Gas Furnace Class
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- Опубликовано: 17 июн 2024
- Bryan teaches the Kalos techs a Gas Furnace Class. He covers many types of furnaces, especially 80% gas furnaces in Florida. They also talk about furnace troubleshooting, maintenance and do some hands-on training at the end.
Furnaces use a flame, or the rapid oxidation of fuel, to heat the air. The furnace achieves combustion with a heat source, fuel, and oxygen. Furnaces may use one of two main fuel types: natural gas and LP (liquefied petroleum). Propane and butane are heavier than natural gas, so they are more dangerous because they displace oxygen and fill the room from the bottom up.
The furnace sequence of operation starts with a W call, which is a 24v call for heat on the W terminal (white wire). You don't want a G call because the fan would circulate cold air before the furnace lights, and we want to observe the flame before and after the blower starts. The flame should stay straight; if the flame wiggles a lot, you could have air leakage. Another potential cause of a wiggly flame is a cracked heat exchanger (which is quite uncommon in Florida).
After the furnace receives a W call, the circuit board will check the inducer fan; under typical conditions, the inducer fan will start. (The inducer fan typically uses a shaded-pole motor.) Then, the pressure switch ensures that you have a proper draft. The pressure switch must have sufficient negative pressure in an 80% furnace.
When you have a proper draft, you start the ignition sequence. After ignition, the gas valve opens. A flame rod or flame rectifier would prove that the flame is burning; if the flame is not burning, unspent gas could build up and cause an explosion. After everything has been proven, the blower will start up and move heat through. If any safeties can't prove air or flame, the furnace will shut off.
We use four main types of ignition: standing pilot, direct spark (DS), intermittent spark (ISI), and hot surface (HSI). Standing pilot ignition requires us to light the pilot, and a thermocouple proves flame on the pilot light. Direct spark uses a spark to light the main burner. Intermittent spark ignition relies on a pilot that is NOT lit all the time; the spark igniter can also sense flame. The most common ignition type is hot surface ignition, which relies on a rod that heats up. Hot surface igniters are common fail items. The gas valve opens and puts gas in the main burner.
When a furnace goes out on rollout, the rollout switches will open. High limit switches trip when the furnace gets too hot, which usually indicates low airflow.
Natural-draft furnaces aren't very common in our Central Florida market, but we often see 80% non-condensing open combustion induced draft furnaces. The latter pulls air in from around the unit in the combustion air zone, so these units can't be stuffed in closets.
The biggest dangers of gas furnaces are gas leaks, carbon monoxide, and flame rollout. Low-level carbon monoxide detectors can pick up carbon dioxide, and we recommend offering them to all of our customers who have gas furnaces.
We prioritize safety over efficiency in our market, so we try to look for improper venting, poor gas line insulation (or other gas line leak risks), backdrafting or orphaned water heaters, improper gas pressure settings, high ambient CO during operation, CO in the home, and improper combustion air.
Useful tools for working on gas furnaces include combustion analyzers, low-level CO detectors, combustible gas leak detectors, and manometers. You'll want to use your manometers to be aware of gas pressure and static pressure. You will use your manometer to set gas pressure (inlet AND outlet pressure), your personal CO monitor to measure ambient CO, and your combustible gas leak detector to check for leaks.
You'll put your visual inspection skills to use on gas furnaces, checking for corrosion and other abnormalities. Check the surrounding areas too.
When servicing gas furnaces in Central Florida, we start by checking and cleaning the burners. Then, we check existing CO monitors and advise customers about low-level CO monitors. We then inspect and clean the flame rod/sensor. After that, we inspect the venting and combustion air and check for gas leaks or improper piping. Then, we actually run the system and check the flame during operation. We then measure CO and gas pressure. We finally check the temperature rise.
Bryan also covers:
Fuel concentration
Proving inducer air
Pressure in the flue
Gas pool heater ignition
Gemini gas valves
Inducer fan motor issues
Venting for high-efficiency furnaces
Testing a flame rod/sensor
Adjusting Gas Pressure on a Standard and Gemini Furnace Valve video: • Adjusting Gas Pressure...
#Bertlife Gas Leak video: • Adjusting Gas Pressure...
Read all the tech tips, take the quizzes, and find our handy calculators at www.hvacrschool.com/.
Learn more about the 2022 HVACR Training Symposium at hvacrschool.com/symposium/.
“What is the oxygen % in the air?” Uhh 150%? Lol priceless. I’m the only person who watch this for it’s comedic value. Nice informative class ether way.
As an HVACR Instructor, i get all kinds of answers from students.. hard to stay professional and not laugh at some... yes, great videos still.. keep them coming Bryan!!
@@wickylopez8867 I too have had the pleasure of instructing and I wouldn’t consider laughing at any answer. Thankfully I’m a spectator on this one and I can laugh. 😝
Professor joe ward 👍
Около о горло о ооогооооогогтооооооугу от топ и ооооооот аз ооо
Ah don’t be mean. The lad that asked that question might be a top notch contractor now :)
You have got to be the nicest person I have seen teaching . If I was teaching that class and my guys were spending a good portion of time looking and texting on their phone I would just ask them to leave if that was more important !!!
100% Agree. The future is clearly uncertain in regards to the trade. How long will mr purple last after 5 years of real world work?
He’s taking notes on the notepad phone app 🤤 duh....
@@S_a_n22 Mr. Purple is acting like the senior techs or 'old timers' that I know.
@@rayzerot agreed. that attitude rubs off on many in classes. Imho.
Dude. I've seen your videos for 3 years. Your fan coil, Ac, airflow, etc.stuff is, humbly, on point. I work in OH, your gas furnace skills need sharpening. You're mixing 101 lessons with master's classes here. Start with the order of operations.
I would argue that he is trying to overview gas furnaces, and fill the gaps in knowledge for relatively experienced techs. Just because something seems 101 to one person, that does not mean that it was taught to another person. I already knew a lot of the stuff he went over, but it was still supremely educational.
@@jonahlee1272, I agree. I learned a lot about gas furnaces from watching this video. Brian definitely knows his sh... um, stuff. He may/may not be a professional when it comes to gas furnaces, but I really enjoy his method of teaching nonetheless.
We all take in information through our five senses, and each person takes in information a lot easier when being taught from a certain perspective than someone else who could be sitting in that same classroom.
I guess what I'm trying to say is that you may think that someone's way of teaching may/may not be 'the right way'. But that same method of instruction may actually turn out to be the one way that, after watching countless RUclips videos online (and still not understanding what it is that someone is trying to learn), they finally see everything much more clearer after being taught the way that you disapproved of.
For me personally it's a big pleasure to watch Brian's videos. I am not a native English speaker, and despite he speaks very fluently - I can understand every word and idea. I've watched many of his videos. And even having more than 20 years of Marine ET experience, dealing with many kinds and types of HVACR equipment - some of my blind spots I've filled here (have to clarify that I had no HVACR course in Academy while studying, so I'm a self-taught in this field of knowledge). Thanks to Brian. Will continue following.
I enjoyed this video very much. I started out as an installer at the age of 17 in Texas. Became a technician a few years after. Now I mainly work on MUA systems, chillers and boiler systems for industrial applications. Which started around 25 years of age. Now I’m 29 and I can damn near work on anything hvacr related from residential to industrial. It’s always nice to be reminded of the basics. I’m a recent subscriber and I always enjoy watching your videos! Thank you.
The guy in the purple jacket is pissing me off. They should be taking these classes seriously. I work in central Florida, and I would trade ALOT to have trainings like this. All these guys need to pay attention and really ask good questions. YOU GUYS HAVE SUCH A GOOD TEACHER something my boss rarely did.
This was a very helpful and thorough presentation of gas furnace servicing.
I recently remove the black wheel and me draft inducer motor and oiled the bearings so the person would not need to spend $400 on a new motor plus labor. It would squeak at times so I figured the bearings were getting dry. The fence inside the black wheel which had an open center were full of oily dust. I cleaned the fence off and wondered if this black wheel was also intended to be a cooling fan for the shaded pole motor. Normally I would not count on oil light type bearings to keep running after being oiled for very long. This type of motor has some packing around the bearing which holds oil so I expect it to last. When I started servicing HVAC equipment in a rather wealthy neighborhood on the north shore of Chicago there a many antique Boilers around still in 1984. We had to replace the thermal couple on each service call for a gas burner. It was interesting hearing you refer to these items as being unusual nowadays. The fan limit switch that started and stopped the blower motor was very common. One place I worked in the 80’s for 22 years had a dual section boiler that was the old style. It had metal doors that could swing open around the burners and they were getting disintegrated by flame rollout. I learned that they had some thing like a 6 foot run horizontally of the flue pipe within the building itself. I don’t know if they ever change the boilers but there was some concentration of CO2 around the burners because the draft was not adequate. I feel more prepared to look at home furnaces after your video today. I was involved on a regular basis with maintaining a complete steam heating system including overhauling the 200 hp boilers, pumps, piping & over 400 steam traps. With my electronics background I was asked to re-wire one of the 1968 Boilers which had vacuum tubes in its controller. I had to convert it to a Fire- eye digital controller. I was able to do that but made one mistake that started to show up 20 years later. The boilers should have been wired for purging on high fire instead of low fire. The state inspectors discovered this mistake and it was probably the cause of an internal boiler explosion.
I made that choice based on what a previous electrical engineer had done with the other boiler that he had converted to a Fire eye controller. I also learned that if I had a license at the time I would have lost it for installing a new Honeywell actuator on the main gas valve.
Neither boiler had redundant gas valves as a safety measure and they were grandfathered in. It would have been a tremendous expense to redo the piping because those gas lines were roughly 4 inches in diameter. Another time the bother would not start because a spider have built a web over the vent for the big regulator on the main gas line. Your video was so comprehensive that it made me feel more up-to-date on the current high-efficiency boilers.
Thank you very much for all this information.
The class participation was also very helpful.
Stuart Milne
I actually watched this the whole way thru… very informative and well done. Thanks for providing this valuable resource!
Electronic only furnace requiring a G call got me before! Blower motor wasn’t coming on, no G call from thermostat during heat.
Changed settings on thermostat for electric heat. Thermostat then called for G during heat. System then worked fine after that! Thank you.
"Joe Becker, what a fancy boy"
This is half the reason why I watch your classes XD
The pressure switch they brought up thinking you can just leave it jumpered would be on the Amana/Goodman/Daikin high efficiency furnaces. They have a pressure switch they label as a plugged drain pressure switch. This switch is wired inline with the gas valve. It will never produce a pressure switch fault but will cause failed ignition faults.
Ain't no way the big burly fella in the front on the right said "Transformers - ROLLOUT!" 🤣🤣🤣🤣🤣
That was only my FAVORITE CARTOON OF ALL TIME growing up! 😂
Awesome video. I learned some stuff, for sure. Thanks! Looking forward to more school classes.
Ain't no way the big burly fella in the front on the right (@ 32:38) said "Transformers - ROLLOUT!" 🤣🤣🤣🤣🤣
That was only my FAVORITE CARTOON OF ALL TIME growing up! 😂
Great video 👍 paid 10 grand for a hvac school and I had a hard time understanding everything but I did 3 years on the field experience. Thought about re doing the whole hvac course just to get a better understanding of the whole hvac system in depth but haven’t heard from the school and to be honest that’s okay with me because your videos are just awesome. Thank you so much
Honestly, I've learned more on my personal time researching than being in college.
Who needs to pay for an HVACR school when we got Brian?... 😆
Just kidding. I'm actually in school now learning about this new passion of mine.
Came across Brian's videos and didn't hesitate to 'smash that Like button and subscribe'! 😏
Great class. Very informative Thanks
What’s another reason why a flame would be moving besides a leaking heat exchanger? “Good music” Nathan Orr 2021. You sir are one of the greats! Thank you for your contributions to the trade!
Great job on the training class!
0p0
nice to see other perspectives
It was an amazing class congratulates
Not only do you need classes like this you also need written classes to make sure these people know there stuff.
Enjoyed the video, very informative. Your techs don’t have to deal with issues such as snow/ice in the vents or frozen condensate drains that we do here up north. Send some of them to Craig M. for the winter😂
Thanks again 👍
Very good a patient teacher. I can't believe the apparent apathy of his "students", however. I would have long-ago yanked the cell phone out of the hand of the guy on the right. Sorry for the negativity,. Good video
Good training class.
Just a side note. There are no high-efficiency furnaces that will start with a pressure switch in the closed position. I am a gas technician in Ontario and I have never seen a pressure switch start in the closed position.
The guy didn't know what he was talking about. Thats why he's in Florida lol
Great information ❤️
Goodman has a pressure switch in line with gas valves that can be jumped out, always 2 gray wires. And the dual p switches for high and low fire that can not be jumped out.
No brand lets you jump it out, unless after the inducer starts. You are correct Brian
Great video
The reason you got the limit code at the end was because you shut the power off while the burners were on therefore the blower didn’t cool the heat exchanger down and overheated the limit.
See alot of green beans doing this and I always give them sh*t . Hit the gas cock count to 20 open it then pull power lol not hard
Man I would love to sit in that class!
Informative video 👍
this is a really good video. If you take the time to watch it and listen you will learn
September 1 was pilot season, and as far as I know it still is.(philthydelphia Gas Works)😂
Thanks for the videos.
🥃🥃🍺🍺🍺🎯🏌🏻♀️
Stay safe.
Retired (werk'n)keyboard super tech. Wear your safety glasses!
Thanks !
You are a good teacher Bryan. As for the students, I'll be nice and assume that the guy texting has a wife who just went into labor.
Some furnaces like mine have two series pressure switches. If you jumped one out the circuit is still open as long as the other switch is working. Then when the switch makes the circuit closes. Not advocating for jumping switches out but sometimes if it’s two in series and one is an issue and you jump across the one that doesn’t make it would still fire.
For best results TAP 1:10:49 repeatedly
great info i love it
nice video!!
Can’t wait
Thats crazy where in Winnipeg Manitoba Canada and some are 96 aflu my new one is but we hit -40C. We have a house in Florida but it's newer and has a heat pump
The best type of ignition system is DSI. I have NEVER had to replace a DSI rod. This is why I am a Ruud dealer and only install their systems.
In a restaurant had problems with a 50 gallon commercial water heater. Ended up when building was all doors and windows closed would go into one big space of negative air. The culprit was the exhaust hoods and the make up air were way out of balance. Employees said scared the piss out of them when they saw the flame lurching out at the bottom then disappear back into the water heater.
So much good information! some of these guys are buried in their phones? Hopefully takin notes. Haha
Crap a little roll out. Damn I became part of the blue flame team. Complaint in crawl space they said would get booms. So I did visual did not see anything. To do this you climb down into the pit with the furnace. Now wired up long jumper wire to thermostat connection and climbed out of pit for safety and started heater over and over again. Did not have extension mirror with me. Just could not get it to make boom. So crawled over the concrete wall back down with the heater and first attempt to start it again. I remember seeing the blue flame cruising right along the dirt right to my face then remember the boom. There is no room to move or do anything. That was an emergency room call. now eyelashes, eyebrows burned off with slight no permanent damage to both eyeballs.couple of days running around with both eyes covered. I was wearing a blue jean vest with the fake lambswool and you could see where it burned some of the that up and around the collar. I promise you that was the last time I did it that way. Lmao
Wear safety glasses at all times. Been there unfortunately done that. No permanent issues, Luck was on your side.
@hvacr school reminder : put your thumb over the adjustment screw port when checking gas pressures because some furnaces will change once the adjustment screw cap is back on.
Don't jump safeties or leave them on either there for a reason
I have a 30 year old Bryant Furnace. This season found the humidifier cage motor not running. It's a Skuttle bypass humidifier. Furnace would run a while then shutdown with code 33. China supply for the motor is way out so I blocked the bypass bringing back hot air into the inlet side and no more code 33. Also installed a cheap filter for better air flow. I don't know which really fixed it. I know there's no flameout. I suppose it was the hot air loop back with no cooling in the humidifier.
Good instructions but I think you should mention that different counties and different states have different rules for PVC pipe for use in heating since NY state just changed the rules of use for that pipeline
Great overview of the Basics. You get an A-
"Control board goes through safety check" should be the next sequence after "Call for heat". Inducer will not come on if pressure switch is closed or if limit is open
Generally it will run with limit open to exhaust any potential flue gas/heat
There are SOME manufactures that have spdt pressure switches. The control board will want to see that the switch reversed position during shut down before the next cycle. Also, the pressure switch "helps" monitor the HX, if the HX cannot be put into a negative pressure, the switch may not close, requiring further inspection of the HX possibly.
👍
Its funny to see you Florida guys so mystified about gas furnaces as I work up here in NY. We probably feel the same about heat pumps. I hate heat pumps
Here in Maryland we have all of the above- from heat pumps to gas furnaces haha. Having 4 seasons is a blessing and a curse.
Busy all seasons here in VA.
I love heat pumps, what do you hate about them?
The guy who can't stop bouncing his leg violently is the one you never want to hire or be around.
Gas leak and Co testing should be done on all gas oil and ac units after work is carried out
No need for a furnace in Houston today Dec. 29th. It’s 81 degrees here.
Hi. from the snowbanks of ottawa canada
Start with order of operations of a gas furnace. Call for heat.Control board verfies pressure switch is open. Inducer gets 120v. Pressure switch closes. Hot surface ignitor gets 120v. Gas valve gets 24v. Flame sensor proves flame. Blower motor starts (after delay). Magic.
Even for all that to happen: you need 24v from xfrmr,, through 3 or 5v fuse, thought limits (rollout and high limit, to the control board terminal strip. To the thermostat and then call for heat at W or Hear pump...
It's nice working on simply systems like those. Up here in Canada where you cannot install old mid efficiency furnaces we have a more complicated sequence of operations. We have calibrations cycles for inducer motors. Communication verification on blowers. Feed back from discharge air sensors and return air sensors. So on and so on. However when I teach new guys I usually start with the same sequence as described but including the transformer, low voltage control terminals, and the rest of the safety string.
Control board verifies pressure switches are open and limits are closed
@@adamradley4407 Here in Chicagoland all the yuppies have those too. I'd say it's about 30% high efficiency. You're making it sound way more complicated than it is though.
@@JohnDoe-jt9oq I am not only referring to high efficiency though as those are the only "type" that can be installed. I am referring to modulating furnaces on communicating systems. With those you can't even take simple pressure switch readings as they are all referenced to either gas valves or transducers. To make matters worse if they are set up on zoning systems you end up with even more issues. Yes some are not complicated but more and more of them need technical data sheets to correctly diagnose the issues. Just think of the carrier, York, lennox type communicating systems. As long as they work it's fantastic. Show up to one of those with the Co p,ain't of an intermittent issue and you'll be there for a while
ive got one for ya how about 3 burners , 2 with flame one no flame the one with no flame has a flame sensor above it that shuts down the system because of no flame present on that tube, anyway any thoughts as to what is causing that tube to not light?
Probably low gas pressure. Could also be a blockage preventing gas from reaching that burner.or dirty burner
Blockage at the spud.
Blockage at the jets coming out of the fuel rail is a high likelihood. My next guess would be a weird amount of pressure coming from the valve.
I’ve never worked on a furnace before. Forgot everything about my class 😔
I can't watch anymore
you can teach the class
@@caru3257 I probably should
@@MiHeatingGuy Do us a favor.
I agree this is painful to watch being an OHIO HVAC/R contractor.
I was able to say thermocouple faster than your students. I just dated myself lol. 42 year cable TV veteran here.
I had a Coleman heater complaint something smelled like it was burning. Renters called fire department. "Fire department flagged heater" So I tested heater worked fine could not find anything wrong. At night time get call smell is back. What it ended up being the blower motor was going out when it started warming up the motor started slowing down getting everything very toasty and heating up the dust and motor getting really hot. No high limit trip. No error codes. changed blower motor and the unit has been flawless ever since.
Fascinating story maybe if you keep posting them someone will hire you.
@@waytospergtherebro I am self employed and get hired daily. Thank you.
lol dude in front row is dying, he cant stand sitting there even though the info is good stuff. reminds me of me :)
No wonder we cant get recovery tanks in Canada.. They are all in Florida
Hahahaha. Thats like an air to air heat pump here in the NE ( residential ). While you do see them.....its not all that common
Can you test from me?
Nitrogen isn't explosive. But the breaking of nitrogen bonds is a fundamental part of most explosives.
I'm assuming that's what he meant by "nitrogen is explosive"
You can get one flue gas tester to do all these tasks
Yoooooo
I think gas furnaces are safer than you give em credit for, at least untill some dumbass starts bypassing limit switches instead of finding the reason for the limits to be tripping. 👍
Now I know why it took 7 years for my furnace to be installed correctly. Sad I have to train myself to ensure everything is working correctly. Seems like none of the students there care are all.
Gas leak Bubble test
1:10:47 😂
I w be shy to be in the class with that pretty blodie girl there
Where you learned from “nitrogen is explosive “ really. That is How you cheat on your crews.
I’ll be pissed if I was the owner of tan company , Pay for this good class , and some of those bozos not even paying attention…. Drain cleaners for life I guess
Nitrogen is explosive? WTF?
It would become under high pressure if it was left in the evap a-frame and was heated by the flame below. It wouldn't burn but it would damage the evap coils.
Combustion analyzer...everytime.
Off the top nitrogen is not combustible hahaha
Dude in front row...stop moving your dam leg please...Im trying to conduct a class here.
No wonder all hvac guys these days are fake they all bought there careers🤣🤣🤣
What are you talking about?
Also *their
God these type of instructors talk so much unnecessary crap, repeating and repeating and telling what he gonna say instead of just saying it.