How to Test HVAC Room Pressurization (Zonal Pressure Testing for HVAC Commissioning)
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- Опубликовано: 29 сен 2024
- Using a TEC DG-8 manometer and a Testo 400 hot wire anemometer (www.trutechtoo..., Corbett evaluates the HVAC balancing in the home his family built in Atlanta. Keep your room pressures below 3 Pascals if you can, 5 Pascals will start to give you problems- rooms don't receive enough conditioned air, and/or whistling or doors closing from 'ghosts'.
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yes we do like the longer content. great work here breaking it down.
Hey Nuckolls! Thanks man!
Will dents in ducts be a cause of zonal pressure issue? Or would those dents only cause lower CFM at that specific supply vent?
Hmm, interesting question. I guess it would make the duct smaller, essentially, which would drive up static pressure on the fan and lower airflow from the duct. But the zonal pressure effect on the room would actually be lessened.
@@HomePerformance so as an the effect of dented and damaged duct work, you'd catch it in the static pressure testing, I see!
More nerdy = more better!
Is there a guide on how to design bypass ducts to reduce noise transmission?
I want to keep bedrooms as quiet as possible, and one of the best ways to seal out noise is to have a tighter fitting door with small undercut. As you point out though, this either requires a return duct or a bypass, but a bypass can allow noise just like a large door undercut.
Tips? Suggestions? I’m thinking offset grilles in a stud cavity with some sort of internal sound insulation that doesn’t block too much airflow.
Darn! Jake Nuckolls beat me to it!
I was going to say the same thing; a lot of us do like the longer content - especially myself.
After all, a lot of us are on here seeking more information or a higher learning in HVACR. Others simply just want more comfort.
I've learned a lot from your channel, and I'm an HVACR-Tech-in-the-making, (still in college right now; about to start commercial HVACR next semester).
I really enjoy learning about the whole Manual J/Heat Load Calculation aspect of HVACR.
I don't know why, but I've always been attracted to the complexity of certain subjects, and your videos are helping to pacify that thirst.
Thanks, Corbett!
Cool man, we will keep trying to satisfy everyone’s nerd thirst for this topic! I certainly have dozens of ideas constantly on The List. Keep up the good work in school, I hope we get tons of other smart young people to follow your lead.
If I understand this correctly one of the problems high pressure in the room equals to different temperature from the rest of the house
possibly higher energy cost is there a health problem for people?
Very nerdy and detailed, Love it! Since most homeowners cannot afford a $500 manometer and other tools like that, it would be cool to compare your calibrated, quality tools to some of the more popular and inexpensive versions you can acquire. Even if they aren't dead on, they might be reliable enough to give homeowners a starting point to work with HVAC contractors.
Interesting idea, Judman- I’ll think on it
I have a $50 manometer and it works just fine for stuff like this. You just need to be in the ballpark… nailing exact measurements down to the 100th of an inch of water column is not necessary.
It’s also super handy for measuring pressure drop across furnace filters and other nerdy stuff like that. Money well spent if curiosity about these things keeps you up at night.
@@superspeeder But to measure 2 to 3 pascals, that's around 0.01 iwc, so you would need a very high resolution (to the hundredth decimal) manometer if it only reads in iwc. What res does your $50 man do?
You have this great way of compelling me to spend more money to do better diagnostic work to generate greater value for consumers' money spent. Rock on (and, I signed up already...proof social media works 🙃)!
Hey, what a great compliment Greg! Thanks man!
I came across this video because we just installed a new AC unit and air handler. Since the install I’ve had a really bad case of tinnitus where I cannot sleep in my bedroom because the pressure in there is horrible. I have humming all night long in ears. I have to sleep in the living room. How does one go about fixing this will help? It’s disrupting my way if life. They replaced ducts also but not thru the house just the k es that lead to ac.
Something that confused me when I tried to do my own calculations is you don't appear to actually have a 1" clearance beneath your door: 65.3cfm / 396fpm / 36in = 0.66in. Other than that, fantastic video, I really appreciate the in-depth explanation. This is helping me check my own door undercuts and whether to do jump ducts. The answer, unfortunately, is yes -- I'm calculating ~10Pa with 32" doors and 0.625" clearance at ~150cfm.
Installed an 8 inch jumper from my master to another space because the room would constantly pressure up. Great content.
Nice, Nick. Thanks for following!
Whoa! I kinda followed along - but then I'm a Google nerd, not a HVAC in the weeds nerd. That said, this is a great video for the HVAC nerds. :)
Ha, thanks for taking the time Bill, as always!
Hi, not to change the subject, but have you heard of high frequency waves going up to 22KHz in an appartment building. I catch this on Advanced Spectrum Analyzer from playstore. I read on forums that these waves are not audible to the ear but to the skull neck chest abdomen and legs. Some people might feel mini vibes with resonance and pressure, especially when balcony doors are closed and no other noises are noticeable. Even when the wifi is off. To feel these you need silence. Writing to you from France and haven't had any straight answers yet. Some say it's from relay stations and got to do with volt meters to start with, others say mechanical or electrical.....thanks much.
The extra layer of nerding out got me to sub
Nice, Trey. Welcome to the cult.
I think I know what tool I will be purchasing in the very near future...
I've been looking for a video like this for a few days. Thanks!
My home is 5 years old. Every winter we have issues with doors and locks freezing shut. We tried everything from lowering humidity inside the home, we changed locks so many times, getting home inspectors involved to see if hvac or vents are not working properly. As of the moment we are looking into getting storm doors installed to help with the frozen doors and locks issues. One home inspector mentioned about getting the pressure in the home checked, we spent so much money on fixing this issue could you please enlighten me if this is necessary. Thank you so much.
Yes, highly recommend. You can get a high quality digital gauge yourself nowadays for $600, and you’ll have some answers:
www.trutechtools.com/tec-minneapolis-dg-8-digital-pressure-gauge-kit.html
Is the Testo 510 accurate enough for these test ?
As always, a great video (and aptly timed for me as I'm about to DIY duct design for our new house). Would you mind sharing the stair railing system that is shown on your stair case?
Thanks- it’s RailFX
This was timely. I was really tempted to make a conditioned attic in my retrofit but it’s just not in the budget. I won’t need to run returns to all upstairs bedrooms if we nail our Man D.
The best hvac systems have RA in each bedroom. I’m from Calgary, Canada. By code we only need 1 per floor but it we always get 1 RA per bedroom. I’m in HVAC.
How do you test air pressure fluctuation in a single space, with out reference to another space?
All pressure is a differential measurement, so you have to have a reference.
and the next question is, how well does carpet seal the door?
also interesting that you have wider doors than us.
we have a few problems with poor man hvac systems not having returns installed, causing depressurization of the main room, causing back drafting of fireplaces.
Of course if you don't have a designed system, then all bets are off. This type of test would be a forensic tool to figure out what's wrong, and how far from tuned it is.
@@HomePerformance absolutely.
Looks like you have an "exterior" door separating your studio from the rest of the house. You've said elsewhere that they are separate systems. So how do you test in a situation like that? Unlike a bathroom or bedroom door, there's no gap unless you crack open the door, which obviously, impacts results. I've thought about putting the tube through a window and taping up the rest of the gap. Is there a better way? Also, how do you measure the air leakage between a home and attached garage? Since garages are leaky, I can't think of a set up that would separate leaks from the garage and leaks from outside. Thanks!
Hi. Always learn so much from you. I wanted to ask. I moved into a house that was build in 1962. There's a return vent in the basement. Is that normal and necessary? The main return is on first floor and no returns on the above floor. Also the return in the base, if I look through it about 10 feet across is the main return so wonder would my house perfom a bit better if I closed the basement one. I did a blower door test, horrible number at 15.7 ACH. My goal is to bring that down as much as I can. The second question is, what's a realistic goal for that loose of a house? Thank you.
Hey NYC, thanks for following. The basement return is certainly helping, and definitely not hurting. I’d leave it just as it is. And plenty of leaky homes in NY have been sealed 25-40% by the weatherization teams through NYSERDA, I’d start there. Bet there are some huge holes that would be simple to seal and get you way tighter in a matter of hours.
@@HomePerformance thank you very much for your response and help. I live in NJ, I need to change that name, lol. Any recommendation in NJ you like?
It’s a big state, but I have a few referrals, yes
@@HomePerformance I'm in the ocean county area, south central NJ, Toms River.
You can try Sanders Home Services, not sure what they’re up to these days but was impressed in 2016.
Would you generally recommend a central return for tight homes?
I do personally because you’ll have very little airflow into rooms in tight homes, but this topic does start fights.
@@HomePerformance thanks for the reply, any good videos or articles on this topic that you would recommend? I looked at your HVAC course but seems it isn't available yet
quality content, thank you!
Glad you enjoy it!
Riddle me this: what effect do you think continuous fan has on rh? Some people say it creates re evaporation problems but I theorize that it’s just HVAC induced infiltration
Good point, Paul. Could be both, but it certainly re-evaporates the water on the coil.
A lot of what is measured and tested is pretty much common sense. No expensive tools and excessive jargon needed. Human noses are pretty good at telling us if something isn’t right.
And forget about the pressures in the studio for the moment, the echo and lack of thought into the acoustics of the studio was completely overlooked and f’d up by whoever designed it. The echo is annoying.
Geez Mark, I have 3 kids. The sound baffles of Rockwool Comfortboard are not made yet. Only two walls in this room are equal size and parallel, I think we did a pretty good job actually.
@@HomePerformance Oh, I don’t think it’s the kids fault, but maybe perhaps the kids can help fix it? They should be able to cut comfort board,? I’m not sure about your neck of the woods, but a bag of comfortboard is way up in price.
Maybe it’s good for you to wait to complete the sound dampening. That’s a good idea though, what material do you wrap the comfortboard in?
Exactly what I needed. Thank you!
👍🏽👍🏽
Generally speaking. If you have the standard 1” bottom door gap, would cutting an additional inch off the bottom of the door (so 2” total) improve the airflow?
It would potentially double it
It might also increase the light and sounds that comes through the door, which isn't good for bedrooms. Corbett shows us that we can use the Manual D to calculate exactly how much of a gap we need.
@@peopleunite I recently living in a new build NV Home and the doors had a rather large 1.5" gap at the bottom of all the doors. Apparently this was by design (according to the builder) for improved return airflow. I can confirm it did improve airflow but it did have a downside of less privacy in the room.
I purchased a cps products spm-100 to do this room to main enclosure type testing, but am having problems with the product. It reads pascals to one decimal digit, the same as your tec tool displays. However, with the tool calibrated, and both ports open to atmosphere, I have a 5-7 pascal difference. I've tried rebooting the tool and recalibrating it more than enough times to rule that out as a variable. Could this variation be just because of the small, minute pressures we're trying to differentiate here, or did I just cheap out on my instrumentation? How does your tec dg-8 act with having both ports open to atmosphere (in a still environment, of course.)
The TEC and Retrotec manometers will show actual 0.0 Pa (fluctuating with breeze). That’s what you’re paying $600 per channel for.
@@HomePerformance thanks for the response! I'll get in touch w the company and hope for a return/upgrade.