Tech Tips: Static Pressure Testing

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[@strunkmp]

The best explanation of measuring duct static pressure out there. And I have watched them all. Thanks

[@abledistributors]

Thank You ! please stay tuned, more fun videos like this coming, hope you check out some of our other videos, stay well.... Brian

[@martinheatingcoolingmartin4693]

Excellent explanation! I will need to rewatch several times though for it to sink in. But seriously thank you! Because as others have said, this is the best out there to do with static pressure.

[@tommason5689]

I was most concerned about the coil drop since cleaning the A coil is a huge job. And I would like to share what I have done to measure the coil drop, which is very easy to do. You do not need to drill anything and you do not need to buy the special probe either. Just use the screw hole by taking out a screw. To measure underside of the A coil, I unscrewed one of the easily accessible screws from the triangular A coil cover blocking the underside. To measure the top side of A coil, I unscrewed one of the A coil housing cover screws and measured there. In both cases, I pressed the open end of tubing from the manometer ($35 from Amazon) right against the screw hole tight and read the meter. In my case, I measured 0.16 (top side) and 0.25 (underside) which gives me drop of 0.09 WC. I was afraid my A coil would be clogged up a lot after 26 years of use without cleaning at all but this measurement tells me it is wide open for which I am so happy not having to do the big job of disassembling the whole A coil and cleaning it up and reassembling it. Just for sanity check, I also bought Anemometer ($16) from Amazon and it measured anywhere from 550-800 ft/m air speed out of all the vents which seem very reasonable based on what others measured on brand new system. This sort of confirms that my A coil is pretty clean even after 26 years of use without cleaning at all, which is quite surprising. I did not even replace the filter either. I simply vacuumed the filter every year. I hope I am not dreaming.

[@thomasjohnson3452]

Before drilling holes into your furnace....see if you can unscrew the heat exchanger high limit switch for TESP probe access.

[@crazy8051controller]

This is an amazing explanation. Really helpful. Thank you so much

[@StepehenA]

Nice job Brian. Good review of the basics. - American Weathermakers

[@briandaleske9140]

thank you, more to come.

[@davidjensen4654]

Great explanation of static pressure and ductwork design. Very helpful for a GC superintendent. Thanks

[@abledistributors]

Thank You ! more to come, working on more videos this week.. Brian,

[@gabrielm9391]

Man great video! It all became so clear to me after watching this. Thank you for such a great explanation and keeping it short and simple

[@abledistributors]

Thanks for checking out the video, I've got a million ideas for videos, just need more time, stay tuned more on their way ... Brian,

[@ericviele4379]

Yep, best explanation out there. You got a like and a subscriber. Great content!

[@abledistributors]

Thank you ! more videos coming soon, I don't script these, I draw on my board, and just start the camera, so for me I need to be in the mindset to shoot a video.... thanks again for checking it out. Brian,

[@Tito-hvac8]

Great explanation!

[@abledistributors]

Thank You, on my list is a few more duct work videos, please stay tuned, more videos soon. Brian..

[@Gabriel-vz7ml]

Thank you.

[@abledistributors]

I'm working today on some new videos, so keep checking in, more on tools and procedures .. thanks for checking out our videos !

[@tech2tech672]

part two is up now

[@rtsolution11]

I am fighting my system currently which is what brought me here. I purchased a nice set of field piece wireless probes. I am upwards of .89 tesp with the majority in my return duct. .12 in my supply, .21 a coil, .10 filter, remainder is supply ductwork.

[@jakebrown3769]

Great video

[@briandaleske9140]

Thank you so much, we have a lot more videos coming soon, stay tuned.

[@tech2tech672]

Part two is up now..

[@abledistributors]

new video up now, duct sizing made simple, check it out..

[@coolramone]

4 probes: A. Top of heat exchanger (box), B. Bottom of blower fan (box), C. Top of coil (box), D. Before Filter.

[@chrisbouse4266]

Great video very knowledgeable

[@abledistributors]

thank you, working on new videos, keep watch

[@tech2tech672]

part two up now

[@abledistributors]

new video up now, duct sizing made easy, check it out..

[@tgriebe]

Excellent

[@abledistributors]

Thank You, working on more videos, some diagnostic , some installation... stay tuned.

[@peterrivas08]

Could it have also been a problem with supply blower? Weak motor or wrong blower speed?

[@abledistributors]

actually if the blower wheel was dirty ( dirt packed in the blades ) the blower would move less air, and the static pressure would be lower, also if I had lowered the blower speed, it would have decreased the static pressure. static pressure builds when we try to move air through restricted duct work. in my experience most causes air a very dense filter media, not enough return duct or return openings, a dirty A-coil... those are what I usually find.

[@abledistributors]

Part Two is up on our channel now.

[@willpartin622]

Thank you for all your great vids. I was wondering if you can ever have too much return ducting. After watching your videos, I checked my external static and found 3.5 and 3.5 for a total of 7 in WC . Filter drop is .18 INWC ( 5 inch air bear) and a\c coil drop is .21INWC. ( 2.5 ton N coil.) The temp rise is 70 degrees in heat mode. Rheem says 40-70 rise is okay , so I'm at the high end of acceptable . Shooting for 55 degree rise. I'm thinking I might need more returns and supplies but don't want to over duct it. Any help or advice? Also, when is was installed they added one 10' and one 8 inch flexible return duct. this is a 70,000 BTU Rheem 95% that replaced a 115,000 Ruud 95% furnace. Thank you Reply

[@abledistributors]

your temp rise is a bit high, your correct 55 or 60 would be much better. the N-coils do have more restriction. I don't think you need to worry about too much return, you might be able to get better performance by taking the Flex Duct returns and running them in hard pipe. I've never had a system be perfectly balanced like you have ( both the supply side and return side have same TSP.

[@chodkowski01]

Look at the filter the engineers design and test their air conditioners with. They use the very light blue filters. Using a filter with a high merv rating causes your fan to use more amperage, running hotter and cutting down its life expectancy and cutting down air flow.

[@abledistributors]

YES... I have a video on our channel all about filters, fiberglass to pleated and how they changed airflow. thanks for checking out our videos, Brian.

[@rickgonzalez3662]

So what is the alternative running a fiberglass 1 inch filter that doesn’t catch any particles they’re useless so you pick your poison and you use a pleated filter

[@abledistributors]

@@rickgonzalez3662 remember the filters were never intended to clean the air in your home, they were originally added to protect the equipment from getting blocked up, protect the blower wheel and the AC coil... there are options from Honeywell, Generalaire, and AprilAire , these are super wide filters, some as wide as 7", these would be a much better choice in my mind, of course these need to be professionally installed, but your correct, in the end, we all make a decision.

[@johnwhite2576]

Isn’t it preferable to have more of your total external static on supply side for velocity and throw?

[@nelsonflores67]

Great video, question how do you calculate, or where can i get the info when the sp is higher? How less of cfm and temp rise will get?

[@abledistributors]

most brands either in the set up instructions or even inside the blower door, there will be a chart showing you the blower speeds and how many CFMs will be at different static pressures, and some will include the temp rise at that speed and static. hope this helps, stay tuned, much more coming.... Brian

[@JohnnyJr396]

Thanks for this. Is it true that TESP will get you in the ballpark for blower speed settings but you’ll need other tools to test capacity and actual cfm?

[@abledistributors]

testing your total static will just let you know how well your duct work is performing, knowing this will give you an idea of where to start. actual CFM is a different measurement, I will be coming out with future videos on how to measure CFMs and simple temp rise blower adjustment. I did this video because as we get into more advance modulating equipment, like the Bosch IDS, airflow is very important, more videos coming soon.

[@JohnnyJr396]

@@abledistributors Thanks! Is it safe to assume I can have the right CFMs and have too high TESP causing more work on the blower and noisy air from duct? So TESP is still a relevant test other than finding blower speed setting?

[@famousdude1239]

Doesn't a step bit let metal cuttings drop into the furnace and into the fan motor windings?

[@tommeyers974]

Nice work on the video! I am confused by my bypass humidifier. Any thoughts? Thanks. Tom

[@abledistributors]

just my thoughts on a bypass humidifier.... if your duct work is adequate ( you have plenty of supply and return ) you "should be fine" but if your home is like many, where they're just short on return, you'll end up bring much more air through that bypass than you would want. temp rise with the bypass damper open VS. closed may indicate how your system is working. I would check your static with bypass damper closed. I don't know if I helped or hurt with your question.

[@tommeyers974]

TNX. My manometer and probes come tomorrow. I shall measure everything every which way. Then I'll know more.!!

[@rodlasher8478]

Is a good rule of thumb for static filter drop of .5 differential a good indicator to change your filter

[@michaelfassino4314]

Help please. My static is hi and the issue is with return side. Can I add return air to the other side of the furnace to make a dramatic effect and get that static number down ? Thanks for helping !!! Mike

[@abledistributors]

yes you can always do dual sided return, on some larger furnaces it's recommended by the manufacturer , remember you would need to add another filter to that side, and always get return air from the living space and not from the mechanical room or unfinished basement. when I'm searching for the issue, I look at the entire return duct system, from the duct size to how many returns are taken off that duct, adding return is always a good thing, finding where in your home you can put that new return is often the problem, I would never just cut a hole in the duct work, pipe it someplace, even if it's in the floor. good luck, hope this helped a bit. Brian

[@michaelfassino4314]

@@abledistributors thank you !! And yes I will have the other side adapting to a joist space and terminate to a floor grille with large openings and the filter for this will be at the furnace. One more Question if I may All my in the wall return grilles are up high on the 9’ wall Do you think that causes restriction too much compared to grilles close to the floor ? Mine are 6x14 with 1/3 fin spacing and there are 9 of them and I want 1000 cfm (2.5) ton ac and 92% 60k furnace

[@michaelfassino4314]

A little more info if you would like. My one return drop is a 10x20 with 16x20 x1” filter which I’m switching to fiberglass but my return static is .4. On the supply side I have a “n” style coil and good size ducting and supplies for 2.5 ton

[@jaysims7983]

Thanks for a great video. Do you conduct the test in heat mode or just fan mode? Temperature will affect TESP. Correct?

[@abledistributors]

typically I would have it on the highest speed, ( on heating speed I usually check temp rise )

[@jaysims7983]

@@abledistributors Thanks for your response. However, I am still not 100% clear. Should I have the thermostat in heating mode or simply run the fan to test TESP?

[@abledistributors]

@@jaysims7983 sorry, yes fan on would be great, make sure all the supply registers are open, clean filter, check if you have supply dampers in your supply ducts, make sure they are open, if you have a bypass style humidifier, make sure that damper is closed. last thing is to check return grills to make sure they are free from anything blocking them. so yes, thermostat to off ( no heat or AC ) fan mode to On.

[@CC-ew2jw]

Could you pull the disconnect on the compressor and put the thermostat in the AC mode to get the highest fan speed?

[@pauln4dmeedwards775]

WELL GET YA MATH RIGHT A IS -.22 + .39 = .17 NOT 61

[@abledistributors]

when your calculating total static pressure, you add the two results, even if one is a negative number, because the amount of suction needed and the amount of built up pressure both equal the total static pressure, I'll re-watch this video to make sure I mentioned that. but thank you for checking out the video, stay tuned, much more to come.. enjoy your day, Brian.

[@fernandorosillocorrales6331]

- just means suction, + just means supply. Just have to add both results.

[@will-smith-nh]

Excellent

[@abledistributors]

thanks for the comment and thanks for checking out our videos, work has been crazy, but more videos coming.