Gas Furnace Class w/ Bert
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- Опубліковано 5 жов 2024
- Bert teaches a gas furnace class. He covers components, the sequence of operations, diagnostics, and safety. Many of the concepts he covers can also apply to gas pool heaters, which we often come across in our Central Florida market.
Furnaces come in multiple types. One of the more rudimentary types is the natural draft furnace, which doesn’t have an exhaust blower and relies on the rising hot air to draw in more air for open combustion. Induced draft furnaces also draw in air somewhat similarly to natural draft furnaces, but they have an inducer fan motor that pulls air in. High-efficiency condensing furnaces create their own condensation and have closed combustion.
Unlike heat pumps, furnaces have fire. To create a fire, we need fuel (like natural gas or oil), oxygen, and heat. We get a flame when there is the rapid oxidation of fuel, resulting in the release of heat. Since furnaces bring fire into our customers’ homes, we need to keep safety in mind.
Furnaces have many parts that are integral to proper operation. One is the inducer fan blower, which is powered by 120v and pulls in air for combustion. It also allows negative pressure to “push” air out of the exhaust. The pressure or safety switch proves that there is adequate airflow by closing under a vacuum created by the inducer blower. Limit switches are normally closed and open under abnormally high heat; you may have to reset these manually, but bimetal limit switches reset automatically.
There are a few different ignition strategies, including hot-surface (HSI), intermittent-spark (ISI), and direct-spark (DS). HSI tends to be the most common, though some manufacturers still make systems with direct-spark igniters. In the Central Florida market, ISI is common on pool heaters.
Gas valves, which supply the gas, are normally closed and open when 24v power is applied to the coil. The gas valve also drops gas pressure to the manifold. Flame sensors detect if there is a flame; when a flame is present, a small DC current passes from the rod to ground via the flame, and that signal gets picked up by the board. Flame sensors need to stay clean to work properly, so we should avoid touching the metal.
Each part has a role in the sequence of operations. First, the furnace receives a W call on the control board from the thermostat. The control board then confirms that the pressure switch is open to ensure that the switch hasn’t failed. Then, the inducer fan starts, causing the pressure switch to close. All the while, the board checks to make sure the safety circuits are closed. Then, the ignition sequence begins; some ignition sequences have delays. Then, the gas valve opens, and the flame sensor proves the flame. Once the flame has been proven, the blower starts. Bert then demonstrates the sequence of operations on a training unit at the Kalos HQ.
When getting into diagnostics, a diagnostic chart will be your best friend. It will contain error codes and a list of possible causes, as well as things to look out for when solving the problem. Furnaces need an adequate combustion air supply, and we need to look at the infrastructure to make sure there aren’t any possible pressure or venting problems that could cause dangerous conditions like carbon monoxide production or flame rollout.
Some of the most common diagnostic issues include a blocked flue vent pipe, a jammed blower wheel, a damaged or loose hose, a failed inducer blower, a failed switch, loose wires, or a failed board. Limit lockout error codes are also common, and there are a number of things we should be checking, including flame rollout conditions, broken boards, loose wires, and partially blocked exhaust pipes. Failure to prove ignition is another common problem, and we have to look for issues with our gas valve, flame rod, damaged wires, and the igniter itself. Many of the same diagnostic concerns, especially regarding flame rollout and gas valve failures, are also applicable to gas pool heaters.
When working on gas appliances, some of the most common safety concerns include gas leaks, carbon monoxide, and flame rollout. When someone smells gas, you should take those concerns seriously. Carbon monoxide, on the other hand, is odorless and can be a silent killer; we can reduce CO in a house by advising customers to have a heat pump installed and use a CO detector. We can also make sure the heat exchangers are in good condition-not rusted out or cracked.
Read all the tech tips, take the quizzes, and find our handy calculators at www.hvacrschoo....
BERT
Excellent work. This video definitely allows one to "learn some things you've forgotten along the way, as well as remind you of some things you forgot to know in the first place."
Everyone LOVES Bert!!!!!!!!!!!!!!!!!!!!
I don’t recommend any installer to commission gas furnaces. They need to be set correctly the first time and combustion analysis. Our installers put them in and us service techs take care of the rest. Unless you have proper certifications or training. But great video. Deff one of the best
Excellent work Bart.
Thank you Bert and Team for this video. Awesome work.
Thank you Bert. Great job.
Definitely read code upon arrival! Been there with code not coming back... ugh.
Excellent videos! Keep up the great work you do! Thank you
Good class. Thank you Bret.
I also found Brent very helpful
its bert guys…bert
Brenton is ok, but Bert is the man.
I am an Instructor for the local Apprenticeship program. Natural gas is lighter than air not heavier. Propane is heavier than air. Also I wouldn't have rookies using an impact driver to tighten the flame sensor screw. If you strip out that screw hole you will have a bad day.
Thank you for this very informative video. I was hoping to find out how to get past a lock out.
Also, it is important to note that propane is heavier than air and it sinks and can suffocate. Entire herds of farm animals have died in lowlands.
Natural gas is lighter than air, and it rises. It's a terrible contributor to our Greenhouse Gasses. It's the one with the rotten egg smell from an additive.
(I graduated in Biochemistry.)
Like them alot.
Liked so much I purchased and installed this evening.
Goes great with the OEM LEDs.
Still unsure why my truck didn't come with LED fog lights to begin with.
Thanks
Great Vid Great Job Bert Keeping it Interesting and Fun / Funny I would Say You Pretty Much Nailed it Thanks for Sharing !!!
1:12:45 what are the push-on alligator clip leads that Bert puts on his multimeter?
Thankyou for this video.
I cant speak for all brands, but those carriers do have code retrieval to see what code was if power was reset. I think you have open the limit circuit and quickly close it again.
The instructor reminds me of the Jimmy helpert, form "the office " tv series
Bert 2024!
What's the difference between combustion air and makeup air??
when did Jamie kenedy start teaching HVAC
Bert reminds me of lucifer on supernatural lol, great video and class!
Up North he said. I am in Virginia, the capital of the South, and I see those furnaces all the time.
Bert...i enjoyed, and learned from this video. You should consider entertainment, maybe stand up comedy for HVAC.
Nice job but after your clear trap that vent needs to be higher than the water line of the drain pan or water will pour out of it if the line clogged up after it
8:59 - "Ask me anything you want. I can probably come up with an answer."
I feel like there’s a gap between 1990 and 2022 that we’ve missed.
55:16 - Another reason for flame rollout is a cracked heat exchanger. It’s time to crack out the combustion analyzer.
Touching the flame sensor my cause some oil from the skin to coat the sensor and this my pick up dust. I always use alcohol to clean the sensor if I touch it.
Non tech here. Thanks for all the fundamental knowledge in case my furnace doesnt work. I bought a flame sensor and limit switches to have on hand should I have an outage. Dont want to wait on a cold day. Gonna swap out my old furnace blower motor this summer as a prevention in anticipation of next winter.
HILARIOUS and informative 😂 🤓
Muchas Gracias
I gotta watch this like 10x ... 🤦
But I will learn 😤
I’m in northwest fl furnaces are somewhat common around here maybe 15 percent of units
Me in Colorado realizing people in other parts of the country don’t know anything about furnaces 😂
What gave it to you?... "White silicone with fusable link"
I'm from Phoenix and moved to Washington, I didn't know what a furnace looked like lol
Best frog speech ever
.02 draft or .20 draft when hot. Inches of water column. There are tools for this. What about the .10”we and the blower causes it to open. Basic or advanced we all need to use the tools needed for diagnosis.
Quality.
Had a bird stuck head first in the inducer blower wheel, his beak was clicking on the wheel sounded like a ticking lifter my jeep. Furnace would try to start .
.68kg /Sm3 natural gas versus Atmospheric (air) at
1.0kg/Sm3
On my furnace igniter stops working time by time, is it pressure sensor or control board issue?
Using what you learned about sequence of operation on this vid, check pressure switch with meter to be sure it does what it's supposed to.
@@Robnord1 Thank you Rob!
One more button. This isn't Saturday Night Fever
Very niece
This guy is freken hilarious lol hahaha. I like 19:44 min what he says
Florida guys talking about furnaces.
I didn’t know Bert was so funny
When is he not funny?😂😂
Don't forget, he used to work as a clown.
If you would like any tips feel free to ask I have brazed my body weight in silfos lol
Porcelain should not have oil either
typical CO sensors alarm at 70 ppm. this is too late and they shouldn't sell these as it gives folks a false sense of security
29:38😂
The Pizza man
lol. But good video 👍
Lol since no one else laughed
Bert is too distracting for this
It was a good video. But glad to see I wasn’t the only one lol
I don’t know what this means but I feel flattered 😊😂
A frog??? Wtfrog??