Great video. Clear detailed explanation and example of where to measure static pressure. As an engineer, I was impressed with your use of fan laws for pressure drop. Great job!
Thank you sir! I train service and start up techs. I am going to make this video a requirement. Most techs do not even consider or think of static pressure. This definitely shows how important it is.
They are perfect for that as long as the hole in the inner wall is sealed with high temperature RTV. You can easily remove the plug the following year for testing. When you say "rated" however, there are no ratings for any type of sealant for b-vent that I know of. We do however have copies of letters from all of the major b-vent manufacturers on how the hole is to be sealed. You can email us or call us and we can get them to you via email if you need them.
Thanks. That was very informative. You put the static tip pointing up (with air flow) in blower section. In the diagram it is in blower section, reversed, pointing AGAINST air flow. Please clarify.
One nice thing you can do is use a perm magnet on the cabinet or plenum just below where you’re drilling to catch the drill filings when making the test holes.
One thing that might help is to cut a small piece of sheet metal and drill a hole in it and then tape it over the limit opening. you will have a removable port for static pressure readings. Also you can not suck or draw pressure you can only push it by the pressure difference.
I may be missing something, but aren't y'all in the business of actually selling meters, devices, tools, and equipment to tradesmen and the like? If so, I'm impressed. I can't tell you how often I've attempted to consult and extract info from a seller only to find they are completely clueless of the products they're selling. So this is refreshing.. Not sure what happened at the 11:40 mark, but this was a great tutorial.. I recently grabbed that Testo 510 to upgrade from my analog. It seems very accurate and stable, but I can't help wonder how durable it's going to be. It literally reminded me of one of those child's play plastic cell phones when I first handled it.. perhaps I just equate weight with quality, and next to my fluke with that big yellow cover, it just doesn't feel quite as durable, but perhaps and hopefully I'm missing something, and it will prove to be a great asset.. With all the choices you have a hand, I'm guessing you like it if it's the one you chose for this video..
Very good instructional video. Most of the systems I check are well above the recommended static pressure. I like the steel plugs- I am headed to trutech now for those. Good job.
The static pressure tip minimizes the impact of velocity pressure and turbulence in the duct providing a more accurate measurement. In a perfect world you could hold the tube at the face and read static, in actual application a static pressure tip is always recommended.
Very nice video thanks. I haven't found a video where one can make airflow measurements with hot wire given supply taps generally come few inches off of the duct connection to evaporator coil.
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 Thank you for this vid 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
Your installer should verify that the actual static pressures fall within the design range of the appliance and follow all of the manufacturer start up instructions/requirements included with the furnace.
great video on the understanding of how to uses digital anemometer to determine in-WC or in-Hg for you ac and heating system. But curious do you ever measure combustion chamber pressure to determine clogs or other obstructions in the combustion chamber not just for the return /supply vents. I would imagine you never want to drill into combustion because now you have CO possible issues in the future for aging systems. However maybe pulling off and using where the pressure switch goes into is one way.
You could, I am not a big fan of operating the furnace even temporarily without the limit, but I am a little conservative in that manner. However you make the measurement thought remember to test the appliance with the highest airflow requirement.
Do the heat exchangers have a pressure drop? If so I would imagine that pressure drop is counted for in the max esp on data plate? Now most limit switches are in between the heat exchangers not downstream, so if you measure esp there, aren't you going to get a reading that's a little higher because your not counting for 100% of heat exchanger pressure drop?
Hi, why is it necessary to do measure external static pressures? Is it a usual required measurement to be made in new installations? I have new system being installed, should I tell the installer to make these measurements? Thx.
It does not matter what way the tip points (up or down) as long as the shaft is parallel to the flow. What you do not want is the velocity pressure to influence the reading by impacting the pressure sensing ports.
Jim. Love your videos. Question. My company will not supply steel caps. Only plastic. Is it ok to remove the limit and just use some tape around your pitot tubes temporarily to get the readings? Then remove tape and reinstall limit? Just curious as to what your thoughts are. I am not comfortable with installing a plastic cap in that location. Keep the videos coming!
Great video presentation! I've got a question about your final comment that "static pressure is not a good way to quantify airflow". So even based against mfg specific-unit calculation charts you're saying those figures are not accurate enough?
one reason i can think of is lets say a motor is not running proper speed for what ever reason. If the air flow charts are based on a known motor performance/speed and that motor is only @ 50% the measured pressures produced will be lower.
Thanks a lot for your feedback. I am trying to get more done. It takes a lot of time. I am glad that you find them useful. Let me know if there are topics of interest that you would like us to cover.
Hi Jim, Great video, thanks. I may have room behind my furnace for drilling a hole, have close supply and return like yours, very tight. The high limit on my new Trane XT95 does not look like an easy pull out. How do I avoid drilling through something important on the back? Thanks, Paul
I'm confused, were you first using static pressure probes on the furnace (the ones with the closed tips)? And then you're describing a pitot tube (open tip) later in the video. I thought a pitot tube is used to figure out velocity pressure.
great video. thanks for upload. im here in canada and having a hard time finding these pitot tubes. i found one supplier that can get them in for me but sound expensive. 8" or 12" set for 120 dollars. any suggestions?
Have an airflow problem. 1.08 Tesp measured across RTU but, this 2 ton unit is just dribbling out air in the registers. Using a magnehelic, how do I identify where the obvious blockage is, or why air isn't screaming out the registers, not concerned with noise only the output throw of warm air.
Mike Malone you would need to start at the unit and take measurements periodically down the line until you see a big drop. In this case I would suspect a possible closed fire damper.
Honestly, What's the difference if you use a capture hood at SA or RA or Vane when CFMs and balancing is the concern............what is more accurate in you opinion..
@7:40, why do you say to put the tip in the direction of the airflow? I was told by more than one source to put the tip opposite the direction of airflow.
Gary Bonacci It does not matter what way the tip points as long as the shaft is parallel to the flow. What you do not want is the velocity pressure to influence the reading by impacting the pressure sensing ports.
I do not understand your calculating on you static pressure that you have it does not figure up right to me. 86,000-1.08x40=1990, or I am missing something. what I get 86,000-by 1.08x40=3185 help me under understand math.
Much easier to drill a hole in the duct between the filter and the furnace. I won't drill into an appliance if I don't have to. Obviously, no choice between evaporator and the furnace. Generally, an installation manual will call for a 6" riser between the furnace and the evaporator. When these are installed, taking measurements is a breeze.
Is there any downside of having unequal positive and negative pressures, even if they sum to 0.5? Seems 0.1 on supply and 0.4 on return would cause other issues.
Would it be a helpful measurement to merely put your hand in front of the farthest vent to see if the air is flowing freely? I would think that only if you were not satisfied with that air flow that you would want to go to the trouble and expense to measure upstream, no?
Nice video kind of misleading at the end with the comment made about not wanting to use tesp as an airflow measurement tool, this can be done just fine as long as you have the fan chart from the manufacure which uses these measurement figures to rate the airflow at different tesp's.
Don't think he'll get any manufacturer to agree that static pressure does not give you an accurate airflow. It tell you all you need to know about volume and velocity when you speak it's language, so to speak.
![[UNCUT]“ฅนตื่นธรรม”ปะทะ“หมอปลา-ปู่มหามุนี-อั๋นโอกิ”สะเทือนกระทรวงเวทมนตร์ Iคนดังนั่งเคลียร์I10 ตค.67](http://i.ytimg.com/vi/peMD_SAkwNc/mqdefault.jpg)
Great video. Clear detailed explanation and example of where to measure static pressure. As an engineer, I was impressed with your use of fan laws for pressure drop. Great job!
Thank you sir! I train service and start up techs. I am going to make this video a requirement. Most techs do not even consider or think of static pressure. This definitely shows how important it is.
this is one of the best videos I've found about this subject
They are perfect for that as long as the hole in the inner wall is sealed with high temperature RTV. You can easily remove the plug the following year for testing. When you say "rated" however, there are no ratings for any type of sealant for b-vent that I know of. We do however have copies of letters from all of the major b-vent manufacturers on how the hole is to be sealed. You can email us or call us and we can get them to you via email if you need them.
You have a great way of explaining things you need to keep adding more videos ASAP
Thanks. That was very informative.
You put the static tip pointing up (with air flow) in blower section.
In the diagram it is in blower section, reversed, pointing AGAINST air flow.
Please clarify.
He won't
11:42 - "Awwww Shit"- Pause..... then carries on. AWESOME!
One nice thing you can do is use a perm magnet on the cabinet or plenum just below where you’re drilling to catch the drill filings when making the test holes.
One thing that might help is to cut a small piece of sheet metal and drill a hole in it and then tape it over the limit opening. you will have a removable port for static pressure readings. Also you can not suck or draw pressure you can only push it by the pressure difference.
I may be missing something, but aren't y'all in the business of actually selling meters, devices, tools, and equipment to tradesmen and the like? If so, I'm impressed. I can't tell you how often I've attempted to consult and extract info from a seller only to find they are completely clueless of the products they're selling. So this is refreshing..
Not sure what happened at the 11:40 mark, but this was a great tutorial..
I recently grabbed that Testo 510 to upgrade from my analog. It seems very accurate and stable, but I can't help wonder how durable it's going to be. It literally reminded me of one of those child's play plastic cell phones when I first handled it.. perhaps I just equate weight with quality, and next to my fluke with that big yellow cover, it just doesn't feel quite as durable, but perhaps and hopefully I'm missing something, and it will prove to be a great asset..
With all the choices you have a hand, I'm guessing you like it if it's the one you chose for this video..
Very good instructional video. Most of the systems I check are well above the recommended static pressure. I like the steel plugs- I am headed to trutech now for those. Good job.
The static pressure tip minimizes the impact of velocity pressure and turbulence in the duct providing a more accurate measurement. In a perfect world you could hold the tube at the face and read static, in actual application a static pressure tip is always recommended.
Very nice video thanks. I haven't found a video where one can make airflow measurements with hot wire given supply taps generally come few inches off of the duct connection to evaporator coil.
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
Thank you for this vid
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
Very good teaching on The Measuring Total Estatic Pressure. Gwendolyn Greer
Your installer should verify that the actual static pressures fall within the design range of the appliance and follow all of the manufacturer start up instructions/requirements included with the furnace.
th-cam.com/video/k5GcI6cbL-U/w-d-xo.html Fucking lul my dudes...fucking lul.
great video on the understanding of how to uses digital anemometer to determine in-WC or in-Hg for you ac and heating system. But curious do you ever measure combustion chamber pressure to determine clogs or other obstructions in the combustion chamber not just for the return /supply vents. I would imagine you never want to drill into combustion because now you have CO possible issues in the future for aging systems. However maybe pulling off and using where the pressure switch goes into is one way.
Love the video thank you for all the great helpful information keep them great videos coming 👍🏻
One of the best explanations I have seen.
You could, I am not a big fan of operating the furnace even temporarily without the limit, but I am a little conservative in that manner. However you make the measurement thought remember to test the appliance with the highest airflow requirement.
Do the heat exchangers have a pressure drop? If so I would imagine that pressure drop is counted for in the max esp on data plate? Now most limit switches are in between the heat exchangers not downstream, so if you measure esp there, aren't you going to get a reading that's a little higher because your not counting for 100% of heat exchanger pressure drop?
I liked that 3D sketch of thee pitot tube. I’ve never seen that before.
Your tip is supposed to go in the direction against the air flow. So if the airflow is flowing up then you want to point your tip down.
Am i wrong?
Hi, why is it necessary to do measure external static pressures? Is it a usual required measurement to be made in new installations? I have new system being installed, should I tell the installer to make these measurements? Thx.
It does not matter what way the tip points (up or down) as long as the shaft is parallel to the flow. What you do not want is the velocity pressure to influence the reading by impacting the pressure sensing ports.
Thank-you all for the positive comments.
Jim. Love your videos. Question. My company will not supply steel caps. Only plastic. Is it ok to remove the limit and just use some tape around your pitot tubes temporarily to get the readings? Then remove tape and reinstall limit? Just curious as to what your thoughts are. I am not comfortable with installing a plastic cap in that location. Keep the videos coming!
Are the steel plugs rated for testing b vent?
Change That Dull Drill Bit !! Great Video !!
Great video presentation! I've got a question about your final comment that "static pressure is not a good way to quantify airflow". So even based against mfg specific-unit calculation charts you're saying those figures are not accurate enough?
Good question, idk why the guy ignored u
Staying within spec design keeps you from robbing Peter to pay Paul and have a balanced , quiet flow of air ...
one reason i can think of is lets say a motor is not running proper speed for what ever reason. If the air flow charts are based on a known motor performance/speed and that motor is only @ 50% the measured pressures produced will be lower.
Very Good Video,That’s for Explaining and being detailed about Static Pressure on Furnace..... Could you do the Hot Wire Anemometer Test Also plz....?
Your explanation is very clear .Thanks
Thanks a lot for your feedback. I am trying to get more done. It takes a lot of time. I am glad that you find them useful. Let me know if there are topics of interest that you would like us to cover.
TruTech Tools, LTD very helpful and well explained. Thanks for posting this stuff!
Hi Jim, Great video, thanks. I may have room behind my furnace for drilling a hole, have close supply and return like yours, very tight. The high limit on my new Trane XT95 does not look like an easy pull out. How do I avoid drilling through something important on the back? Thanks, Paul
Drill in the back top center
Static pressure tips provide a much more accurate reading as they are not subject to as much influence of velocity pressure in the duct system.
Great video Jim. Very informative.
Hey, I've a cross flow over finned tube heat exchanger inside duct, which type of pressure should I measure static or dynamic.
Does the same testing rules apply for a heat pump system? I would presume so, but most of the information I see online refers only to furnaces.
Yes, all of the same rules apply.
Heatpumps are calculated for ac airflow..single stage..then cfm increases if additional btus or stages are added.
Excellent training
I'm confused, were you first using static pressure probes on the furnace (the ones with the closed tips)? And then you're describing a pitot tube (open tip) later in the video. I thought a pitot tube is used to figure out velocity pressure.
pawelkoper Correct, he is just explaining both
great tutorial. fantastic job on presentation!
very good presentation! lots of useable info. thanks
great video. thanks for upload. im here in canada and having a hard time finding these pitot tubes. i found one supplier that can get them in for me but sound expensive. 8" or 12" set for 120 dollars. any suggestions?
very nice video
very nice video
very nice video
Have an airflow problem. 1.08 Tesp measured across RTU but, this 2 ton unit is just dribbling out air in the registers. Using a magnehelic, how do I identify where the obvious blockage is, or why air isn't screaming out the registers, not concerned with noise only the output throw of warm air.
Mike Malone you would need to start at the unit and take measurements periodically down the line until you see a big drop. In this case I would suspect a possible closed fire damper.
thanks for your input...
Honestly, What's the difference if you use a capture hood at SA or RA or Vane when CFMs and balancing is the concern............what is more accurate in you opinion..
Thank you so much.
@7:40, why do you say to put the tip in the direction of the airflow? I was told by more than one source to put the tip opposite the direction of airflow.
Gary Bonacci It does not matter what way the tip points as long as the shaft is parallel to the flow. What you do not want is the velocity pressure to influence the reading by impacting the pressure sensing ports.
Gary Bonacci we also have a short illustration at the following link under the “Resources” tab : www.trutechtools.com/SPTK
I do not understand your calculating on you static pressure that you have it does not figure up right to me. 86,000-1.08x40=1990, or I am missing something. what I get 86,000-by 1.08x40=3185 help me under understand math.
Very informative, thanks for posting.
I thought the tube is pointed into the airflow.
Yeah that’s what I thought too. You want the air to hit the tube.
for static pressure no
Much easier to drill a hole in the duct between the filter and the furnace. I won't drill into an appliance if I don't have to. Obviously, no choice between evaporator and the furnace. Generally, an installation manual will call for a 6" riser between the furnace and the evaporator. When these are installed, taking measurements is a breeze.
wow great vid right off the batt!
Is there any downside of having unequal positive and negative pressures, even if they sum to 0.5? Seems 0.1 on supply and 0.4 on return would cause other issues.
That would indicate an imbalance in restriction, indicating more return flow is needed.
Great video as always. Thank you.
Very informative, Thank you!
Great video keep them coming
Would it be a helpful measurement to merely put your hand in front of the farthest vent to see if the air is flowing freely? I would think that only if you were not satisfied with that air flow that you would want to go to the trouble and expense to measure upstream, no?
11:38 lmao! That's the good stuff!
Chris Diaz lol he just moves on
Thanks so much.
I was laughing out loud after 11:38 .... Great video by the way
11:30 - 11:45 cracks me up! lol
DUSTIN EHRLICH that's funny lol
Was Brian O behind camera? Lol
Very helpful.
Thanks
Nice video kind of misleading at the end with the comment made about not wanting to use tesp as an airflow measurement tool, this can be done just fine as long as you have the fan chart from the manufacure which uses these measurement figures to rate the airflow at different tesp's.
Thanks, I will send you an email at trutech. Thanks for the quick reply.
Thanks 🙏🏼 nice 👍
Don't think he'll get any manufacturer to agree that static pressure does not give you an accurate airflow. It tell you all you need to know about volume and velocity when you speak it's language, so to speak.
11.45 oh yesss
Oh sh#t lol
нужен перевод на русский
He put his tips the wrong way. ALWAYS point the "bullet" tip point toward the air.
no hes right. he only want to find out static pressure so doesnt matter which way it point. other way for reading static and total velocity