Craig, since I’ve seen very little comments about it, I’d like to mention also that some brands of furnace the secondary heat exchanger is another place that gets clogged up and is often overlooked.
Best video's on the internet for Hvac. I've been watching them for years and still learning and relearning daily. Thanks for making this happen. Well done.
Having 58 rental units to contractually care for I have become quite proficient at in unit coil cleaning. Renters tend to remove filters instead of replacing them. I have developed my own system for cleaning furnace "A" coils in system when possible. An expandable V shaped water and dirt collector of my own design is installed below the coil and a shop vac attached. I use the red acidic type cleaner with a carpet blower providing fresh air to me. I wear safety goggles and a face shield along with charcoal respirator. (I learned the hard way) I scrape away as much as I can, spray the coil then rinse. Repeating as necessary, often 4 to 6 times. Then when its clean enough I rinse til I am sure it's not acidic then I am halfway done rinsing and rinse it a few more times. If the coil box is too close to the heat exchanger I remove the coil the old fashioned way and clean it outside but I can do many of them without removing it to great success. After 10 years of working on the same units I have not had any problems. Only 1 blower motor failed early on because I failed to cover it correctly but no coil thinning or leaks.
thank you. I'm doing a career change into HVAC and the books can be really boring and hard to take the info. these videos have been a great way to re enforce my knowledge. thank you and please make more content!
Informative video. Pulling those A-coils for the purposes of cleaning the inlet side of the coil is labor intense and, therefore, time consuming. Once it's out, cleaning both sides should be done.
I mean, I do have that very manometer. And it's really good. But I rarely use it when dealing with airflow issues. I just make it a habit to check coils, even hard to reach ones. A poorly performing system can have many reasons behind it, but it doesn't take too much effort to look at the coil. I have my light, drill, and a good brush typically get the job done. And a lot of elbow grease. Sometimes I'll use a shop vac or something. A brush usually removes those wool sweaters. But I really do like this systematic approach. Very thorough.
Good stuff even though I've been out in the field almost 30 years it's always good to focus on the stuff we might overlook at times when we get too many calls dumped on a great video again always
Unfortunately I happen to have a York unit similar to what you showed with the evap coil above the furnace. Any chance you have a video that’s more step by step on how you clean unshroud and clean a coil in that situation with without disconnecting the line set?
Taking static pressure seems to be an unnecessary step for this troubleshooting example. Wouldn't it just be easier to pull back that coil plate and look with a flashlight? What other ways would static pressure be utilized? Would undersized/oversized duct work cause this problem? How would you accurately address it? Thanks for another good video!
Drilling a couple small holes is much quicker than taking apart a coil compartment. And if he’d have not gotten such lower pressure above the coil he could easily have kept moving through the ductwork. There are many possibilities for high pressure (insulation coming loose inside ductwork or vents that are closed). As far as ductwork undersized your only option is to change it. At least the first few sections until you have some vents relieving the pressure.
If the back of the furnace is open to service ( not to common ) the back of the Evaporator coil doesn't have the line set or metering device or distribution tubes in the way. Be very careful cutting open the sheet metal not to hit the U tubes on the back side of the coil. Also found out not to hit coil with screws attaching new cover.
Great video. Would you elaborate for me I’m a little confused.. Do you not subtract the (-.21) from the (+.87) giving you (+.66)? And would you explain why?
He is determining the total pressure drop across the evap coil. Pressure entering the coil is + 0.87" w.c. Pressure on the downstream side of coil is + .021"w.c. So the pressure drop or restriction value of the coil is +0.87 minus +0.21 leaving + 0.66"w.c. of resistance to airflow.
This is still all really confusing. I thought static was air resistance. Why does the meter show a minus number at the return and a positive number at the supply, how does the meter know the air is sucking or blowing with just a rod with some holes in it stuck in there? I thought total external static measurements was a measurement at the return and a measurement in the supply.. not a measurement inside the furnace. : T
