How Defrost Works on a Heat Pump! Explained Step by Step!

How does a dual fuel (Propane) defrost work (Trane 18xi) if cutout/balance temp is set to 26 degrees? And temp never gets above 26 for a few days?

Its amazing how refined the operation of these machines is, while at the same time its comical how archaic and sloppy the controls are.

Very nice video. Thank you very much.

Really good video!

Is there a timer on how long the heat pump will run in heat mode before the elements will turn on? My hp will run to about 88 deg, then temp will start to drop (about 5 min), and the elements will turn on until the set temp is reached. this happens every time I start the hp in heating, even if I continually, adjust the set temp to turn off the hp and them turn it right back on. Service tech told me it is running fine, but could not explain why the elements keep turning on every time. Thanks for any help.

I would think that a hot gas bypass is more efficient for defrosting and consumes less power than turning on a resistance coil.

what happens to the inside coil during defrost ? system basically runny on ac mode wouldn’t the inside could be cold and counter act the electric heat?

Can the heat pump only go into defrost on a heat call or does the DTS put it into defrost automatically no matter what if heat pump is running of not Great Video Thanks

My AC contensate pump do not start automatic when the reservoir tank is full but the contender outside get shut off and air handler keep running

Excellent explanation of what happens in heat pump mode.

Great explanation Craig 👍

You also seem like a very positive and great person, thankyou Craig!

You make everything so simple man THANKYOU!

Your series of videos helped me locate and fix a high voltage short in the condenser and a low voltage short in the thermostat wire. This was after the professional hvac techs gave up. Thank you for creating the excellent heat pump videos and for your excellent explanations in each and every one of them!

You’re a wonderful teacher, so eloquent with your words. Very intelligent friend, thank you for your efforts and knowledge!

I don’t understand. So the 60 minute timer is just to have the board check one switch every 60 minutes? If it is why not keep it at 30 minutes instead so it check as often as possible since the temperature switch is the one actually making the decision to turn on defrost?

Good job on explaining easy to understand you!

During defrost mode is the evaporator getting cold or does refrigerant not reach indoor coil?

Does a heat pump make a loud woosh sound during this process? I’m concerned something is wrong with my girlfriends condenser.

When in air conditioning mode, is there a similar defrost cycle to prevent freezing of the indoor coil? Why not? Is it because ambient temp in the home rarely gets so close to the freezing point? If you do see freezing of the indoor coil while in AC mode, do you think of other causes like a dirty filter, low freon charge, or other causes of poor air flow?

Any clearer and I’ll see my reflection 😂all jokes aside awesome video and very informative.

Great detail in your teaching, keep it up.
Perhaps you could help, I need a parts catalog for an old Goodman model CPK224-1B heat pump.
I'm having trouble finding the right reversing valve coil.

Master class teacher - really clarifies the defrost

You are the best!

Can I ask a question about a 4 zone mini split heat hump?
I have oddities in my defrost cycle. I have a 4 zone C&H Sophia with ceiling cassettes. Usually all cassettes will defrost together but I have one cassette that will go into a defrost cycle when the other cassettes are still heating. Occasionally that cassette will stay in defrost and not complete the cycle. I have also had two cassettes (only two running at the time) that did not complete the defrost cycle and just didn't start up again. Power cycling returns proper function. This is a new system and my first mini split so I am still learning but this seems like odd behavior. Any thoughts would be appreciated.
Thank you

Subscribed! Thanks for the video, very informative! Quick question: While the system is in defrost mode, does the fan inside the house runs simultaneously? If so, why?

Awesome Vid, I needed this refresher!

My defrost is set to 30 minutes will this be ok

Awesome video

Why don't they build heating elements into the coils to prevent this? It would potentially use less electricity than the coils in the handler IMO. It would also prevent the excessive reversing valve use.

Hi. I’m a very tech savvy homeowner. My heat pump was diagnosed with a bad defrost board. I would like to do a self install. Other than swapping out the board, does it require any kind of recalibration or anything?

DIYer here, .... wow mind bending. big respect to you pros!

mine pumps cold air when in defrost mode

Hi, thanks for a very helpful video that you've shared with us. My question is that when it is difrosting and the gun of thr heat pump stoped working, is it normal that the compressor making a huming noise. should i let it run?; if so for how long it must run to defrost the heat pump. thank you.

Found my defrost sensor dangling, disconnected from the coil tubing, where should it be mounted, before/after the "evaporator"?

Thank you very much for your videos. They always help me to understand HVAC and to improve my skills every time.

This nigga can teach

I have been an instructor and in the field for 30yrs. This is an EXCELLENT presentation on time/temp defrost system! GOOD JOB!!

Off the subject what is a reset relay?? And how is it drawn? Thank u

Awesome job. If you could do a video on furnace and the components and maybe show the wiring that would be awesome

heat pumps work great, without power, just ask Texas! (ok that was an uncalled for low blow lol) I almost feel bad about their overall not expecting the worst and having some form of backup plans in place or at minimum some work-around means. :| sad place of life survival skills and surroundings means to accomplish such the USA has become

Really good explanation very clear am glad that your share all your knowledge of hvac thanks. :)

I currently have a heat pump at my residence. I'll never own another one again. Piece of shit. Not very warm in the winter and not very cold in the summer.

Buy his book! Great investment

I've asked this question several times online and nobody ever seems to know the answer. You are amazing!

Question what is the lowest outdoor temps that these things run in? I have had the things running in temps to mid teens. Ohio.. Also in a pinch I have had the dfs go bad and jumped it out till new one arrived. It would be in defrost for 10 min and go back into hp operation. Carrier did not know if it would work but it does because of the timer. Great video.. subscribed.

Sir there is a Hitachi inverter AC. R-410a has gas. Ampere 4.1. But sir cooling is not happening. What's the problem with that, sir?