how does the heat pump reversing valve work

[@vernroach3413]

I tell everyone I know, if they want to know, what a reversing valve does, and/or how it works, watch this video...It's explained better on this video, by "The GrayFurnaceMan", than anywhere else, period....I often sit and watch with them and they too, understand afterward....What a great teaching tool...I know sir, you must get tired of me saying this, but thanks again.

[@grayfurnaceman]

Welcome GFM

[@mattagee8104]

Best video on reversing valves I have watched as of yet. Great job !

[@wildman411]

thanks i am not an ac man but i enjoy learning how things work. I VERY MUCH THANK YOU FOR YOUR VIDEO MAY GOD BLESS YOU AND YOUR WHOLE FAMILY

[@vernroach3413]

I watch many videos on HVAC, to learn more and to help me better instruct classes....I know watching this mans explanations, make me better understand....Then I can share what I have learned of what is exactly going on...I know, I'm a better instructor for doing so...After watching Grayfurnaceman, I am not only refreshing myself, I am learning, it feels good, and my students will learn from them too....Thank you sir, for what you do....Vernon.

[@mattnichols2]

Great Video! Thanks! I appreciate the layman's terms and clear direction. I have a Carrier heat pump that is doing just the same thing you're talking about, and I actually thought this last summer that the compressor was going because it was smoking hot after freezing up. I got it to last for the summer, but I just changed the thermostat for no heat issue and the coil actually frosted on heat mode! I believe this is the culprit right here! Thanks again from a newbie HVAC tech

[@grayfurnaceman]

+mattnichols2 Welcome GFM

[@victory21222]

Exellent. I have been an HVAC&R tech for 36 years and I give your video 6 stars out of 5!!

[@grayfurnaceman]

Thanks for the support. GFM

[@melvin292]

You absolutely have a superb talent for teaching. Seems your knowledge of this subject is endless. You are certainly appreciated.

[@grayfurnaceman]

Thanks for the support. GFM

[@PastorDaveTube]

I liked the explanation, the proper way to install, and of course how you cut it in half to see the inner guts. Good job and Great Video Thanks!

[@willwinston161]

Dave Reinhardt how do you check for a bad reversing valve

[@grayfurnaceman]

I have not done a video on replacement of the valve. One for the future. Testing the valve is somewhat complex. When you energize the solenoid, you have to listen to the movement of the valve. It should make a whoosh sound. No whoosh, bad valve or solenoid. I did a video on temp difference testing. Look for "testing the reversing valve" on my channel. GFM

[@minnesotasalamander5913]

Good cut- away view of the R.V. and good explanation. Thanks

[@joeoconnor2761]

Great training video! I will use it to help my guys understand reversing valves. The only way I have found to be 100% sure if the reversing valve is stuck in the middle or if the compressor is running and not pumping is to very slowly crimp off the hot gas discharge and monitor compressor amp draws. On some units like a Trane, you can look at the pressure if crimped slowly by the reversing valve. After misdiagnosing several compressors/reversing valves I made this test mandatory for my technicians. Fixing a line is much better than a misdiagnosis any day!

[@acoustic4037]

Why not look at the TD of the lines in and out of the valve? Why not look at them with a thermal cam? That should make quick, accurate diagnosis possible, no?

[@joeoconnor2761]

If the reversing valve is stuck in the middle there is no seperation between the low and high side of the system therefore the pressures in the hot gas discharge line and the suction line are very close to the exact same. In other words the suction line is sucking the same amount of refrigerant as the hot gas discharge is putting out. If there is no pressure difference how can there be a temperature difference? The lines will be warm either way because the compressor and lines will warm up from the heat of the compressor motor. Even if the compressor is pumping the refrigerant the refrigerant can't cool the compressor due to no change in state. You cant measure the heat of compression if there is no pressure being made. If the compressor is pumping there is good flow but no pressure is being made to measure the heat of compression. Nothing is being compressed except in a very small area inside the compressor. The compressor is very hot anyway due to no refrigerant cooling it. It is impossible to tell for sure. Looking at the temp difference in and out of the reversing valve works great if the valve is not fully seated in one mode or the other. In that case the pressures will not be the same in both the hot gas line and the suction line and you can make a good diagnosis. If the reversing valve is stuck very close to the center position you will need to crimp down on the hot gas line slowly and see what happens to be sure of your diagnosis. Good luck!

[@joeoconnor2761]

I understand what you mean and you are 100% correct if the RV is 80 or 90% seated in 1 position or the other. I was talking about how to figure out if you have a copmressor running and not pumping or a RV stuck very close to the middle position when there would be no pressure difference between the hot gas discharge and the suction line of the compressor. No pressure difference means no temperature difference that is measureably reliable enough to determine which major component has failed. Crimping down the hot gas discharge SLOWLY and watch the compressor amp draw, the sound of the compressor and possibly the hot gas pressure rise if you have a schrader there for full time high side pressure port. This way you will know for sure if the compressor is able to pump so you can be 100% sure of your diagnisis. Using a magnet can be helpful in some cases but if the RV is stuck a magnet will very likely not move it and if the compressor is running and not pumping even if you did move the RV how would you know it even moved? Nothing would change. Crimping the hot gas line is the only 100% sure way I know of to be sure of your diaognosis.

[@MrTechnicalsolution]

Good video we don't use reversing in Jamaica so I learned a lot.

[@adamrichardson6918]

You sir have a great video on this topic. I've learned over the years to troubleshoot my HVAC problems then call an HVAC company and tell them the repair I need.....otherwise some will just try and tell you everything needs replaced (compressor, whole unit, etc....)...not everyone in their field should be in their field.....there are great techs and there are horrible techs....just like lawyers and doctors.

[@evannovack7244]

This video is a great teaching tool. Will definitely share it with the techs.

[@grayfurnaceman]

Accumulators in HPs are used to prevent liquid floodback from lowering outdoor temps. Lower OD temps reduce the amount of refrigerant needed, so the liquid goes into the accumulator. If a rev valve sticks midway, hot discharge gas will pass from discharge to suction and overheat both valve and compressor. Hope this helps. GFM

[@hg2.]

Thanks for an another trade-mark "anatomy of AC" video!

[@grayfurnaceman]

Welcome GFM

[@paralegalty]

a fantastic explanation + visual, thank you.

[@eddieq1905]

Thank you. I'll have a go tonight at work. Many thanks.

[@richarddumas5457]

OMG What a great job. THANK YOU Just what I was looking for. How it works without all the fluf. Great JOB.

[@grayfurnaceman]

Thanks for the support. GFM

[@hg2.]

Right. There are lots of videos from "experts", but they aren't good teachers, like GFM.

[@michaelcostello6991]

Super video on very important component that causes problems. Thank you for sharing

[@grayfurnaceman]

Welcome GFM

[@PWiebe]

Excellent explanation. It's clear you have some real world experience with them. Thanks

[@johnnievizzle9051]

grayfurnaceman, ive been a fan for at least 3 yrs since i was in "refridgerater college"(did installs before that) now ive been troubleshooting for a couple yrs and i still come watch your vids sometimes cause you have such a thorough knowledge of hvac. i did just what you said thus summer.i changed rev valve and comp was bad. i took temp readings,warned the cust could be comp.still hurt when i was wrong.i just got a youtube so i could leave a comment, and i wanted to say how much i appreciated your vids over the yrs, and if your ever in nc ide love to buy you lunch. (have to be a sat, thats the only day i eat lunch)

[@grayfurnaceman]

I'd love to if I get there. It means a lot to hear I have made a difference. Hope you and yours are ok after the storm. GFM

[@pauleohl]

Excellent video. Good content and good demonstration hardware.

[@jewelwilliams777]

Thanks for the video ,it’s help me to understand reversing valve a lot on heat pump

[@grayfurnaceman]

Welcome GFM

[@MCGEE1115]

Always wanted to know how they worked! Thanks

[@grayfurnaceman]

Welcome GFM

[@AUTurfman]

Very helpful video! I'm just getting into the HVAC industry, but on the sales side of it. I'm one of those guys that likes to know how things work though so that I can be the best at what I do, so I'm trying to learn as much as I can. Thank you for this.

[@grayfurnaceman]

AUTurfman Glad I can help. GFM

[@justgivemethetruth]

So simple .... really great video ... thanks! I am looking to learn about geo-thermal technology ... anything you could point me to or other videos would be awesome. That is a really nice demonstration.

[@grayfurnaceman]

Usually if the reversing valve has failed the unit will either stick either in cool or heat, or will stick halfway and do nothing. Running but no cool could be many things. Low refrigerant charge, failed compressor, plugged filter or frozen coil are some of the most common. Hope this helps. GFM

[@alexj0101]

Great explanation and demonstration

[@grayfurnaceman]

A hacksaw was used. Use care and move slowly to keep from making a mess of the components. It helps that you know where the components will be. GFM

[@josephmanriquez5696]

I truly appreciate all the vids man!! Great teaching and Great learning!!!

[@hubercats]

Great video. Thanks so much for making and sharing it.

[@grayfurnaceman]

Welcome GFM

[@grayfurnaceman]

Thanks for the support GFM

[@grayfurnaceman]

Txvs should be ok. When you change from cool to heat, does the valve move? Is the head pressure higher than normal or lower than normal? Place the unit in cool and check suction pressure at the lineset suction tap, then the 3rd tap and see if there is a difference. Let me know. GFM

[@grayfurnaceman]

Yes, the geothermal system is simply a heat pump similar to an air source heat pump that picks up heat (or releases it) from the ground thru a ground loop filled with water or a well or a pond, lake.

[@douglasthompson2740]

Always very good stuff with a good presentation. Learn a lot from your videos. I would like to see some evaluations of the modern cold climate high efficiency mini splits from you. I have watched all your KZbin videos I believe and they are head and shoulders above the rest. Take care. Doug

[@saltrue1555]

Thank very instructive Reversing valves can be tricky. Thank you for explaining thank you

[@grayfurnaceman]

Welcome GFM

[@grayfurnaceman]

Actually, the valve has been quite good. They first came out in the late 50s and had a somewhat bad reputation for a while. Thanks for the comment. GFM

[@grayfurnaceman]

Certainly, the rev valve is the most sensitive to contaminates and brazing technique. Also low charge will increase operating temp. Once it has failed, its quite hard to tell what happened. I have never seen one with cast aluminum slide. Thanks for commenting. GFM

[@grayfurnaceman]

Thanks for the support. GFM

[@ToyotaGuy88]

Better than Carrier's video on reversing valves!

[@grayfurnaceman]

Thanks for the Kudos GFM

[@JamesSchenck]

This is an excellent video and an excellent channel. Thank you!

[@Rattletrap2]

Great explanation and demonstration! Thanks for taking the time to carefully dismantle the valve to show cut-away views. How much deviation in temperature do you recommend when troubleshooting the valve in operation. I always thought the two suction tubes should be the same, and the two discharge the same temperature. I have seen some books say up to 3 degrees is ok.

[@grayfurnaceman]

I have seen both 6 degrees and 3 degrees. Most failures are fairly obvious, no movement, loud hissing noise. Hope this helps. GFM

[@tstatech]

Your a life saver. I went out on a Goodman ssz14 today that was tripped out on thermal in heat mode. When it reset I checked all three ports. The common compressor suction port dropped to 0psig while the high and low ports equalized to @ 270psig. I then checked it cooling mode and it worked like a champ, 9'SH 14'SC in 45' OD temp with a field piece cold weather charging jacket on it. back in heat mode, same as before and wont run more than a minute. My 1st instinct was the OD TXV. but the reversing valve was nagging at me. The fact that it's been doing this non stop for more than a month really bothers me as the customer complaint was high electric bills. Knowing that the discharge will enter the common suction line is king. I thought that if it stopped halfway that it might block off the common suction line while opening the indoor and out door coils to each other. I sure don't want to change the TXV and still have the same problem. Then again I'd rather change the TXV than the reversing valve. Dreading changing the filter drier. It will have a new home, outside of the unit where it belongs not buried in the bottom of the unit, an inch away from the service valve. Best Reversing valve video I've seen yet.

[@grayfurnaceman]

If your unit works in cool, and the valve shifts, my guess is the TXV is not feeding. So you may get the easier TXV replacement! Glad I could help. GFM

[@grayfurnaceman]

+who ami I am not sure how you would do that. GFM

[@grayfurnaceman]

+who ami You can try it. No guarantees. GFM

[@grayfurnaceman]

+tstatech Thanks for the support. GFM

[@grayfurnaceman]

Yes, I do have one on a TXV. Put TXV in the uploads search engine. Drier, not yet, but soon. Hope this helps.

[@eddieq1905]

Great video thanks. I was curious what you used to open up the reversing valve. Only asking as I've just changed one in a Daikin VRV 2 R407C unit and was wanting to inspect the internals. Immediate thought was a hacksaw then I was concerned that the filings would go inside? Any advice would be welcomed. Thanks Eddie.

[@albmarku4379]

Best explanation ever! Thanks a lot! Long time to hear from you. I hope you are well. Best regards. Alb

[@grayfurnaceman]

Welcome GFM

[@carter102]

Are you finding many newer heat pump units use suction line accumulators to prevent the compressor from slugging-then-blowout of valves in the event the reversing valve is stuck mid way?

[@davida1hiwaaynet]

Thanks for making the cutaway and explaining how this works. I really appreciate it!

[@grayfurnaceman]

davida1hiwaaynet Welcome. GFM

[@grayfurnaceman]

I will put it on the list. Thanks GFM

[@FarmAlarm]

I have a few rooftop air conditioners/heat pumps. And one of them is backwards. The thermostat has to be on Heat for it to cool. And has to be on cool for it to pump heat out. I can tell you that the thermostat is Not hooked up backwards. Can the solenoid be wired backwards? Thanks

[@grayfurnaceman]

The solenoid cannot be hooked up backwards. One of the units may be of a different manufacturer that has the reversing valve plumbed differently. Other than that, the wiring or thermostat must be wired incorrectly. GFM

[@grayfurnaceman]

I would not think the rev valve would cause that. If they stick halfway, suction goes up and head goes down. I would be looking for a blockage. If you reverse the cycle does it still stay the same? Hope this helps. Let me know. GFM

[@efman2k3]

Awesome video. Thanks for posting!

[@grayfurnaceman]

efman2k3 Welcome GFM

[@TheKadoxman]

This is very clear great job

[@alonsomontes6579]

awesome video! thanks for taking the time to make this!

[@grayfurnaceman]

Welcome GFM

[@grayfurnaceman]

My thought on inductance of a coil without a core is that there is no concentration of the magnetic field so the back emf is smaller so higher amp draw. I have seen the same thing in contactors with stuck armatures. I suppose it is also a heat sink. Thanks for the response. GFM

[@FranciscoPerez-wl6iv]

great explanation for people like me (new student in this field )

[@grayfurnaceman]

Thanks for the support. GFM

[@robbeck67]

Thanks for the very informative video. I learned a lot!

[@rayregal6258]

great tutorial about it's I'll never forget this video's thanks.

[@anthonytika7409]

thanks very good tutorial very in-depth

[@grayfurnaceman]

+Anthony Tika Thanks for the support. GFM

[@sssttt6533]

Very great explaination. Big LIKE

[@grayfurnaceman]

Thanks for the support GFM

[@tserevenad]

excellent video, very helpful. thanks.

[@grayfurnaceman]

I would look to the liquid line service valve. Is it possible it is closed? Other possibilities are kinked line, etc. Let me know. GFM

[@rorlegger1]

Awesome video, I'm learning a lot from you, thanks for sharing your videos

[@grayfurnaceman]

+rorlegger1 Welcome GFM

[@tonym6920]

Great video and explanation, thanks!

[@grayfurnaceman]

Welcome GFM

[@waydav1s]

The reason the coil will burn up if left off is that the stem it mounts on changes the inductance AND is a heat-sink of sorts.

[@sean7193]

Excellent video Sir.

[@nickush7512]

Excellent, absolutely excellent, I learned a lot, so many thanks :)

[@fordracerguy]

This is a great video, thanks! I have an electric heat pump system (no aux heat). I just upgraded to a CT50 WiFi thermostat. When turning on cooling mode, the thermostat clicks, as well as the reversing valve. The problem is this click happens even when the A/C isn't actually blowing air. Is it normal for the reversing valve to be energized for hours or even days when the A/C isn't blowing air?

[@grayfurnaceman]

fordracerguy Some of them are energized until the heat/cool mode is changed. It does not hurt anything. GFM

[@oldtimedrumcorps]

We may have a sticking reversing valve. All signs point to it. Why would unit shift easily from heating mode to cooling at Tstat manually, but not when defrost board demands the shift? That 24 volts demand board should energize the coil as well ? Can there be a low pressure situation to the SOV at defrost board demand ? It should be there as well at SOV when T state is engaged manually from T stat. NO ??? Thanks

[@grayfurnaceman]

Right now I have not done any on geothermal. I will be doing some in the future. You might go to Water Furnace on the web. They make geothermal units and have some info. Thanks for the comment. GFM

[@ivanmikhaylov1103]

Thanks for the awesome presentation. At 5:25, you say: most of them are energized at cool. Do you know if it should be hot when it is energized? My reversing valve solenoid is hot, so one cannot hold fingers on it. It is energized when the system is switched to cool or even off. It is not energized only when it is on heat.

[@grayfurnaceman]

This sounds like the solenoid is not pulling in the armature completely. It will overdraw if it does not pull in completely or the solenoid is not fastened down tightly.. Normally, the solenoid will draw about 4 watts. GFM

[@ivanmikhaylov1103]

@@grayfurnaceman Thank you! I think you are right. And the reason might be that there is no enough freon pressure. I suspect that the reversing valve is leaking, because the whole issue has happened just after a few cold days, when the A/C was turned to heat. There is no visible trace of leakage, though. Can the reversing valve leak through its solenoid?

[@grayfurnaceman]

They can leak anywhere. There should be oil on any leak. GFM

[@IFIXCASTLES]

I've cut some open that failed due to the teflon diverter actually melting due to poor maintenance of the unit. I have open some that the diverter was probably cast aluminum.

[@daimlerblanco3493]

best video ever.

[@grayfurnaceman]

+Daimler Blanco Thanks for the support. GFM

[@Cbaxter5213]

Great video!! I'm a commercial tech, never see heat pumps. But as luck has it I get to help a family members unit. It's a r410a system, it runs for about 10 mins then the high side pressure starts slowly climbing. Is this a reversing valve issue? Of course i've cleaned the coils, done all the obvious checks.

[@grayfurnaceman]

I would be looking at superheat and subcool. Possible overcharge. GFM

[@VladVlad-pd4pi]

You are very good! Thx for videos!

[@GRIzZLY8902]

Good job!!!! Nice explanation.

[@grayfurnaceman]

Thanks GFM

[@darrylmonast3154]

Great video thanks a lot so helpful you should call garbage contaminates

[@9613metallica]

Thanks for this. Great explianation

[@grayfurnaceman]

+Jeremy Miller Welcome GFM

[@grayfurnaceman]

If I find one in the scrap yard, I will do one on it. GFM

[@menitojr6066]

Thanks for the info very good video! I just yesterday had to replace one of these on a water source hp and the thing was very awkward to get to i wrapped it in wet rags and put some thermotrap on it as well cus i was afraid of overheating the sucker but when i went to fire it off the valve was stuck in heating mode I must’ve melted the teflon or something or it may have been bad out of the box not to sure. But do you recommend any certain way of keeping the heat off of them as much as possible? Ill be going back there soon to replace it for a 2nd time and i dont want there to be a 3rd lol thanks again

[@grayfurnaceman]

There is nothing harder than brazing a reversing valve. The trick I found is to use a large tip on an oxyacetylene torch. You need to heat it fast. The easiest way to overheat the part is to use too low of heat because it takes too long. GFM

[@Mr05Tundra]

Great Video, Thanks for taking the time to fully explain the operation of a reversing valve, much appreciated. So, really there isn't any way to test the operation of the valve without the unit running right? The reason I ask is because I have 3 Heat pump circuits that have been serviced by another company, when I arrived on site, no refrigerant in the systems, pressure tested and no leaks. Compressor windings are good so I guess I'll have to charge it up and see what's wrong with it!

[@grayfurnaceman]

You usually do not need a full charge to test. I would charge only enough to get a pressure difference and it should shift. Hope this helps. GFM

[@deere3321]

Great explanation. The valve on mine was diagnosed as being stuck so it only works in cooling mode. With low LP prices, I don't use it as a heat source anymore. Is it necessary to replace it under these circumstances?

[@grayfurnaceman]

+deere3321 No. Just continue using it as an A/C. GFM

[@deere3321]

+grayfurnaceman. Thank you

[@ivanmelendez4239]

grayfurnaceman i can operate my equipment without not energice the reversing valve because i in puerto rico and we dont need heat pump mode true or false iam ac technician too thank you

[@Ojgville4l]

Great vid, all your vids are great, thanks. If you are replacing a compressor on a HP does it make sense to replace the reversing valve also? I know it's easier said then done.

[@gfriedman99]

GFM, I was wondering if you do a pump down with the reversing valve in heat mode would that allow you store the refrigerant in the indoor coil and linesets so you could work on the outdoor condensing unit? In my case I want to replace the accumulator. Thank you.

[@grayfurnaceman]

+Gene Friedman You can. Sometimes there will not be enough space in the coil and lineset. GFM

[@gfriedman99]

+grayfurnaceman That is interesting.... now what about on an AC condenser without reversing valve..... instead of closing the liquid line first as usual and pulling refrigerant into the suction port - could you close the suction port and force the refrigerant out the liquid line into the evap and lineset - or would that kill the compressor?

[@grayfurnaceman]

+Gene Friedman Nope. All it will do is pump into both the evap and the condenser. It won't kill the compressor unless you leave it on for a week. No such luck. GFM

[@gfriedman99]

+grayfurnaceman Ahhh, yes I see - the discharge from the compressor has to make its way out through the condenser coil first. Blast.... oh well it was worth a shot. Appreciate all you do.... thanks!

[@RODJUVENAL3]

YES IT DOES THE SAME ON COOL OR HEAT, SO ITS NOT THE TXVS RIGHT? I REPLACE THE FILTER DRIER, BLOW THE INSIDE COIL IS CLEAN, OPEN BOTH TXVS CHECK THE PISTON OR WHAT EVER YOU CALL THAT IS CLEAR. SO I DON'T KNOW ANY THING ALSO. THANKS

[@TheDangeFam]

greatest video of all time

[@grayfurnaceman]

Thanks for the support. GFM

[@patton6971]

Gray , if I have to replace a compressor in a heat pump will be smart to do valve at the same time because we don't know what causes the problem in the old compressor and please explain how the solenoid work in detail, I'm in Miami we don't have heat pumps here but I'm interested thanks

[@grayfurnaceman]

The choice to replace the reversing valve is somewhat tough because you cannot check operation because the compressor has failed. The rule I use is, if it is a locked rotor, no phosgene (R-22), no short to ground and less than 15 years old, do not replace the rev valve. Any of the above positive, replace the valve or replace the unit. GFM

[@RODJUVENAL3]

if the reversing valve sticks halfway , will this afect presures? i got a block in my heat pump some where, the compressor goes in to vacum and my head presure stays the same, even if i disconect the outside fan motor, any idea whats going on. thanks

[@justgivemethetruth]

Wouldn't this heat puimp reversing valve be used or useful in a geothermal system for changing from heating to air-conditioning in a building?

[@CoolasIce2]

Great video, but we didn't get to see the other side of the slide and what the seals look like. If you have that valve laying around and would like to update the vid, I'd appreciate it. Thanks.

[@KERVERAS]

@grayfurnaceman Dear sir thanks for your video and the time & effort to share your knowledge.This is very valuable piece of information to visualise what is in there.

[@grayfurnaceman]

Welcome GFM

[@PlausableApple4]

Very informative! I learned a lot! Do you have explanations on how a an expansion/TXV valve works, and how a filter dryer works?

[@doddgarger6806]

That is a cool design

[@grayfurnaceman]

It is quite cool, but the early ones (in my father's days) took quite a while to get them to stop sticking. GFM

[@phillipolmeda8590]

Great video!

[@grayfurnaceman]

Thanks for the support. GFM

[@fathmasameer7523]

Dear sir what is the function of capillary tube in reversing valve?and thanks for helpful video thanks again .

[@grayfurnaceman]

The tubes connect from the pilot valve to the main valve to actuate the piston. Hope this helps. GFM

[@wagnersouza4912]

Good video, very helpful!

[@joselopez5252]

good explanation, thanks.

[@fktheharley]

THX GMF great video !!

[@Rattletrap2]

oops, I posted before I finished watching! lol You answered my question!

[@itsj1train]

Question for the center of the RV for the suction side, the "U" shape, is that plastic?

[@grayfurnaceman]

Yes it is. GFM

[@itsj1train]

grayfurnaceman thanks. I feel that may be where im getting the plastic junk in my metering device.