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Intro to the HVAC vacuum pump part 1
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- Опубликовано: 30 июл 2013
- This the first in the Vacuum pump series.
This video is part of the heating and cooling series of training videos made to accompany my websites: www.graycoolingman.com and www.grayfurnaceman.com to pass on what I have learned in many years of service and repair. If you have suggestions or comments they are welcome.
If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal, the fuels are highly flammable and high pressures are used. Know your limits.
Hi. In a world full of under-exposed, noisy, awful sales pitches disguised as HVAC "how-to" videos, you produce high quality and informative content. Thanks so much!
batwingedloony Thanks for the comment. I try to use the best cameras but not all are perfect.
GFM
Great video about vacuum pump basics! I'm definitely with you about the size and accessories. Doesn't need to be too big, doesn't need an isolator valve or gauge built into the pump. It just so happens I have that exact same pump and have been very happy with it! I find that when you're evacuating a large system; it's probably an overnight affair anyways. Therefore, the pumps size dosen't really matter. Clean oil is really important, too. A lot of people don't believe it...
Question...do I need to leave the exhaust cap cracked open a bit during operation?
Thank you Sir...... Im drinking too.. so I can Understand you ....Great Class ...You Sound Like a AC teacher when you speak ... Thank you
good thorough explanation as always! ive got an older version of the robinair vacumaster its an 8 cfm and its provided me with about 8 years of trouble free service so far (knock on wood) keep the oil changed and they last a long time!
Great video, very informative. can't wait for the part 2.
You got Covid in 2013, subscribed...
Thanks for the support and here here on the oil change.
GFM
Thanks for the support
GFM
It all depends on the pump. You may notice the pump I am using is down to the lower third, but when started it goes to above 2/3ds. I would runs yours to where it does not pump oil.
GFM
Great video, very informative. can't wait for the next one
Thanks for the support.
GFM
Thanks for the video, in the market for a new vacuum pump and I will buy one like yours. I do not need bells and whistles.
I have a test on how to put our gauges on a system, how to recover refrigerant, pressure charge with Nitrogen and then Charging the system with refrigerant in our own words. Here what the handout says but I feel it could be way more detailed. If I was given this in the field and never done it before I am not sure if it would be good enough:
Installing Gauges
1. Remove valve system caps
2. Check that service valves are back seated
3. Remove access caps and Install gauges
4. Crack service valves off the back seat
5.Turn system on
5. You are now ready to record pressure
Recovering Refrigerant
1. Install gauges on refrigeration system
2. Attach yellow service hose on our gauges to inlet of recover unit
3.Use a second yellow hose and attach one end to the outlet of the recovery unit and the other end to a recovery cylinders liquid valve.
4. Open the low side of our gauges and allow refrigerant to flow through the recovery unit and out to the recovery cylinder.
5. Back off the hose connected to the recovery cylinder liquid valve just long enough for any air to escape and tighten the hose back up to the liquid valve
6. Open the valves on the recovery unit
7.Turn the recovery unit on and throttle your low side gauge until there is only vapor in the system then open bot high and low sides of your gauges fully.
8. Run the recovery unit until the refrigeration system is in a 20hg vacuum close your gauges both high and low side.
9. Close the liquid on the recovery cylinder and turn off the recovery unit.
10. Remove the recovery unit and cylinder and procceed with your repair.
Charging a Refrigeration System
1. Install your gauges if they are not already on the system
2. Hook one end of the micron gauge to the yellow service hose on your gauges.
3. hook the 3/8 hose on our gauges to the vacuum pump.
4. Turn the vacuum pump on and open both low and high sides of your gauges.
5. Leave the system on a vacuum until you reach a vacuum of 500 microns.
6. When 500 microns is reached close all the ports to your gauges.
7. Turn off the vacuum pump and remove the yellow hose from the pump and the micron gauge then put them away.
8. Hook your yellow service hose up to the vapor side of the refrigerant cylinder or recovery cylinder containing the refrigerant required for your system. Place on scale.
9. Open the vapor valve on the cylinder and then open the low side of your gauges until you see your system pressure reaches about 5 psig
10. Turn your gauges off and start your system then open the low side of your gauges and charge the amount of refrigerant the system requires.
11. Turn your low side gauge off and call your instructor over at this point to check your progress.
Removing Gauges
1. Back seat discharge service valve.
2.Cross purge gauges
3. Back seat suction service valve.
4. Turn system off.
5. Remove gauges and install caps.
Brent Peluso I would add to purge all hoses on installing gauges. This is assuming you have true service valves and not the valves used on most air conditioners.
As for recovery, looks pretty good, I open both valves and throttle. Also most recovery machines will shut down on low pressure at 15 in mercury.
Evacuation: I like to set the micron gauge at a service port farthest from the gauge hoses.
500 microns is not always possible. I look for a settled vacuum. I would do a triple evac.
Charging: This one requires a lot more than that. This is the hardest part. There are many ways to charge. Weight, superheat and sub cool, target superheat, manufacturer's charts, etc.
Overall, not too bad except for the charging part.
GFM
Ok thank you. How do I cross purge after I back seat the discharge service valve before removing my gauges
This is in class so we have stem type servicd valves that we have to Back Seat, Crack of the back seat, and Front Seat with our Refrigeration service wrench.
Love this video - thanks very much!
+Dwayne Dixon Welcome
GFM
Thanks will try that and run it a bit lower I was thiniking that I should fill it at or a bit higher than the fill line as to not cause adage to the pump but I seem to have excess oil in the gauges and hoses then my micron gauge acts up
it has 4 cables which go to which theres 3 red one black
ayeeee i need you fast i broke my dads it broke from the handle and sum black lil cylinder type thing came off how do i put it back
Some fan motors will put a surge in the circuit upon shutdown. That sometimes makes a klunking noise. Other than that, you might send a video with the sound.
GFM
great video. thanks
My question is, do you favor any brand of vac pump over another, and if so which one?
hi,good night,can you made a video on a Annie hermetic compressor analyser,? it will be appreciated,tks
Is it better to fill the oil to below the line? It seems with my bullet I fill to the line and when I run the pump the oil gets into the hose excessively and my sight window is covered full up. Great series look forward to #2
GOT IT, Thank you sir.
Thanks you, good educational video. I have a question: what should be the industrial standard for proper good vacuum, 500 or 250 Micron. Also is it the size of the equipment being evacuated, the HP of the pump, length , diameter of hoses and the cleanliness of the piping . will have a direct effect the time and the level of vacuum in micron gauge. Thanks for your help!!!!.
500 is what we shoot for. Some say 250, but this is only on new equipment and sometimes not then. So, can you get 500? Many times no. If the system has leaked out the refrigerant, had a compressor burnout or is quite large, you will be lucky to get 1000. Especially if it is 410A. Don't waste your time trying for something you can't get. Hope this helps.
GFM
Sir I have a question...when a unit (residential 3/4 ton) is being replaced, do we need to used the vacuum pump? I'm concerned about air getting into the lines/pump, My unit is being replaced because it very old and leaking.
+freddie sims If it is a split system with piping between the indoor coil and the outdoor unit, yes.
GFM
What happens if you put the oil in the discharge area (exhaust port) that has the big letters that read "oil" on it?? Didn't start it after I realize I put the oil in the wrong hole, I drained it.
It will usually just blow the oil out.
GFM
There are some interesting vids on that coming.
GFM
What do you think of the robinair vacuum, as I keep hearing it is a piece of yunk
I had a strange thing happen where I pulled a vacuum, turned the pump off and then oil started bubbling back out the vacuum line attached to the pump. Looked online and found likely culprit as check valve. Does this sound right and how do you get to the check valve to replace it? This could be a video in itself.
I have not seen a check valve in a vacuum pump. I will have to look.
GFM
Smart man 👍
The main problem with inches of mercury is that they are usually quoted as a relative scale compared to atmospheric, hence the max attainable number is always the same as your current uncorrected barometric pressure.
In my case the current uncorrected barometric pressure is 28.7" of mercury since I am at ~1000 feet elevation, if a manifold gauge set here reads a vacuum number higher than that 28.7", it is wrong plain and simple.
There is a review online of a guy who bought a vacuum pump and returned the 1st one because its windings were grounded, then returned the replacement because it wouldn't pull below 26", but he lives in Arizona where the mean elevation is 4000' AMSL so 26" could very well be the max attainable vacuum where he is.
Microns of mercury are quoted as absolute, 0 is a perfect vacuum no matter where you are.
Daniel Armstrong Good thoughts. I had not thought of it that way.
GFM
Love your videos watched all part 1-4. And I have a question. If you change an ac compressor, if I vacuum do I need to nitrogen purge too or the vacuuming takes care of all the nitrogen purging will do.
Kofi Ampofo Boadi If I am reading you right, you are asking if you need nitrogen in the system before evacuation. You do not. The nitrogen is for keeping the inside of the tubing clean while brazing and for leak testing. Hope this helps.
GFM
Thanks for responding.
I appreciate your response.
What is a good vacuum pump that I can buy that is not too costly? I am just starting to buy tools for service. Can you give me a good brand please.
I don't recommend brands, but the Robinaire on the video will pull a proper vacuum. Try Amazon
GFM
Welcome
GFM
Would you make a video disassembling a vacuum pump just for maintaining the Rotary Vane? Somebody told me, after several hours of use (100 Hours), you have to clean Rotary Vane and surroundings spaces and walls inside.
If you help us with this video, we would really appreciate it.
Thanks in advance.
+Francisco M. Del Castillo S. I will do that in the future, but if you change the oil with every evacuation there should be no maintenance that involves dissembling the pump.
GFM
What happened is, that I forgot to change oil every single use; so, I need to deeply clean the rotary vain and walls, so it will work as a brand new pump. But I'll wait til you made that video for all of us. Thanks a lot.
Sincerely
FDC
Hi GFM! I appreciate your work. It helps a lot! I have a question for you about my system at home. We occasionally hear a popping noise (similar to the sound of a bursting light bulb without the glass). This morning I noticed it happened right before the AC blower powered down. Also--the lights flicker when this happens. What should I check? Thanks!
Thanks! It is so random I doubt I will be able to capture it on video. If you heard it I don't think you would call it a "klunk."
do all pumps work with all types of major regrigerants?
Is it a problem if I put the oil in via the Exhaust/discharge oppening, not the oil rifill hole?
mirsad cviko Yes. It will probably blow out when the unit is started.GFM
I accidentally did this. Will it ruin the vacuum?
I'm gonna have to run a vacuum on my car a/c system after I replace the compressor is it ok to use the 5cfm 2 stage on it and if so about how long do I need to run it ?
Daniell Arvizo Its ok. I would pressure test it first with nitrogen for leaks. I would run it about 1/2 hr. Hope this helps.
GFM
grayfurnaceman OK thank you so much for the very informative video and advice.
thanks...
how long can you run a hvac pump for, 1 hour ? continuously ?? i want to use a hvac vacuum pump for bag pressing, cheers
Miles Dexter Tell me what exactly what you are trying to do.
GFM
grayfurnaceman it would be for forming gentle curved work with plywood veneers over a mould inside a vacuum bag
Please dear friend i want to purchaise this air vacuum pump 1/2. Hp. Manifold gauge digital in pakistan any of city thanks
These tools are available on Amazon, which is where I got them. Hope this helps.
GFM
On the way
GFM
It looks like the HF vacuum pump
So, as embarrassing and stupid as it is, I poured oil in the exhaust cap, I got confused because it says oil on it also, did I kill it?
I tested it out after, and it seemed to still work.
Thanks!
Bet you got soaked in oil when you fired it up. It won't hurt it.
GFM
grayfurnaceman haha. I actually caught on pretty quick, so I didn’t pour a ton of it in there.
Thanks for the reply!
I’m coming from an appliance background, slowly getting into HVAC, and your videos have been a tremendous help, but also part of my on going curriculum ! I appreciate that you take the time and enlighten us!
Thanks again!
How open should the exhaust cap be ?
One quick question, is air a non condensible?
gettin to it ent. Yes, anything that will not condense within the normal pressures that the system is normally under is considered a non-condensible. Air is made up of mostly oxygen and nitrogen which are condensible but only under extremely high pressures that most of these systems are not capable of. Hope this helps.
GFM
can a vacuum test hide a leak? if yes, how does it happen?
Yes it can. I have no idea why, but it can.
GFM
john joe It can suck a blown leaking seal back in place and seal the leak while in vacuum if that makes sense.
29.92 inches Hg, bro...
nice video though
i got to 30 use a fridge compressor there 10 fold stronger