are only rated for .5” total static. Your probably over 1”. Duct liner just ads to the problem. The duct calculator is looking at pressure drops of 100 feet of straight ridged unlined duct, so the liner, elbows, transitions, etc have to be accounted for separately. One bad fitting can kill the airflow in these low pressure systems. You are correct about the one sided return. That’s killing you. You need to use either the whole bottom or both sides for RA. Maybe you can ad a little outside air to make up some of the RA shortage. You’ll also have to have at least the area of two 20x25 filters for that airflow. Otherwise the filters will just be a restriction, and the dirt will go right through them. You’ll have to do a slant or V track if you use standard filters, or some sort of high capacity media filter with enough surface area for your airflow.
Thanks for the video... I have a 5 ton with 2 returns: Flex 12" and 16". Do you mind telling me if that's enough? Each AC guy is telling me something different. Thanks for the help.
Question-Since you ductulator is only for galvanized ductwork. Have you taken in to consideration the friction rate of the two different surfaces of the inner liner and the metal? And another solution is you can cut out the other side and make a "wrap around" duct back to the left side to pull the air thru.
Hey Brett, what can I say to this comment!!!!!! It's comments like this that makes me wanna make more of these videos!!!!!! I know my camera work sucks sometimes but I'm trying to fix that to make my videos better!!!! Thanks for watching Brett!!!!!!
You are proving a very solid point here though!! It's better for the environment for people to do things right, without that the best equipment in the world is null & void on a crappy install!!! Very good video I hope homeowners etc etc this!! :D
Without a filter in place the coil must be partially clogged, further increasing static pressure. Did you take a static pressure reading on return and supply? By taking actual readings you know which is the biggest problem supply or return. If the static is even hgher than the duculator would show it to be with the given ductwork you know there is further problems like dirty coil or kinked ducts in the attic. A reading across the coil would indicate if the coil was clogged. I don't remember how much pressure drop is due to a clean coil. Can anyone supply that info?
That initial setup was terrible, a small 16x20 for the filter, wow. IMO, 5-Ton units shouldn't be put in resident's; with a 4-Ton you can use as low as 1400-CFM; 350-CFM per ton...! First of all, my ductulator @ .05 FR says for 1800-CFM it calls for more than a 22" Flex duct which would provide only 1735-CFM With FR @ .05", of course that could be allowed to go higher to cover up-to 1800-CFM. You can't use a ductulator to size Return-Air filter areas; because the open air-area (Ak) of a filter is probably only 60 to 65% of the filter's measured area. If using Purolator #312 filters you need less than 300-fpm velocity. Therefore I would want (2) 20x25 filter rack areas going directly back to the blower. A 20x25 filter is a measured 19x24 = 456-sq ins * 2 is 912 * .65% Ak is 592.8 sq ins / 144 is 4.116666-sf (Ak) 1800 / 4.1166666 is 437.2- fpm velocity well above the 300-fpm required...!
Ouch.. this is painful to watch.. this is what happens when a homeowner hires the handy man to install an AC unit because he is way cheaper than a licensed contractor..
Good vid. Your 20 by 25 return makes good sense as if you use a pleated filter, you will need the extra square inches for pressure drop across the filter. I also noted that the vent connector was single wall to the vent. We do not use any single wall anymore up north, because the low vent temp of the newer 80% furnaces will rust them out after several years. Again, good work.
GFM
My kind of videos.........sizing-calculating and correcting ductwork. Teach an old dog the old tricks that this old dog never learned,lol. This is what I have always loved about hvac, there is always something to learn if you are willing. Doesn't matter how old you are or how long in the trade, you can still learn something every day. August will be 34 years in hvac and June I will be 54 years old. Soaking it up like a sponge,lol. Take care, Brett
That duculator is not needed for residential. It isn't. A 1200 square foot home, for fucks sake put a 25 by 20 return grill in and run some 22 by 12 or 24 by 12 duct. Then come off the supply with a 18 by 10 to a split with two 12 by 10 dropping to 8 by 10 at the end. A 5 ton system is obviously doing 2700 sq ft or so so you know you need two fat returns in two locations and enough supply (22 by 12) to get the air off the unit. That shit ain't needed for residential. It isn't. If you use that thing in residential, you BETTER have a sheetmetal shop and be making all your duct. If you're going technical like that, you gotta build your duct around that duculator. Don't turn simple into complicated just to feel smart. Residential is easy. I worked for a guy in my area and he did million dollar homes custom fabbed duct. People paid his price. He never pulled out a fucking duculator.
Hey Darren, thanks for taking the time to watch!!!!! It means a lot!!!!!
Thanks for pointing that out, here I was just trying to save the equipment from dying a slow and painful death again!!!!! I never took in account the environment. Thanks for that!!!!!
I have found out the older I get the more I learn and the easier I pick up on things, it is never to late to learn! If someone says there nothing else to learn and they already know everything and cant learn more about it they lie, I learn more almost every day about something! Duct sizing or anything to do with duct is a good thing to learn I have a couple different duct calculators I sit and study sometimes even though I am not working! Take care
Did you drill some holes and take some static pressure readings across the ductwork and cooling coil? Best to establish a baseline first. Most of these residential type units are only rated for .5” total static. Your probably over 1”. Duct liner just ads to the problem. The duct calculator is looking at pressure drops of 100 feet of straight ridged unlined duct, so the liner, elbows, transitions, etc have to be accounted for separately. One bad fitting can kill the airflow in these low pressure systems. You are correct about the one sided return. That’s killing you. You need to use either the whole bottom or both sides for RA. Maybe you can ad a little outside air to make up some of the RA shortage. You’ll also have to have at least the area of two 20x25 filters for that airflow. Otherwise the filters will just be a restriction, and the dirt will go right through them. You’ll have to do a slant or V track if you use standard filters, or some sort of high capacity media filter with enough surface area for your airflow.
nice video. i usually size new ductwork for .08 supply and .05 return with 1.5cfm/sq-in for the filter. thanks for making videos.
Everyday is a school day for sure, like you said if you don't learn something everyday you've wasted the day!!!!!
Thanks for the video... I have a 5 ton with 2 returns: Flex 12" and 16". Do you mind telling me if that's enough? Each AC guy is telling me something different. Thanks for the help.
It's going to be fun for sure!!!!!!! It's going to one of those jobs I will have to do at night!!!!
Question-Since you ductulator is only for galvanized ductwork. Have you taken in to consideration the friction rate of the two different surfaces of the inner liner and the metal? And another solution is you can cut out the other side and make a "wrap around" duct back to the left side to pull the air thru.
Hey Brett, what can I say to this comment!!!!!! It's comments like this that makes me wanna make more of these videos!!!!!! I know my camera work sucks sometimes but I'm trying to fix that to make my videos better!!!! Thanks for watching Brett!!!!!!
You are proving a very solid point here though!! It's better for the environment for people to do things right, without that the best equipment in the world is null & void on a crappy install!!! Very good video I hope homeowners etc etc this!! :D
Thanks GFM
Without a filter in place the coil must be partially clogged, further increasing static pressure. Did you take a static pressure reading on return and supply? By taking actual readings you know which is the biggest problem supply or return. If the static is even hgher than the duculator would show it to be with the given ductwork you know there is further problems like dirty coil or kinked ducts in the attic. A reading across the coil would indicate if the coil was clogged. I don't remember how much pressure drop is due to a clean coil. Can anyone supply that info?
Thanks for the video. You keep saying .5, but you meant .05, right?
That initial setup was terrible, a small 16x20 for the filter, wow.
IMO, 5-Ton units shouldn't be put in resident's; with a 4-Ton you can use as low as 1400-CFM; 350-CFM per ton...!
First of all, my ductulator @ .05 FR says for 1800-CFM it calls for more than a 22" Flex duct which would provide only 1735-CFM With FR @ .05", of course that could be allowed to go higher to cover up-to 1800-CFM.
You can't use a ductulator to size Return-Air filter areas; because the open air-area (Ak) of a filter is probably only 60 to 65% of the filter's measured area. If using Purolator #312 filters you need less than 300-fpm velocity. Therefore I would want (2) 20x25 filter rack areas going directly back to the blower.
A 20x25 filter is a measured 19x24 = 456-sq ins * 2 is 912 * .65% Ak is 592.8 sq ins / 144 is 4.116666-sf (Ak) 1800 / 4.1166666 is 437.2- fpm velocity well above the 300-fpm required...!
Lol the dryer vent
Good videos, Thnx
sure are a lot of units outside there.
Hey can you send me a ductalator
Ouch.. this is painful to watch.. this is what happens when a homeowner hires the handy man to install an AC unit because he is way cheaper than a licensed contractor..
2:14 LOL