HEAT SEQUENCER Operation, Timing, & Testing

great explanation!

where does the motor fan wire go on which contact

hi when these sequencers are failing, do you get chatter/machine gun sound? i'm up north, first freezing cold day today since the winter, -13c. heat pump is off as too cold, aux heat strips took over in the air handler. It is a Trane 4tee3f37b1000aa, system about 12 years old. Noticed when the aux heat starts, there's a machine gun rapid fire/chatter sound at the air handler, right about where the red 20KW line comes in. i'm not really familiar with relays but could it be relays that turn the strips on and off?? (sounds like a machine gun, fairly loud if i put my ear on the panel). Once the heat gets going and the fan is up to speed, it seems to stop, and then starts again a bit when the heat cycle shuts off. I'm still getting aux heat but not sure if the 4 strips are all working 100%. if i lost a strip or 2 out of 4 would the others continue to work or would they all stop?, Is there a fire hazard if either a strip is burnt or relay coils chattering furiously. Or could this noise be something else like arcing at the strips? the system cycles on and off a lot when it's too cold for the heat pump, nothing new but i guess that's normal, since the air is hotter, it gets back to temp fast compared to heat pump. If its a relay, how long can it function like this? is failure imminent? i am diy, have diagnosed and fixed blower motor, module before and other things like outdoor cap.

Does this sound like a relay problem? thx I can easily open the from panel, just not sure what to look for.

So. Cal. Gas calls it a clicks on disc.

So I was practicing with my multimeter on a working electric furnace that has no problem works normally. I shut the breakers off, thermostat is off. I tested the sequencer for continuity across the top prongs which I thought should be open, yet I got a continuity beep. I did not take any wires off the sequencer. Should I take the wires off to test? Do I have to take all the wires off? Thanks for video

Great demonstration! Very didactic 👍

Great explanation of a sequencer. Thanks for posting this quality video! I have had problems with furnace in the past and wish I would have seen this simple explanation at that time.

Excellent video.

Excellent demo. Thanks

GREAT INFO! TY!

Awesome video 📹 👏 👌 👍 🙌 😀

So great thanks

so if im getting 21 volts at the wires going to the intermittent pilot module that are supposed to send power to the gas valve... that sequencer is the culprit ??!! I am getting correct voltage every where but at that point.... so the sequencer or the wires leaving the sequencer to the intermittent pilot are the culprits

Excellent tutorial. Thank you

Best explanation so far thank you

Good information thanks

good stuff. Thank you sir.

Amazing…thanks.

Got a furnace with no control/circuit board that blew a transformer (no fuse) replaced transformer and added fuse and blows the fuse instantly when i turn the power on! Any thoughts?

I'm a tech. Great job!

As the sequencer is heated is it dropping the rod or pushing the rod?

I apprecite this. Thanks.
So what is the sequencers job function?

Thank you for your video. I have very hard time to find a "new part" for my Sequencer: PN# 14SH22 H24V 305886 4/5 H1-15 C45-110, 1/3 H20-45 C1-30.

great explanation of how the sequencer works. Your explanations are excellent and easy to understand!!!

This man is the best at explaining things..

👍👍👍

Outstanding training vid. Doing a surgical autopsy on the components to see their innards is most enlightening.

Such an excellent video among other extremely useful videos, AC Service Tech 👍

Awesome video! Always wondered how these worked!

hi im a business owner and most heaters are gass around here and ao electric heat is kind of my weakness but i fill so condident after watching this video and the electric heat video that you did thank you so much

I guess it saves wire. But after a good night sleep and reading the wiring diagram my head scratching is ended.
The upper coil is wired in series, and taps off to blower motor. Couldn't figure out why it isn't always on. The blower just makes a big loop back to L1, so the entire circuit is just a big bus bar looking for a way out that the contractor supplies to L2, and the blower gets power backwards if relay doesn't kick on. Since AC doesn't care which way it works, all good.

I found an interesting problem with digital thermostats I never ran across before.
When they house is 32 degrees, the "AAA" batteries shut down in about 12-15 minutes with a low battery display, and no more use out of thermostat signals. So you need to work REAL fast or lose the control signals.

Do 240v hvac transformers supply 24v dc or ac current?

your videos has helped me so much

As always I like your videos and watching over and over getting more good information every time

Can this cause an intermittent problem with the HVAC blower starting but sometimes not? I changed my motor capacitor, HVAC runs fine but sometime the fan blower does not start.

What a flimsy design!

Dumb question do you take heater wires off sequencer and turn breaker and thermostat on and then check continuity or can you leave breaker off and just turn on thermostat?

Thank you for all the help you’ve provided me along my way! Question though, isn’t it risky to test ohms like that on sequencers? Since you’re getting 240v after the bottom thermodisc?

Thanks for your teaching, patience and your knowlege!!!!!

Question, my heat is not cutting off all the time ( even turning it off at the themostat it stays on ) I have to cut the heat off at the breaker for it to completely shut off. This problem is intermittent but it’s becoming more common. Could the heat sequencer be going bad,getting stuck? I’ve already replaced the themostat and the wires to the themostat seems to look good ( and none are touching- so I don’t think I have a short )

Very helpfull. Thank you

Heat sequencers reading 118ohms on the coil would mean bad sequencer? i had a few new heat kits read high out of box.

Ok still little confused. If the heater snaps or moves just one time, how is there a difference in timing of the switches? Should both rods move at the same movement time as well?

What would be the voltage between 4 and 5?

Excellent!

Should we be reading resistance to powered circuits? Safe because it's only 24v?