This guy helps out so much and he teaches more than I’ve learned from guys on the job sites in four years of doing this. These videos could really help you become a better tech and get proficient with your job. Thank you.
Subscribed because of this perfect explanation…in a loop. I have adhd, it’s hard taking in new information with all of the current info bouncing around in my head but this makes it easier to comprehend.
Immediately after the thermostat calls for heat a quick self check of the pressure switch circuit happens. This ensures the pressure switch contacts are open prior to the vent motor turning on. This is in addition to the constantly supervised heat switches safety circuit check which ensures they are all in the contacts closed position.
There is also a quick check that the flame prover isn't already closed prior to the ignitor heating up. I believe all of these checks happen in the same check process where the system checks that the pressure switch is open before the inducer motor starts up. If an error occurs in this phase and the inducer never powers up, before throwing a new inducer motor in it is important to verify all of the switches and sensors are in there proper states, which can be verified with a multimeter on continuity test. I know you probably know this already, it's for the people watching and trying to learn how to diag a gas furnace.
@dembones2560 more to the point so that a wayward gas technician doesn't attempt to bypass the pressure switch in an effort to give his customers temporary heat until he can source a new pressure switch. Providing you bypass the pressure switch correctly you still only get one cycle then the board looks for the pressure switch contact to be open before the next cycle can begin.
Great info! I recently took a class on hvac troubleshooting. The instructor was never this clear on the sequence. To be honest, he taught the class like he really didnt want to be there.
Mr. Craig thank you, before the inducer motor even starts, in most ignition sequences, not all, power from the boards' 24V, 120V back and forth signal proves the limit switches, proof of the safety circuitry first before any ignition process that is TFI trial for ignition. Thank you.
Wow wow hot stuff I have hard time understanding this thx for vid bro u make America great again I can be a better tech also thx to comments u guys help me understand HVAC better so I can help people help myself to be a better tech
@@John_Lee_not true, I had a service call on a recently installed gas furnace. House was completed mid summer, people moved in. Winter rolls around and they have no heat, guess what the issue was? Gas valve control switch was still turned off. It happens.
The most common one i've seen Is a pressure switch stuck Open And the furnace kicks on the burners 5 seconds at a time before shutting off and restarting the system until the third attempt. Then typically locks out the board. I've seen this under heavy rains or a froze up condensation tube on a 90% efficiency or better. Dirty in shot burners cause flame roll out and shut down burners and kick on fan full speed to cool down. From lack of maintaining or improperly install on LP conversion or wrong manifold pressure. I diagnose by symptoms. Sequence is pretty much consistent on most Residential gas and LP furnaces
I love your channel in the simple things but you forget to mention that the power has to go through the safeties before the light to make sure it's safe
Thank you, clear and precise. Have you ever encountered a controller board with a defective relay prohibiting the blower motor from turning on? However, the blower motor words for AC and Fan on modes?
Hey is there anyway you could do a video where you breakdown the wiring of the IFC board. I got it but it would be nice to have a video to explain it as well. Just for example that sec1 and sec 2 is receiving power from the step-down Transformer on the 24v side, etc. I'm just recently getting in the field and I need all the help I can get, especially with heating. Worked on a split system with and forced air gas furnace just like this but your videos are great. 👍
Also, if you run into one of those Carrier/Bryant/Heil furnaces: that is the worst inducer motor design ever made. If your furnace isn't working and nothing is happening, twist the inducer motor. They seize up over the summer and won't turn back on without some help for the first light of the year. Also, a TSB was issued for the pressure switch going into the Inducer motor. The inducer is so bad at removing water that it is constantly sloshing around in the inducer motor. The engineers knew this, that's why the pressure switch tubing has a loop going up. This is in an attempt to prevent water from going into the pressure switch. It's not enough, and they still have problems. There is a repair where you drill the hole out bigger, and add a new piece of pressure switch tubing that loops even higher. Pressure switch errors are some of the hardest and trickiest issues to diagnose. This most recent inducer motor and p-trap design is even worse than the old carrier 90% inducer design, which has its own list of inducer/p-trap/pressure switch issues. I regard this line of Carrier furnaces as the worst furnaces ever made.
@@JacobWar If the flames are lit, and stay on for more than a few seconds, you either have a bad blower motor, or a bad control board. If you have a volt meter, you can test to see if the blower motor is getting voltage. If it is, a bad blower is the most likely option. Normally when I blower motor goes bad it will make lots of loud noises when it tries to start. Unless it is a very variable speed blower than it won't make any noise.
@@David_Poole Thanks for all your information I learned more from your comments than the video. I knew the sequence already but there is more than he says and some are different the gas will flow even if there is not a ignitor you can use a long match. Anyhow maybe you can help with my problem. Lennox G60 don't know if it is the switch or ignitor. Inducer turns on and it shuts down in 20 seconds I do not hear a click from the pressure switch but the code is 3 alternating fast green flashes. And boy is it a bugger trying to get that ignitor off too tight a place to even move it ( brakcet) around to get the back hex screw off and no room to drop it below. Thanks just thinking it could be the pressure switch and wrong code or something if I do not hear a click
On some systems I believe the blower motor turns on first to blow out the cold air then the inducer motor and on ward, I could be wrong but I’m pretty sure York carrier Bryant and trane do that. May depend on the models tho
Normally open dampers should have 24v when the thermostat is satisfied or off and another zone is calling and if thermostat is calling damper will have 0 volts to it .
While visiting my family I tried to get some sleep with this exact same furnace and ignition sequence. Impossible to get six or seven hours of rest with this engine cycling.
The flame rod always has power so the board always senses for a flame. Pressure switches have to be open before the inducer motor is powered and thermal limits and flame rollout switches must be open. If all that is ok, the sequence of operation starts, thanks!
If you guys work on this for a living and you're proficient, The guys who work on commercial cooking equipment like ovens and fryers have basically the same job but with greater lunch options.
So I have a thermo pride furnace that runs as should as long as I turn the FAN or BLOWER on. Like I’ll hear the condensor kick on, see the condensation, and if I flick the fan ON switch I get cool air. Same with the heat. When I check voltage at the blower motor, I have 120 on the black wire and 86 on the red wire. Any tips?
My furnace wasn't heating; thought it was the ignitor (didn't glow) at fault, but then I noticed flame sensor was DIRTY. When I fixed flame sensor, it came back and heat. Is that the sequence for all furnaces?
So if my heater has steps 1-4 and somewhere between 4 and 6 the fire shuts off, but not always, it'll run for 5 minutes then turn off, is my flame sensor bad?
Yo I’m not getting 24v and it’s doing everything up until it’s supposed to release gas to kick on the furnace which it doesn’t. Would that mean it’s more then likely the circuit board
The flame rod always has power so the board always senses for a flame. Pressure switches have to be open before the inducer motor is powered and thermal limits and flame rollout switches must be open. If all that is ok, the sequence of operation starts, thanks!
The perfect HVAC loop doesn't exi-
Agreed, we only say that we are trying to help, thats it!
It’s brilliant
@@acservicetechchannel you can stop trying, you nailed it! Perfect, thank you.
Being in heating systems 1 class in college I’m going to watch this for the next 8 hours straight until it’s ingrained in my brain
Great stuff.
This guy helps out so much and he teaches more than I’ve learned from guys on the job sites in four years of doing this. These videos could really help you become a better tech and get proficient with your job. Thank you.
Thank you for watching!! I make these videos to help techs get ahead in their company and in the HVAC industry!
Clear and Concise, GREAT JOB as always 🥇
Glad you liked it!
Finally, somebody explained proper operation sequence. It's a base to troubleshoot any equipment. Good job.
Sequence of operations of a gas furnace-I used this twice in the last 2 days. Thanks for spelling it out so clearly!!
These are great videos for anyone wanting to learn more about HVAC
Subscribed because of this perfect explanation…in a loop. I have adhd, it’s hard taking in new information with all of the current info bouncing around in my head but this makes it easier to comprehend.
Immediately after the thermostat calls for heat a quick self check of the pressure switch circuit happens. This ensures the pressure switch contacts are open prior to the vent motor turning on. This is in addition to the constantly supervised heat switches safety circuit check which ensures they are all in the contacts closed position.
There is also a quick check that the flame prover isn't already closed prior to the ignitor heating up. I believe all of these checks happen in the same check process where the system checks that the pressure switch is open before the inducer motor starts up. If an error occurs in this phase and the inducer never powers up, before throwing a new inducer motor in it is important to verify all of the switches and sensors are in there proper states, which can be verified with a multimeter on continuity test. I know you probably know this already, it's for the people watching and trying to learn how to diag a gas furnace.
@dembones2560 more to the point so that a wayward gas technician doesn't attempt to bypass the pressure switch in an effort to give his customers temporary heat until he can source a new pressure switch. Providing you bypass the pressure switch correctly you still only get one cycle then the board looks for the pressure switch contact to be open before the next cycle can begin.
Great info! I recently took a class on hvac troubleshooting. The instructor was never this clear on the sequence. To be honest, he taught the class like he really didnt want to be there.
Good stuff, great illustration. Couldn’t be more simpler
Sequence of operation is key for troubleshooting anything great information
I appreciate the videos. Keep up the awesome work.
Thank you, sir!
Appreciate you watching!
I really like his teaching I bought his hundred-dollar book and consider it a good investment!
I'm not an HVAC tech but these are phenomenal videos. Great, great job.
Wow I'm so surprised someone on RUclips actually got everything 100% correct
Check out our website too! Weve got articles and books at acservicetech.com
Mr. Craig thank you, before the inducer motor even starts, in most ignition sequences, not all, power from the boards' 24V, 120V back and forth signal proves the limit switches, proof of the safety circuitry first before any ignition process that is TFI trial for ignition. Thank you.
Perfect sequence of operation explanation.
Awesome video I'm going to save this to send to customers if they want to know how their furnace works.
Absolutely love seeing how things work. HVAC tech or not.
I like my 1970s fedders furnace no circuit board is a beast. Never will die. Has fan motor, capacitor and glass fuse 😂
Great to have an audio checklist for us completely fresh fish
Wow wow hot stuff I have hard time understanding this thx for vid bro u make America great again I can be a better tech also thx to comments u guys help me understand HVAC better so I can help people help myself to be a better tech
Number one is all safeties are met rollouts high limits and so on, then your list
I bought his book years ago…great job!
Very well information, Great valuable knowledge by this guy . Thanks for the great video 👌
Glad you enjoyed it!
Number 8 is when you figure out theres an on and off switch on the gas valve and its turned off from the factory
Doesn't happen on a service call
@@John_Lee_not true, I had a service call on a recently installed gas furnace. House was completed mid summer, people moved in. Winter rolls around and they have no heat, guess what the issue was? Gas valve control switch was still turned off. It happens.
@@stephentorrey8727 ok bro that was an incomplete installation. Does it happen by itself though is what I was saying.....
This is great for DIY'ers
The most common one i've seen Is a pressure switch stuck Open And the furnace kicks on the burners 5 seconds at a time before shutting off and restarting the system until the third attempt. Then typically locks out the board. I've seen this under heavy rains or a froze up condensation tube on a 90% efficiency or better. Dirty in shot burners cause flame roll out and shut down burners and kick on fan full speed to cool down. From lack of maintaining or improperly install on LP conversion or wrong manifold pressure. I diagnose by symptoms. Sequence is pretty much consistent on most Residential gas and LP furnaces
I've been looking for this video for years....
Amazing 💯 craftsmanship 👏
This was done really nice. 😎✌️
Great short video these are awesome! ❄️
Drop them gems straight forward
Thank you
Well done
I love your channel in the simple things but you forget to mention that the power has to go through the safeties before the light to make sure it's safe
More of this please
Thanks for the information
This is perfect the sequence of events.
No it’s not
that is a beautiful set up
Great video 👍
#0 -board checks to see if pressure switch is not closed/stuck
Yup
#0b- confirms all limits closed
Excellent video.
Very concisely explained.
Great stuff!
Well said, well explained, keep up the great work, u are my number 1 professor.
Between the call for heat and the signal to the inducer, the system “checks” all limits
Thank you, clear and precise. Have you ever encountered a controller board with a defective relay prohibiting the blower motor from turning on? However, the blower motor words for AC and Fan on modes?
Awesome video
Nice thanks you
Nice. Great explanation 👍👍👍
Hey is there anyway you could do a video where you breakdown the wiring of the IFC board. I got it but it would be nice to have a video to explain it as well. Just for example that sec1 and sec 2 is receiving power from the step-down Transformer on the 24v side, etc. I'm just recently getting in the field and I need all the help I can get, especially with heating. Worked on a split system with and forced air gas furnace just like this but your videos are great. 👍
#1 should be making sure that there's power to the furnace. 🤗
Great video
I spent thousands on HVAC courses for 15 months and didn't learn anything. What a waste of money! It only took me a minute to learn that. Great video
Also, if you run into one of those Carrier/Bryant/Heil furnaces: that is the worst inducer motor design ever made. If your furnace isn't working and nothing is happening, twist the inducer motor. They seize up over the summer and won't turn back on without some help for the first light of the year.
Also, a TSB was issued for the pressure switch going into the Inducer motor. The inducer is so bad at removing water that it is constantly sloshing around in the inducer motor. The engineers knew this, that's why the pressure switch tubing has a loop going up. This is in an attempt to prevent water from going into the pressure switch. It's not enough, and they still have problems. There is a repair where you drill the hole out bigger, and add a new piece of pressure switch tubing that loops even higher.
Pressure switch errors are some of the hardest and trickiest issues to diagnose. This most recent inducer motor and p-trap design is even worse than the old carrier 90% inducer design, which has its own list of inducer/p-trap/pressure switch issues.
I regard this line of Carrier furnaces as the worst furnaces ever made.
The fire comes on my furnace but the fan is not coming on the blow the heat. Through the house
@@JacobWar If the flames are lit, and stay on for more than a few seconds, you either have a bad blower motor, or a bad control board. If you have a volt meter, you can test to see if the blower motor is getting voltage. If it is, a bad blower is the most likely option. Normally when I blower motor goes bad it will make lots of loud noises when it tries to start. Unless it is a very variable speed blower than it won't make any noise.
@@David_Poole Thanks for all your information I learned more from your comments than the video. I knew the sequence already but there is more than he says and some are different the gas will flow even if there is not a ignitor you can use a long match. Anyhow maybe you can help with my problem. Lennox G60 don't know if it is the switch or ignitor. Inducer turns on and it shuts down in 20 seconds I do not hear a click from the pressure switch but the code is 3 alternating fast green flashes. And boy is it a bugger trying to get that ignitor off too tight a place to even move it ( brakcet) around to get the back hex screw off and no room to drop it below. Thanks just thinking it could be the pressure switch and wrong code or something if I do not hear a click
Me with a simple Coleman furnace from 50 years ago.
B4 inducer starts, low voltage safety switches confirm connectivity
On some systems I believe the blower motor turns on first to blow out the cold air then the inducer motor and on ward, I could be wrong but I’m pretty sure York carrier Bryant and trane do that. May depend on the models tho
Can you please do a troubleshooting video on zone dampers.....please
Normally open dampers should have 24v when the thermostat is satisfied or off and another zone is calling and if thermostat is calling damper will have 0 volts to it .
very useful information
Awesome , thanks for the info
You bet!
You explained it perfectly
Great explanation
Bad ass vid man
Thanks for the content.... Very informative. Can you please do a video on split aircon sequence of operation
Great explanation!
Thanks so much. Now please have that written somewhere so I can print it out.
you do not have a pen and paper? Good Lord you ask for too much no one is your slave and he helped you for free
Well done my friend
Bravo 👏 Much appreciated
While visiting my family I tried to get some sleep with this exact same furnace and ignition sequence. Impossible to get six or seven hours of rest with this engine cycling.
This is so cool
Don't forget all the other safety precautions before lighting a furnace inside your home. Call a HVAC company.
I have a 20 year old RUUD has a brand new board and flame sensor, burners kick on for 8 sec then kick off
Great job . Can you make one for A/C please
Thank you
Thanks!
Jimmy, thanks so much!!
Couple other safeties have to prove before the furnace can turn on ?
The flame rod always has power so the board always senses for a flame. Pressure switches have to be open before the inducer motor is powered and thermal limits and flame rollout switches must be open. If all that is ok, the sequence of operation starts, thanks!
@@acservicetechchannel okay yes i was thinking high limits and roll out switches thanks :)
>The heating process starts when you turn the heat on.
Thank you
Good stuff
If you guys work on this for a living and you're proficient, The guys who work on commercial cooking equipment like ovens and fryers have basically the same job but with greater lunch options.
So I have a thermo pride furnace that runs as should as long as I turn the FAN or BLOWER on.
Like I’ll hear the condensor kick on, see the condensation, and if I flick the fan ON switch I get cool air.
Same with the heat.
When I check voltage at the blower motor, I have 120 on the black wire and 86 on the red wire.
Any tips?
Don't forget the rollout and high limit safety circuit
I don’t understand why carrier has a clear p-trap except for the side facing outward. Sure would save some time looking
Can you do a video about sequence of power?
My furnace wasn't heating; thought it was the ignitor (didn't glow) at fault, but then I noticed flame sensor was DIRTY. When I fixed flame sensor, it came back and heat. Is that the sequence for all furnaces?
Omg r u serious???
So maybe my flame sensor is the problem! I replaced my igniter with a new one and it still won't glow
Only thing that I might have added the roll-off switch if that's been tripped and won't start that sequence
So what can cause my gas furnace flame to stop after about 5 minutes after it comes on? I need help diagnosing this. Please.
So if my heater has steps 1-4 and somewhere between 4 and 6 the fire shuts off, but not always, it'll run for 5 minutes then turn off, is my flame sensor bad?
You should do one for low nox unit.
Craig can you do a video on adjusting pressure on the gas valve for single and second stage also static pressure if you don’t mind😊
Look up "acservicetech gas valve" We have that on single stage, 2 stage and 3 stage, thanks!
Do you have this info in paper form. I’d like to have it for future reference. Thank you
Yo I’m not getting 24v and it’s doing everything up until it’s supposed to release gas to kick on the furnace which it doesn’t. Would that mean it’s more then likely the circuit board
Question
When in heating mode is it suppose run in hi speed or medium speed
How many micro amps are needed to keep the gas valve open in this particular system?
Is there a way to minimize the blower in delay?
Can the same sequence of operations be the same as the Hi Delta Raypak boilers?
Yep, diagnostics.
I think 💬 my system does not have pressure switch. Is this possible?
Carrier roof package 📦
What about the prestart safety check of the limits?
What about the flame rollout switch
You left out one step at the beginning. It first looks to see if pressure switches are closed before turning on inducer motor
The flame rod always has power so the board always senses for a flame. Pressure switches have to be open before the inducer motor is powered and thermal limits and flame rollout switches must be open. If all that is ok, the sequence of operation starts, thanks!
@@acservicetechchannelflame roll outs are closed not open