Tool List- www.amazon.com/shop/acservicetech Support- www.patreon.com/acservicetech For those that are looking for the tools used in the videos: (Linked Below) Here is the Link for the Yellow Jacket Refrigerant Manifold Gauge Set used in the videos amzn.to/2aenwTq Here is the link for the Ratcheting Service Wrench amzn.to/2dGV4Nh Here is a link to Refrigerant hoses with valves used in the videos amzn.to/2aBumVI Here is the Yellow Jacket Manifold Gauge Set including standard hoses- amzn.to/2vLVkV9 Here is the Yellow Jacket 4 Port Brute Manifold with Hoses- amzn.to/2BkuGIq Here is the Fieldpiece SMAN460 Digital Manifold Set- amzn.to/2nB4Fe6 Here is the Fieldpiece SMAN360 Digital Manifold Set- amzn.to/2BdoaD4 Here is the Compact Ball Valve Attachment for the end of the Refrigerant Hose- amzn.to/2KUisW8 Here is the Quick Disconnect 90 degree attachment for the end of the refrigerant hose- amzn.to/2MMtVcg Here is the link to the Fieldpiece ST4 Dual Temp Meter- amzn.to/2wc1ME3 Here is the link to the Appion Valve Core Removal Tool- amzn.to/2uYr8WL Here is a link to the JB 6 CFM Vacuum Pump amzn.to/2nqbvo8 Here is the Link to the Appion Blue 3/8" to 1/4" Vacuum Hose- amzn.to/2uYlVyc Here is the Link to the Appion Red 3/8" to 1/4" Vacuum Hose- amzn.to/2uYg6Ro Here is the link to the Yellow Jacket 1/4" by 1/4" heavy duty hose straight- amzn.to/2umtcod Here is the link to the CPS Vacuum Micron Gauge- amzn.to/2v1nM3O Here is the Link to the AccuTrak VPE Pro with Headphones- amzn.to/2B2cRO3 Here is a link for RectorSeal Bubble Gas Leak Detector amzn.to/2ckWACn Here is a link the Nitrogen Regulator amzn.to/2bXdR5f Here is a link to the Nitrogen Flow Meter amzn.to/2brvoBg Here is a link to the Digital Refrigerant Scale used amzn.to/2b9oXYl Other tool links can be found in the video description section. Shop through Amazon! Your Purchases through Amazon provide a means for channels such as mine to earn advertising fees from all purchases after clicking through. Prices are the same as normal- www.amazon.com/shop/acservicetech All of the ACSERVICETECH Playlists- th-cam.com/channels/OZR-1IqsAer9wzlvFgb4mA.htmlplaylists?view_as=public
Liqued line guge fixed sushion line pump down liqued line systom ruing and iqued line valve closecd sushion line valbe guge 0 comeing valve fullclosed ok pump down mether reparing any gas saveing after fixing purgeing amg cjecking systiomes ok
I work for the City and was thrown into HVAC over 7 years ago never went to school for it I was taught by my supervisor hands-on but I have learned the correct way of doing things by watching your videos. You provide more information than any other person I have watched or learned from.
Just followed this vid and pumped down my system (will be completely replacing system, furnace, condenser and A coil). Worked like a charm. I used the harbor freight gauge set, no issues at all. It goes very quick. For those interested, the liquid fitting allen is 3/16 and the vapor one is 5/16. I just used a set that fits on my ratchet, no issues.
Thank you Craig for the excellent videos!! I'm planning on doing my 1st pump down today and you gave me the confidence I needed. I highly recommend your book and cards to anyone reading this. You are a 5 star instructor!
A lot of times though these videos help consolidate information and help connect the dots in which you are learning in school. I just hope that the school is giving you the hands on portion, thanks!
Another clear and concise video ty so much for these videos they really help me out here in the boonies when i get stuck for help and im the only guy within a couple hundred miles that can help ppl out.
Can you elaborate how much Freon can be stored in the condenser coils? Example, usually more Freon is added for longer line sets, etc.. How do you know how much space you have before you have to use a recovery machine?
Easy to do is hook up a clean ecovery bottle up and just open the liquid line, take out half or whatever will easily go in, then pump down the rest and just throttle it back in the vapor side when youre done with whatever you needed to do and vacuumed your lines (and opened the valves ofc)
For a full change out can you just shut the discharge line down, attach your gauge to the suction side and run the comp until you hit zero on your gauge and shut the suction line down? Then just cut the lines and pull the condenser out.
Wonderful video! When we shut off the valve at the discharge line while keeping the valve at the suction line open, would also the pressure at the discharge line become zero? And after closing both valves for pump down operation, what would be the pressure at the condenser?
My hat off to you for this video. Excellent. You had already connected the manifold to the unit when you started the video. Did you let some gas out of the system to purge the hoses and manifold or did you use a vacuum pump?
Hey Craig, great video. I tried to pump down a two stage (with the heat pump valve energized). Gauges went down to 25psi for a few minutes then went back up.
Other than a microchannel being an indicator that you cannot pump down, do you need to look up manufacturer trouble shooting to see if you can pump down and operate the compressor in a vacuum? If so, wouldn't it be quicker to just recover the whole unit?
I'm a home owner and I have done a lot of work on my HVAC thanks to your lessons. Thank for the great information. I 'm dealing with a leak in the return line where there is a union in the cooper line that leads to the compressor. I think you mentioned in another video lesson not to ever do a pump down on a scroll compressor? I was wondering why? And would it be better to evacuate all refrigerant, braze the leak, do a vacuum test and lastly place the refrigerant back into the compressor.
@@lillithjones993 hello and greeting. Well, I ended up recharging the system with R22 refrigerant and the system works well. So far it has lasted three weeks but this is just a band-aid. I will try to teach myself how to evacuate all the refrigerant from the HVAC system, find the leak and braze it. Pressure test it and then put all the refrigerant back in it. I tried my best to find someone that would do all these steps but all technicians want to either pump the system with sealer or sell me another HVAC system. Please, whatever you do do not pump sealer into your HVAC system, it may cause problems in your compressor. Good luck with your issue, wish you the best.
@@grandmazinger73hopefully youve solved it by now but if not, use a refrigerant detector to find the leaking area and soapy water to pinpoint. Now you know what youre dealing with. If its a schrader valve you can get a tool to replace them under pressure. If not, if youve got the tools to evacuate, nitrogen test, braze etc you can fix it yourself anyway. Just purge the system with the nitrogen while you braze and youll be fine
Mr. Migliaccio, thank you for this demonstration of the pump down with the most important by-pass of the low-pressure switches and their relationship with the contactor switch, very important. I'm going to replace a TXV, air dryer and screen; however, I was not sure how to evacuate my system until I saw this video...Thank you..! I'm not an HVAC tech, just a homeowner DIY person. One last question?? Why does my AC system; when off for 14 or more hours, show 120psig on the liquid line and 45psig on the vapor line? I thought the values should be equal pressures; is this another method to prove I have a liquid line restriction..? Regards, Joseph
Do condensers with micro channel fins come pre-charged with R410a, and I’m asking, because you stated not to pump down condensers with micro channel fins.
I picked up an old R22 unit that was advertised as having about 4 lbs of Freon in it. The guy said the person pumped the system down into the outside condenser unit. The liquid and suction lines were cut and then pinched off, and the service valves were both closed. When I open the liquid side service valve, I can see it is under pressure. But when I open the suction side service valve and hook up a gauge, it reads zero. I even pulled the shrader out to make sure it was not blocked. Is this normal? I would think the pressures on high and low side would be equal? I wanted to pull the freon out to donate the unit to an HVAC school, but I'm confused as to what's going on. Thanks in advance for any advice.
I have a condenser that came that came with refrigerant for about 15ft of line, but extra long lines were installed 30ft and extra refrigerant added. Would the condenser have enough capacity to hold all the refrigerant after a pump down - or would it over pressurize? How should you deal with this situation...
Great video. Any feedback on how much more refrigerant a condenser can hold vs the factory fill (in case you need to pumpdown, say a 50' lineset)? I've read factory fill is about 80% of outdoor coil volume.
I wish my freaking job would teach my this. I’m over here having to freaking pull up yt vids to make sure I’m doing this right. Last time i pumped down was probably almost a year ago
After pumping down..and after doing a repair on the line set. Then, is it ok to just release the refrigerant back in the line set? and would the ac system work normal again?
What if before doing anything, you close the liquid line valve completely, then turn the unit on so the compressor can suck all the refrigerant into the condenser. And then close the suction line?
My heat pump system would not pump down when I simply pushed in the contactor switch (safely with a wooden paint stirrer). I didn't want to mess with the wires to bypass the pressure sensors, so I used the contactor switch method. When I went to the thermostat to call for cool as a last resort, it pumped down in a bout 60 seconds! Why? Thank you.
Hi, I wanted to see if you had advice on performing a pump down when the indoor unit control board has failed? In other words, the indoor unit does not operate, so the only way to turn the compressor on is to hold in the contactor. Should I point a space heater on a low setting blowing at the indoor coil or something like that? EDIT: I should clarify, I'm dealing with a mini split/ductless, not central air.
Question , I have a 3 tons heat pump, the txv will be replace and in order to do that the refrigerant will be recover, the question is IF I CAN pump down as much 410a in the condenser and recover the rest and later charge again using the. Su cooling method ? It’s a building and the line set is about 70 feet long.
Great video. Got a question. We have a cracked concrete under the ac unit and needs a replacement. It is removable concrete. If you have two people lifting the ac unit up and one person changing the concrete do you still need to pump down and cutting wires and other stuff that is connected?
nice video Craig. what if the system had a leak in it say the line set and most the refrigerant leaked out is a pump down still required or should the system be put in a vacuum to remove any contaminants even tho a leak is present say on the line set/valve port where the line set goes in or should the leak be brazed while obviously using 3psi of air ... fix the leak then go ahead pulling it in a vacuum and re check for a leak ? and also should we the vacuum be left on for a specific amount of time to pull out as many contaminants as possible?
A little confused regarding doing a pump down to fix a leak. You said if you pump down to a vacuum on the liquid line it will draw air into the system so only pump down to about 5.psig,, and then use an external recovery machine to remove the remaining refrigerant. I get that doing the pump down to negative psig will draw air through the leak into the line set, however, I don't understand why drawing a negative vacuum using an external vacuum compressor is any different? A vacuum is a vacuum and air will be drawn in no matter what compressor is used I would think?
Pump downs are not good for any compressor so if you need to do it, it should be quick. Reciprocating and scroll both use the oil with refrigerant flow to lubricate and the refrigerant flow to cool. The scrolls have tighter electrical clearances to ground and the lack of refrigerant for insulation is not helpful for sure. Some larger scrolls have a low pressure cutout but typically smaller residential ones don't. I would not argue that it is not good for the scroll compressor to be pumped down into a vacuum. Pump downs are better when done on reciprocating, thanks Steven!
Great vid AC Service Tech: So pretty sure I've seen in print somewhere that Goodman says DO NOT pump down their residential Scroll/Heat pumps and wanted to understand why. You said "so if you need to do it, it should be quick", does that mean the disconnect pulled instantly after vapor valve front seated or if not what is meant by "quick"? Is it really harmful or just if going into vacuum that hurts? Is it more harmful to HP's vs. straight A/C condensers? I know both high and low ps's would need to be jumped out to get to 0 PSI but could you elaborate on best practices to get it pumped down without hurting the scroll compressor, as if it were your personal unit? What damage is done to the scroll comp. if done anyway or is Goodman just trying to scare techs?
First off, I would say to always follow manufacturers directions. It is my belief that they are speaking on when the inlet goes below 0psig. On scrolls, the electrical windings are very close to ground and when in vacuum, there is a reduction in insulation between the windings and the ground. Therefore potential arcing can occur and damage the windings of the motor during that time. If you are concerned or the unit or compressor you are working on states not to pump down, then don't. Maybe the unit you are referring to is a microchannel, not sure. You can always forward over the heat pump doc if you find it so I can try to figure out why. Most of the time manufacturers are mentioning about the time the compressor is in vacuum while running. If this is a concern on the particular unit you are working on then just pump the unit down to a level above 0psig such as 10 psi, shut the vapor valve, turn the unit off immediately following, and then recover the rest of the refrigerant. I just mean't that pump downs in general are not great for the compressors except those designed to do so on a regular basis such as in refrigeration. Pump downs for Condensors are usually the same for heat pumps on standard units. Make sure that the vapor valve is shut before turning off the unit though and make sure the tstat was in cooling. If you can't pump a unit down, then just shut the valves while off and recover the rest. Thanks Bobrub, I hope that helps!
bobrub. Iv pumped down scrolls a great many times (dispite the warning not to) And always gotten away with it. I just take care to stop promptly a bit above zero. I find the "bounce back " of evaporated gas is minimal. If you're practiced you got the timing right. Or if your worried do the following : stop promptly at about 20psi. Release the tiny remainder. After the repair, vac then fill to 20psi from a bottle. Then release valves as Normal. HTH The other safest way, use the recovery pump, pump into condensor.
I assume you need a certain gauge wire cuz I used a spade wire from an old heat coil with a spade and it wasn’t pulling in 24V constantly and cycled on and off
Hi there hopefully you get this, I have a split AC with a failed PCB. Can I directly power the compressor and follow this procedure for safe removal of the unit. I do not have a recovery system. Thanks kindly.
@@pack5eastnorthport366 Fuji- Spot on, how'd you know? What exactly was the PCB fault? I ended up directly running the compressor off a direct DC voltage matching the specs on it. So what I mentioned, worked for pumping the unit down safely.
Jess Harris hi Jess - sorry for the late response. Never found out the fault- tried testing the board as best I could to no avail. Three choices: buying new board from distributor (HVAC only), getting used board second hand (good luck), mailing to Module Repair Service in Australia to diagnose and repair (expect to wait a couple of months, plus shipping and a few hundred). The board will not look quite the same but it will work again. I’m pretty sure a power surge from turning breaker on and off killed our board. I replaced the breaker after putting the board back.
Hi Craig, I am a huge fan of your videos, but this time I really dont agree with this procedure, because at this point, no oil will come back to lubricate the compressor, and most importantly, the compressor won't be refrigerant cooled at this point ( high superheat ), I usually stop the pump down at +15 to +20 psig ( by the book just like the solenoid valve controled fridge compressors ), bcz I can lose this tiny vapor quantity in order to save the compressor longivity
I have a Carrier PH13 3-ton HP. Bypassed the pressure switch circuit and pumped down. Could only get it down to about 90psi. I repeated the procedure twice with the same result. Seems like the compressor just bypasses or something. There was very little gas remaining in system, so I'm guessing the coil just couldn't hold any more? I do have a 4-ton air handler, so maybe the overall system capacity with 4T indoor coil is too much for OD coil to store? Is that possible? Thanks for the great tips and any comment....just for curiosity.
I guess the channel has gone dormant, but either way everything worked out fine for me. Ended up adding about a 1lb after putting everything back together, FWIW. So I would call the pump down a success even if I couldn't achieve a vacuum during the pump down.
EPA 608 prep manual, page 23 top half says: "Under no circumstances should the discharge service valve be closed on an operating reciprocating compressor." Is a pump down an exception to this?
They are talking about the discharge service valve on the side of the compressor, not the liquid line service valve. You have the condenser coil to hold the refrigerant in that case, thanks!
Gotta have some units in the classroom that are junkers with recip compressors to train for the pump down. I had to have the students build and connect them.
If all the refrigerant it's being stored in the condenser coil shouldn't that increase the pressure in the high side? Why did the pressure in the high side went down? If someone could explain it to me I would really appreciate it
You can typically pump down a scroll compressor to 5 to 10 psi unless the manufacturer literature specifies not to. Reciprocating compressors can be completely pumped down usually, thanks!
AC Service Tech LLC, what's the point in doing a pump down when you have to use the recovery machine any if there is a leak, I thought the purpose of pump down was to have somewhere to put the refrigerant temporally to fix leaks, replace a TXV or piston without doing a full recovery?
Theres no point in doing a pump down if the leak is in the condenser. If the leak is elsewhere then you can just pump down the system and work on the lineset up to the indoor unit
It is better if you can shut the vapor valve before shutting power off so the that no vapor left in the compressor will increase the pressure on the lines after the pump down. Also if it is a heat pump then you wouldn't have a choice. The vapor valve must be shut before the power is turned off because the reversing valve would allow the refrigerant to come back out, thanks and yes it is just a little harder to time the closing of the vapor valve, thanks!
hi, i was wondering why on some units doing a pump down by pressing down on the contactor the compressor keeps shutting down after 2 or 3 seconds? but on other units it works fine. thank you.
That would have to do with a low pressure and high pressure switch. You would need to bypass them in order to pump a unit down. Look up"acservicetech pressure switches" thanks!
but if you were to press the contactor down all the time wouldn't this bypass the low/high pressure switch? if the low/high pressure switch were to trigger it should not affect the contactor because you're holding the contactor down all the time. please correct me if i am wrong . thank you again for all your help.
I am sorry I read and answered too quick. You are correct. So is thecompressor making a loud noise and continuing to run or is it literally shutting off on you? Are you loosing 240v at this time? The only thing I am thinking of is either the internal overload or the pressure relief
the compressor just shuts down. compressor just shuts down after 2 or 3 seconds into pump down. i've tried again and again and the same thing happens. thank you.
yes it does sounds like pressure relief . the compressor makes a sound PSSSSSSSSSSSSS and then shuts down. then when i tried again it pumps down for 2 or 3 seconds and then PSSSSSSSSSSSS and shuts down again. what would cause the pressure relief to go off like that? thanks.
Hey JiggyPatel, the pump down is used when you are moving the outdoor unit or fixing a leak in the lineset or indoor coil and you are trying to lock all of the refrigerant that was in the system into the outdoor unit just like the unit comes from the factory like unless it is a dry unit. We try to get all of the refrigerant into the outdoor until in one shot so recovery is not needed. If the unit has a leak then don't pump down below 0psig. Thanks JiggyPatel!
Hey ejcsds, basically after fixing the leak with the valve cores out, pressure test, nitrogen blowout, vacuum to 200-300 microns and then break the vacuum with vapor valve since this was a carrier unit. Some equipment manufacturers want the vacuum broke by opening the high side. Thanks for letting me know what you would like to see ejcsds!
Tool List- www.amazon.com/shop/acservicetech
Support- www.patreon.com/acservicetech
For those that are looking for the tools used in the videos: (Linked Below)
Here is the Link for the Yellow Jacket Refrigerant Manifold Gauge Set used in the videos amzn.to/2aenwTq
Here is the link for the Ratcheting Service Wrench amzn.to/2dGV4Nh
Here is a link to Refrigerant hoses with valves used in the videos amzn.to/2aBumVI
Here is the Yellow Jacket Manifold Gauge Set including standard hoses- amzn.to/2vLVkV9
Here is the Yellow Jacket 4 Port Brute Manifold with Hoses- amzn.to/2BkuGIq
Here is the Fieldpiece SMAN460 Digital Manifold Set- amzn.to/2nB4Fe6
Here is the Fieldpiece SMAN360 Digital Manifold Set- amzn.to/2BdoaD4
Here is the Compact Ball Valve Attachment for the end of the Refrigerant Hose- amzn.to/2KUisW8
Here is the Quick Disconnect 90 degree attachment for the end of the refrigerant hose- amzn.to/2MMtVcg
Here is the link to the Fieldpiece ST4 Dual Temp Meter- amzn.to/2wc1ME3
Here is the link to the Appion Valve Core Removal Tool- amzn.to/2uYr8WL
Here is a link to the JB 6 CFM Vacuum Pump amzn.to/2nqbvo8
Here is the Link to the Appion Blue 3/8" to 1/4" Vacuum Hose- amzn.to/2uYlVyc
Here is the Link to the Appion Red 3/8" to 1/4" Vacuum Hose- amzn.to/2uYg6Ro
Here is the link to the Yellow Jacket 1/4" by 1/4" heavy duty hose straight- amzn.to/2umtcod
Here is the link to the CPS Vacuum Micron Gauge- amzn.to/2v1nM3O
Here is the Link to the AccuTrak VPE Pro with Headphones- amzn.to/2B2cRO3
Here is a link for RectorSeal Bubble Gas Leak Detector amzn.to/2ckWACn
Here is a link the Nitrogen Regulator amzn.to/2bXdR5f
Here is a link to the Nitrogen Flow Meter amzn.to/2brvoBg
Here is a link to the Digital Refrigerant Scale used amzn.to/2b9oXYl
Other tool links can be found in the video description section.
Shop through Amazon! Your Purchases through Amazon provide a means for channels such as mine to earn advertising fees from all purchases after clicking through. Prices are the same as normal- www.amazon.com/shop/acservicetech
All of the ACSERVICETECH Playlists- th-cam.com/channels/OZR-1IqsAer9wzlvFgb4mA.htmlplaylists?view_as=public
AC Service Tech LLC what brand of vacuum pump did I hear on that video?? It sounds like a central air conditioner
Thankyou pump down firest dis chareged closef afyer ruinng time sevnd guged preshare 0 ,,, comeing closed ok after valved closed pk thankyou
Liqued line guge fixed sushion line pump down liqued line systom ruing and iqued line valve closecd sushion line valbe guge 0 comeing valve fullclosed ok pump down mether reparing any gas saveing after fixing purgeing amg cjecking systiomes ok
I work for the City and was thrown into HVAC over 7 years ago never went to school for it I was taught by my supervisor hands-on but I have learned the correct way of doing things by watching your videos. You provide more information than any other person I have watched or learned from.
JD, that is so awesome, thanks!
So am I, I have learned a lot by watching his videos and some other people.....👍👍
Their book on Amazon is very helpful as well.
Love the content thank you
@@Honestandtruth007what are some other good HVAC educational channels?
HVAC school.
Just followed this vid and pumped down my system (will be completely replacing system, furnace, condenser and A coil). Worked like a charm. I used the harbor freight gauge set, no issues at all. It goes very quick. For those interested, the liquid fitting allen is 3/16 and the vapor one is 5/16. I just used a set that fits on my ratchet, no issues.
I've learned more through this channel than the year of school I went through. Such a great channel!
Wow, thank you!
Thank you Craig for the excellent videos!! I'm planning on doing my 1st pump down today and you gave me the confidence I needed.
I highly recommend your book and cards to anyone reading this. You are a 5 star instructor!
I love the way you explain the reason why..instead of just because.. Great video..!
I appreciate that!
Thank you for the great information it’s sad that I am going to school. And I have learned more from this channel than school
A lot of times though these videos help consolidate information and help connect the dots in which you are learning in school. I just hope that the school is giving you the hands on portion, thanks!
Damn had to watch this multiple times to soak in all the gems. Some new information I got every time! Thanks so much for this video!
Thanks so much for this one. Straight and to the point. I have said it a million times before, On one can teach as good as you Sir.
Thank you very very much Drifter436!
Amazing information sir, when I did installs I always did the outdoor unit this was the first step to installing a new one to begin with
Excellent video! Thanks. Probably the best step-by-step video out there.
Thanks you very much Roger!
Another clear and concise video ty so much for these videos they really help me out here in the boonies when i get stuck for help and im the only guy within a couple hundred miles that can help ppl out.
Thanks, my AC may need a new filter drier and is good to know the proper procedure.
Can you elaborate how much Freon can be stored in the condenser coils? Example, usually more Freon is added for longer line sets, etc.. How do you know how much space you have before you have to use a recovery machine?
Easy to do is hook up a clean ecovery bottle up and just open the liquid line, take out half or whatever will easily go in, then pump down the rest and just throttle it back in the vapor side when youre done with whatever you needed to do and vacuumed your lines (and opened the valves ofc)
Great tip on the micro-channel. Not enough room to store the refrigerant.
Thanks Danny!
Thank you brother so appreciate you so very much for the demonstration.
About to do my first pump down being in the field 2.5 years.
Your video really help me so now am ready to do a pump down
Nice job Sir. Well demonstrated.
Glad you liked it!
For a full change out can you just shut the discharge line down, attach your gauge to the suction side and run the comp until you hit zero on your gauge and shut the suction line down? Then just cut the lines and pull the condenser out.
Excellent video and explanation.
thank you, I always know I can find a video on something I need for the trade.
Glad I could help
Very very good video 1 million thumbs up thank you so much
So nice of you
Wonderful video! When we shut off the valve at the discharge line while keeping the valve at the suction line open, would also the pressure at the discharge line become zero? And after closing both valves for pump down operation, what would be the pressure at the condenser?
My hat off to you for this video. Excellent. You had already connected the manifold to the unit when you started the video. Did you let some gas out of the system to purge the hoses and manifold or did you use a vacuum pump?
Do you have a pump down video on a mini split unit? Thanks
Well, good thing *someone* watched this before pumping down a micro coil condenser...
If there was a vapourized liquid in the system after the pump down, what action should I take?
Hey Craig, great video. I tried to pump down a two stage (with the heat pump valve energized). Gauges went down to 25psi for a few minutes then went back up.
You would need to bypass the low pressure switch, thanks!
What do you mean by "front seating" 7:17 ... (applying pressure? guessing) great video
Can you show a pump down procedure on a condensing unit with a three position service valve?
Other than a microchannel being an indicator that you cannot pump down, do you need to look up manufacturer trouble shooting to see if you can pump down and operate the compressor in a vacuum?
If so, wouldn't it be quicker to just recover the whole unit?
I'm a home owner and I have done a lot of work on my HVAC thanks to your lessons. Thank for the great information. I 'm dealing with a leak in the return line where there is a union in the cooper line that leads to the compressor. I think you mentioned in another video lesson not to ever do a pump down on a scroll compressor? I was wondering why? And would it be better to evacuate all refrigerant, braze the leak, do a vacuum test and lastly place the refrigerant back into the compressor.
I have the very same problem. The installer would not come back and fix it. What did you end up doing?
@@lillithjones993 hello and greeting.
Well, I ended up recharging the system with R22 refrigerant and the system works well. So far it has lasted three weeks but this is just a band-aid. I will try to teach myself how to evacuate all the refrigerant from the HVAC system, find the leak and braze it. Pressure test it and then put all the refrigerant back in it. I tried my best to find someone that would do all these steps but all technicians want to either pump the system with sealer or sell me another HVAC system. Please, whatever you do do not pump sealer into your HVAC system, it may cause problems in your compressor. Good luck with your issue, wish you the best.
@@grandmazinger73hopefully youve solved it by now but if not, use a refrigerant detector to find the leaking area and soapy water to pinpoint. Now you know what youre dealing with. If its a schrader valve you can get a tool to replace them under pressure.
If not, if youve got the tools to evacuate, nitrogen test, braze etc you can fix it yourself anyway. Just purge the system with the nitrogen while you braze and youll be fine
Hi,
Why did the low side gauge reach 0 psig first. Wouldn't it be the other way around?
Mr. Migliaccio, thank you for this demonstration of the pump down with the most important by-pass of the low-pressure switches and their relationship with the contactor switch, very important. I'm going to replace a TXV, air dryer and screen; however, I was not sure how to evacuate my system until I saw this video...Thank you..! I'm not an HVAC tech, just a homeowner DIY person. One last question?? Why does my AC system; when off for 14 or more hours, show 120psig on the liquid line and 45psig on the vapor line? I thought the values should be equal pressures; is this another method to prove I have a liquid line restriction..? Regards, Joseph
Is it safe to remove the red hose after pump down, or will refrigerant come out of the service port?
Do condensers with micro channel fins come pre-charged with R410a, and I’m asking, because you stated not to pump down condensers with micro channel fins.
Yes but if extra refrigerant was added into the system after installation we don't want to force that into the small micro channel, thanks!
@@acservicetechchannel So just recover then add back when repairs are done
Well done keep up the good work
Thanks ejohnfall!
Thanks from Australia mate!
Awesome, thanks Kevin!
I picked up an old R22 unit that was advertised as having about 4 lbs of Freon in it. The guy said the person pumped the system down into the outside condenser unit. The liquid and suction lines were cut and then pinched off, and the service valves were both closed. When I open the liquid side service valve, I can see it is under pressure. But when I open the suction side service valve and hook up a gauge, it reads zero. I even pulled the shrader out to make sure it was not blocked. Is this normal? I would think the pressures on high and low side would be equal? I wanted to pull the freon out to donate the unit to an HVAC school, but I'm confused as to what's going on. Thanks in advance for any advice.
good, i was looking for pressure switch bypass for pump down
I have a condenser that came that came with refrigerant for about 15ft of line, but extra long lines were installed 30ft and extra refrigerant added. Would the condenser have enough capacity to hold all the refrigerant after a pump down - or would it over pressurize? How should you deal with this situation...
Thank you for sharing this video.
Great video. Any feedback on how much more refrigerant a condenser can hold vs the factory fill (in case you need to pumpdown, say a 50' lineset)? I've read factory fill is about 80% of outdoor coil volume.
Buy the book.. read then watch the vid. Thank you much migliaccio!!!!
Thanks so much Ben!!
I wish my freaking job would teach my this. I’m over here having to freaking pull up yt vids to make sure I’m doing this right. Last time i pumped down was probably almost a year ago
Did this unit have a scroll type compressor?
After pumping down..and after doing a repair on the line set. Then, is it ok to just release the refrigerant back in the line set? and would the ac system work normal again?
No it needs the pressure test, vacuum, and standing vacuum test first, thanks
What if before doing anything, you close the liquid line valve completely, then turn the unit on so the compressor can suck all the refrigerant into the condenser. And then close the suction line?
The compressor could have a hard time starting up thats all. I leave the liquid line open until the compressor starts fully, thanks!
Good deal I forgot about that low pressure switch oh, it was stopping me from pumping it down.
My heat pump system would not pump down when I simply pushed in the contactor switch (safely with a wooden paint stirrer). I didn't want to mess with the wires to bypass the pressure sensors, so I used the contactor switch method. When I went to the thermostat to call for cool as a last resort, it pumped down in a bout 60 seconds! Why? Thank you.
So what is the procedure for releasing the refrigerant back into the line set?
First video I’ve seen that mentions the refrigerant is stored in the condenser. Thank your for the detail in explaining the full process.
Thanks Cruz!
Hi, I wanted to see if you had advice on performing a pump down when the indoor unit control board has failed? In other words, the indoor unit does not operate, so the only way to turn the compressor on is to hold in the contactor. Should I point a space heater on a low setting blowing at the indoor coil or something like that? EDIT: I should clarify, I'm dealing with a mini split/ductless, not central air.
Question , I have a 3 tons heat pump, the txv will be replace and in order to do that the refrigerant will be recover, the question is IF I CAN pump down as much 410a in the condenser and recover the rest and later charge again using the. Su cooling method ? It’s a building and the line set is about 70 feet long.
Great video. Got a question. We have a cracked concrete under the ac unit and needs a replacement. It is removable concrete. If you have two people lifting the ac unit up and one person changing the concrete do you still need to pump down and cutting wires and other stuff that is connected?
when your pumping down you are going clockwise correct?
@acservicetechchannel what if I have a bad/restricted TXV will I still be able to achieve a pump down?
Do they teach pumpdowns in their book?
You are awesome!!!! Great video.
Thanks a lot How To Do It!
Great Info. Thanks for sharing
Thanks a lot DeanMartin! First Comment!
Thanks. Its good to be first. Lol
nice video Craig. what if the system had a leak in it say the line set and most the refrigerant leaked out is a pump down still required or should the system be put in a vacuum to remove any contaminants even tho a leak is present say on the line set/valve port where the line set goes in or should the leak be brazed while obviously using 3psi of air ... fix the leak then go ahead pulling it in a vacuum and re check for a leak ? and also should we the vacuum be left on for a specific amount of time to pull out as many contaminants as possible?
A little confused regarding doing a pump down to fix a leak. You said if you pump down to a vacuum on the liquid line it will draw air into the system so only pump down to about 5.psig,, and then use an external recovery machine to remove the remaining refrigerant. I get that doing the pump down to negative psig will draw air through the leak into the line set, however, I don't understand why drawing a negative vacuum using an external vacuum compressor is any different? A vacuum is a vacuum and air will be drawn in no matter what compressor is used I would think?
Can it be done on a Scroll? I was under the impression that it can just not into a vacuum.
Pump downs are not good for any compressor so if you need to do it, it should be quick. Reciprocating and scroll both use the oil with refrigerant flow to lubricate and the refrigerant flow to cool. The scrolls have tighter electrical clearances to ground and the lack of refrigerant for insulation is not helpful for sure. Some larger scrolls have a low pressure cutout but typically smaller residential ones don't. I would not argue that it is not good for the scroll compressor to be pumped down into a vacuum. Pump downs are better when done on reciprocating, thanks Steven!
Great vid AC Service Tech: So pretty sure I've seen in print somewhere that Goodman says DO NOT pump down their residential Scroll/Heat pumps and wanted to understand why.
You said "so if you need to do it, it should be quick", does that mean the disconnect pulled instantly after vapor valve front seated or if not what is meant by "quick"?
Is it really harmful or just if going into vacuum that hurts?
Is it more harmful to HP's vs. straight A/C condensers?
I know both high and low ps's would need to be jumped out to get to 0 PSI but could you elaborate on best practices to get it pumped down without hurting the scroll compressor, as if it were your personal unit?
What damage is done to the scroll comp. if done anyway or is Goodman just trying to scare techs?
First off, I would say to always follow manufacturers directions. It is my belief that they are speaking on when the inlet goes below 0psig. On scrolls, the electrical windings are very close to ground and when in vacuum, there is a reduction in insulation between the windings and the ground. Therefore potential arcing can occur and damage the windings of the motor during that time. If you are concerned or the unit or compressor you are working on states not to pump down, then don't. Maybe the unit you are referring to is a microchannel, not sure. You can always forward over the heat pump doc if you find it so I can try to figure out why. Most of the time manufacturers are mentioning about the time the compressor is in vacuum while running. If this is a concern on the particular unit you are working on then just pump the unit down to a level above 0psig such as 10 psi, shut the vapor valve, turn the unit off immediately following, and then recover the rest of the refrigerant. I just mean't that pump downs in general are not great for the compressors except those designed to do so on a regular basis such as in refrigeration. Pump downs for Condensors are usually the same for heat pumps on standard units. Make sure that the vapor valve is shut before turning off the unit though and make sure the tstat was in cooling. If you can't pump a unit down, then just shut the valves while off and recover the rest. Thanks Bobrub, I hope that helps!
bobrub. Iv pumped down scrolls a great many times (dispite the warning not to) And always gotten away with it. I just take care to stop promptly a bit above zero. I find the "bounce back " of evaporated gas is minimal. If you're practiced you got the timing right.
Or if your worried do the following : stop promptly at about 20psi. Release the tiny remainder. After the repair, vac then fill to 20psi from a bottle. Then release valves as Normal. HTH
The other safest way, use the recovery pump, pump into condensor.
I assume you need a certain gauge wire cuz I used a spade wire from an old heat coil with a spade and it wasn’t pulling in 24V constantly and cycled on and off
Hi there hopefully you get this,
I have a split AC with a failed PCB.
Can I directly power the compressor and follow this procedure for safe removal of the unit. I do not have a recovery system.
Thanks kindly.
That a Fuji? Also had a failed PCB....waited a few months to get it repaired. Working again.
@@pack5eastnorthport366 Fuji- Spot on, how'd you know? What exactly was the PCB fault?
I ended up directly running the compressor off a direct DC voltage matching the specs on it. So what I mentioned, worked for pumping the unit down safely.
Jess Harris hi Jess - sorry for the late response. Never found out the fault- tried testing the board as best I could to no avail. Three choices: buying new board from distributor (HVAC only), getting used board second hand (good luck), mailing to Module Repair Service in Australia to diagnose and repair (expect to wait a couple of months, plus shipping and a few hundred). The board will not look quite the same but it will work again. I’m pretty sure a power surge from turning breaker on and off killed our board. I replaced the breaker after putting the board back.
Can you restart the compressor to get any residual vapor that might have been in the evaporator coil?
No, you would need to recover that if you were not able hold a vacuum level and the pressure rose, thanks!
The small split don't have high and low pressure switch so I just start the ac close the high side and when it reaches into vacuum I stop thanks
Hi Craig, I am a huge fan of your videos, but this time I really dont agree with this procedure, because at this point, no oil will come back to lubricate the compressor, and most importantly, the compressor won't be refrigerant cooled at this point ( high superheat ), I usually stop the pump down at +15 to +20 psig ( by the book just like the solenoid valve controled fridge compressors ), bcz I can lose this tiny vapor quantity in order to save the compressor longivity
Good job
I have a Carrier PH13 3-ton HP. Bypassed the pressure switch circuit and pumped down. Could only get it down to about 90psi. I repeated the procedure twice with the same result. Seems like the compressor just bypasses or something. There was very little gas remaining in system, so I'm guessing the coil just couldn't hold any more? I do have a 4-ton air handler, so maybe the overall system capacity with 4T indoor coil is too much for OD coil to store? Is that possible? Thanks for the great tips and any comment....just for curiosity.
I guess the channel has gone dormant, but either way everything worked out fine for me. Ended up adding about a 1lb after putting everything back together, FWIW. So I would call the pump down a success even if I couldn't achieve a vacuum during the pump down.
What should the gauge pressure show of a pumped down unit in case I want to buy a used unit and need to be sure enough gas has been recovered.
Dude right on great stuff
Thanks Loccdogrms92!
Thank you.
EPA 608 prep manual, page 23 top half says: "Under no circumstances should the discharge service valve be closed on an operating reciprocating compressor." Is a pump down an exception to this?
They are talking about the discharge service valve on the side of the compressor, not the liquid line service valve. You have the condenser coil to hold the refrigerant in that case, thanks!
Great video keep them coming. Any heat pump vids in the future.
I would like to do some in the future, thanks Mike! Here is the Heat Pump troubleshooting playlist, thanks- th-cam.com/video/qiAOvJhq8_s/w-d-xo.html
Why you bypass the pressure switch as you could let the compressor run and lock down on low pressure?
Do you turn off the unit after pump down?
When you pump freon into a storage tank. You are not boiling off the freon.
Just did my first pump down I class today, I had to force my instructor to do this he said a drill can be better
Gotta have some units in the classroom that are junkers with recip compressors to train for the pump down. I had to have the students build and connect them.
Do all 410A have microfins or is it just not recommended to pump down on ones that have microfens
Thank you
When you have the system pumped down and opened for repair can you change both shrader valves since both lines are front seated?
Isn’t it funny how AC companies expect a new tech to pump a system down without ever doing it before? Just did my first today, thanks for the help.
Wow interesting. I would not want a new tech pressing in on the contactor and would want to show before they preform the task, thanks!
what refrigerant was in?
Always a great job Craig! Thank You!
Thanks for listening
Great video.You do a Great job of teaching.😜
Thanks a lot Phillip!
If all the refrigerant it's being stored in the condenser coil shouldn't that increase the pressure in the high side? Why did the pressure in the high side went down? If someone could explain it to me I would really appreciate it
Can i pump down 410a refrigerant?
Warum nicht? Klar, der Druck ist halt etwas höher.
You can typically pump down a scroll compressor to 5 to 10 psi unless the manufacturer literature specifies not to. Reciprocating compressors can be completely pumped down usually, thanks!
Exlent job..sir
AC Service Tech LLC, what's the point in doing a pump down when you have to use the recovery machine any if there is a leak, I thought the purpose of pump down was to have somewhere to put the refrigerant temporally to fix leaks, replace a TXV or piston without doing a full recovery?
Theres no point in doing a pump down if the leak is in the condenser. If the leak is elsewhere then you can just pump down the system and work on the lineset up to the indoor unit
What about releasing the freon back into the lines? Suction or liquid first?
Wondering this as well
AFTER nitrogen pressure test and drawing vacuum, crack the suction line first
If there is no pressure test port on low side how do you know its all pumped down
Last pump down video I saw, you shut off the power at the disconnect before closing the low side service port. Which is the preferred method?
It is better if you can shut the vapor valve before shutting power off so the that no vapor left in the compressor will increase the pressure on the lines after the pump down. Also if it is a heat pump then you wouldn't have a choice. The vapor valve must be shut before the power is turned off because the reversing valve would allow the refrigerant to come back out, thanks and yes it is just a little harder to time the closing of the vapor valve, thanks!
hi, i was wondering why on some units doing a pump down by pressing down on the contactor the compressor keeps shutting down after 2 or 3 seconds? but on other units it works fine. thank you.
That would have to do with a low pressure and high pressure switch. You would need to bypass them in order to pump a unit down. Look up"acservicetech pressure switches" thanks!
but if you were to press the contactor down all the time wouldn't this bypass the low/high pressure switch? if the low/high pressure switch were to trigger it should not affect the contactor because you're holding the contactor down all the time. please correct me if i am wrong . thank you again for all your help.
I am sorry I read and answered too quick. You are correct. So is thecompressor making a loud noise and continuing to run or is it literally shutting off on you? Are you loosing 240v at this time? The only thing I am thinking of is either the internal overload or the pressure relief
the compressor just shuts down. compressor just shuts down after 2 or 3 seconds into pump down. i've tried again and again and the same thing happens. thank you.
yes it does sounds like pressure relief . the compressor makes a sound PSSSSSSSSSSSSS and then shuts down. then when i tried again it pumps down for 2 or 3 seconds and then PSSSSSSSSSSSS and shuts down again. what would cause the pressure relief to go off like that? thanks.
How come my ac can’t pump down?
Any stuck/clogged up?
Can you recover the refrigerant and use it back when it have dye inside?
Sir dx seytam pump down after that cabrelly bolck please answer
Did you already recover the refrigerant that was in the system before you start the pump down. ?
JiggyPatel no the point is to get most refrigerant into condenser so u dont have much if any to recover
Hey JiggyPatel, the pump down is used when you are moving the outdoor unit or fixing a leak in the lineset or indoor coil and you are trying to lock all of the refrigerant that was in the system into the outdoor unit just like the unit comes from the factory like unless it is a dry unit. We try to get all of the refrigerant into the outdoor until in one shot so recovery is not needed. If the unit has a leak then don't pump down below 0psig. Thanks JiggyPatel!
William, thanks for answering the question for JiggyPatel!
AC Service Tech LLC so when do you do full recovery method ?
If the outdoor unit has a leak, part replaced, or needs to be replaced or the whole system needs to be replaced, thanks JiggyPatel!
Ac run but not cool air blow
All condenser fence, compressor running, enough freon but blow no cool air
Please advise
Can you now do the after repair video restart?
Hey ejcsds, basically after fixing the leak with the valve cores out, pressure test, nitrogen blowout, vacuum to 200-300 microns and then break the vacuum with vapor valve since this was a carrier unit. Some equipment manufacturers want the vacuum broke by opening the high side. Thanks for letting me know what you would like to see ejcsds!