Video

Conduit v Duck?

Thanks for the video, but if you posted a link to a video about branch run sizing it would be more helpful for us and your channel exposure.

Shouldn’t the size reduction be installed immediately after the 5th takeoff? I know that the sketch is not to scale, but the sketch shows it midway between the 5th and 6th takeoffs. It might be helpful to illustrate, or mention, that the transition can be placed a short distance after the 5th takeoff to save materials.

I am adding 800 sqft to my home (1,400 existing + 800 new). Got quotes from 5 contractors so far. They are telling I need to upgrade my furnace and AC. The recommendations range from 3 ton to 5 ton.

Wow💛💛🧡🧡🧡💚💚💚💛

Could you just use the CFM = Room Sensible BTU x (1.1 x TD) … and not use cooling factor?

Havent heard this stuff since Occ college..😅

Hi Ed! I have a question about EL! Imagine that! Anyways, out in the field I am running a supply trunk & tapping off with saddle taps/dampers straight to the supply registers. In the Wrightsoft program that I am using it seems to give me multiple options but all with different EL. Option (A) Tee, no transition (B) Branch EL of round take-off (C) Trunk EL of round take-off. WHICH ONE DO I CHOOSE?! Thank you in Advance!

This is why, as tech oriented as I am, tech is not a thing people should put all their faith into. Even tech fails.

What is the equivalent length for a round pipe attached directly to a plenum in a return air system with a referenced velocity of 700 pm at 0.08 IWC per 100 feet? How to calculate, can someone explain thank you

Question: I have 17 feet of 6 inch duct supply to a room. After 17 feet, it elbows down and to the right, travels 2 feet straight, then elbows up and into a transition piece that feeds the room. Do I need to reduce the 6 inch to 4 inch OR simply get rid of the elbows and install a 45 set about 4 feet before the transition piece into the room?

Hi Ed I have a few questions for you. 1. After you reduced in the example.. won’t your last few runs “run out of velocity” on the end? (Just like when you took off your velocity dropped in the beginning?). 2. Is it acceptable when using round pipe to reduce 4 sizes if need be? I.E. let’s just say that I started with a 16” round pipe and at half my velocity I needed to reduce to a 12” pipe. Would it be acceptable to put 2 reducers together and go from a 16” to a 12”? Thank you

Thank-you! I’m not an HVAC expert, just an old, retired soldier, systems engineer...and woodworker, trying to keep the wood dust out of the air - and now, the smoke from all the wildfires in Canada, Michigan, Pennsylvania... I’ve been trying to get a better handle on “pressure loss” across a furnace filter. I’m having trouble finding data. I’m also wondering about the surface area of the filter media in different pleated filters, different thicknesses, and different MERV classes. Recently noticed that a five inch MERV 13 filter appeared to create a much greater “restriction” or pressure loss, than expected. Any guidance would be most appreciated. Thank-you!

I simply took the equation provided in Manual D and put it into a spreadsheet. Enter in the values and it automatically adjusts the EL value. Very handy to have. Especially if you end up with a friction rate value that isn't 0.08 inches wc or want to size based on a lower velocity than 900/700...or both! You can play around with different values to bring down large values and "dial in" a duct system.

Love your videos!

Best video out there!!

3m/Filterate definitely do not publish accurate 'initial resistance value (WC)' that they print on their products. If a real consumer advocate group tested their products, they would be forced to change the printed information to double or triple those figures at those CFM ratings. I am an HVAC business owner and have tested these filters in numerous MPR/Merv ratings, plus different system designs and they are not even close to those numbers. I easily saw double the values printed in every system tested. Unsuspecting people put those in their furnaces or air handlers thinking they struck gold, but they got fooled by fancy wording. They are junk and it is best to still with a better filtration system instead of wasting money on that garbage. But all brands should be forced to print some accurate data just as the EPA makes companies put out accurate information for items they regulate. False advertising at best, but really it is fraud. Love you videos, btw!!

Where can i downlad this paper calculator?

Im so confused. WHAT IS FRICTION RATE? I've been researching for hours, and I don't understand this term. You also brought up a good point, how can we determine what filter the system can afford??

Hey if I put supply grills straight into duct 24x10 does the grill size let say 10x6 have the same cfm as say a 10x6 square duct not sure on how to size with grills going straight into trunk line thanks for any response

Good info, great acronyms!

I've been trying to learn how to do basic calculations on what size ducts are suppose to be on an existing unit. I'm a service tech and never really learned about the duct sizing and sizing of a unit. I need to know these things. It's so beyond frustrating to me because I feel like I'm so lost. Every single video I've ever watched it almost seems like the people teaching are teaching in a way as though the students already knows most of it instead of teaching a 5 year old this stuff. I wish there was like an extensive three or four hour video starting from the very very basics. When I go on a service call and a customer complains that their room is always warm, I want to know if the unit is sized right and if they have the proper air flow going into their room. I'm at the point now where I'm about to just give up because I feel like there's so many missing pieces.

Where do you get equivalent lengths for standard fittings? Obviously Menards isn’t giving out data sheets with their generic duct pieces 🤔

Where did you find the .03 value for supply outlet and for the return grille? Is this the sum of the grilles in the total system or the sum of the grilles along the total effective length or some type of standard value, as I see it everywhere in pressure loss discussions???

Hi Ed, does the size of the duct fitting change the total equivalent length?

Hi Ed just makin sure now, the friction rate is on each manual of the air handler depending on the speed of the blower? And we have to match that friction rate based on how we calculate sp, pressure drop, equivalent length, etc after the design is complete correct?

What about a double plenum? Would it be: •@12’ on each side

We are getting a new HVAC system and they guy is insisting on putting in a 1” or 2” filter. I thought a 4” filter provided the least static pressure, and thus would maximize the life of my system. Who’s wrong? Thanks for the great info in the video!

Please explain Mr. Janowiak, what exactly is Effective length? Is it the amount of air we are losing or the amount of air coming out of the blower motor?

Excellent video! Very clear. Much appreciated!!

Thank you Ed.

Awesome video Ed

Good stuff…can I get a fanny pack?

🍻

When I tell people how large their filters have to be they look at me like I’m a purple polkadotted unicorn with warts growing on my face. Before high school my father was teaching me to size a filter at 200 or below face velocity Per square foot. More people need to make more great informative videos about filters and face velocity and pressure loss they are greatly needed. Placing two or three large filters in parallel should be the norm not the abnormality

Thanks Ed, Merry Christmas!

You awesome Ed. Dew point gang

Hey Ed, the content is great! Looking forward to more videos

We finally get to see you again 🤠. Been to long since your last video 🤣

Should I reduce my return in size as well? Or keep it the same size the entire length

Do you teach classes? If so when and where?

Love your videos. Would you be will to come on a live HVAC CZcams show for an hour?

Great video

Really good explanation. Unfortunately, in my country (Brazil), the manufacturers usually don't give us a good performance data as you showed.

The manufacturer that publishes the CFM vs Static Pressure is 3M. No surprise that it's a Minnesota company, right ;-)

Ed, what is it that we are supposed to calculate?

Question. Is it ok to reduce the duct work (let’s use your example) after we take first 3 branches, when the duct work is in unconditioned space to reduce the use of the materials and reduce the surface area of the duct work. So we can save few dollars on insulation and metal and also few BTUs?

control + C is copy, control + V is paste.

Hey Ed, what are the consequences of falling outside of the Acca wedge friction rate chart? That is .06-.1. This happens often when I try to size a duct system for a low pressure ducted mini split. Or with a conventional unit when my duct system is too long due to a tight, large custom home. Thanks!

Thanks Ed. I'll use this for our company training