HVAC Vacuum Pump Maintenance

[phuckq]

I've had problems with those yellow jacket pumps with the built in gauge on the pump itself sticking. I now use a JB and have so far had no problems.

[Cema23]

oh, okay :-) thanks for the response

[fyp777]

Hi DrZ

like your video.

when is the gas ballast on vacuum pump should be open or close.

thank you

[usernamekjah]

Hey Q-Q (quick-question) do you still own/use that same vacuum pump?

Has any problems came up with I know if the brand but some folks say its heck if the van goes on it since there aren't replacement parts for it. And the options are buying a pricey pump cartridge or just a new pump....Sorry Q-Q and long question. Hahaha

[DrZarkloff]

@usernamekjah I'm very happy with this vacuum pump.

[Cema23]

Oh :) now i know. ty

[OneBiOzZ]

how often should you change the oil?

[DrZarkloff]

@OneBiOzZ Some techs replace the oil after each use.

[BGreenHVAC]

@OneBiOzZ By EPA guidelines (per section 608 refrigerant handling license) you are supposed to change the oil after every use. You should drain the oil only when the pump is warm/hot. It will take more contaminants like moisture with it. Since the oil is very hygroscopic, you should not refill the oil until you are ready to use the pump. Also, use the smaller oil containers. From the moment you break the seal the oil is absorbing water vapor from the ambient air. The oil is deteriorating

[BGreenHVAC]

@OneBiOzZ Remember that is the "textbook" answer. Not many techs follow this. If you are unable to reach a deep vacuum, the contaminated oil could be a factor. I have seen a coworker unable to get a deep vacuum and searched for hours for a leak. He called me to take over the job while he went to another one. I changed the oil, and I achieved a vacuum of 326 microns. I didn't leak, he just overlooked the obvious because he didn't just stop to think about it. His oil was milky (the answer).

[Cema23]

can this be used in balloon castle?

[DrZarkloff]

@Cema23 If you can figure out how.

[DragonFlyback256]

@Cema23

LOL, i think not. It could make the pressure if you give it time and the balloon castle is completely leak free. Vacuum pumps compressors usually have not much flow volume so it may take a looong time.

[ashlianne]

DrZ it's possible to use a compressor as a vacuum pump?

[DrZarkloff]

@ashlianne I suppose that it's fundamentally possible. Vacuum pumps are inexpensive. You're really better off just buy one.

[DrZarkloff]

@morbius0987654321 True. I was just showing the basics.

[coltonnaslund]

I need a video to hook up a vacuum pump and vacuum gauge properly please!

[DrZarkloff]

@coltonnaslund Please check out my video entitled, "HVAC Triple Evacuation".

[BGreenHVAC]

@coltonnaslund If you do not understand how to do this basic task, how are you able to get refrigerant? In my area you are required to have an EPA License to handle refrigerants, and a mechanical license to perform any work on units. If you don't understand the basics, you shouldn't be doing it. this task is in every textbook I ever seen in HVAC school. It is also in the parts catalog as well as the packaging of the vacuum gauge, and in the instructions of the vacuum pump.

[BGreenHVAC]

PLEASE, tell me you are not working with refrigerants! An undercharged or overcharged unit undergoes excessive wear and tear in addition to being inefficient on utilities. If you don't know what you are doing. Learn before you work on systems. I hate it when somebody who is uneducated cuts corners and makes the customer feel like they got a good deal, but in reality they were screwed. The job was not done right. I encounter this often. Watch Dr. Z's Hacked video. I get a laugh

[death2opposeme]

... well, did about six or so oil changes on the vac pump trying to get all the watery oil out, forgot what additive i was using in addition to fresh oil. but the vac pump he had been using for years just was crapped out after that. got a new 9cfm jb though :D

[DrZarkloff]

@death2opposeme I'd like to recommend using Emerson liquid line filter driers for the best moisture removal. It sounds like you'll have to replace the drier a lot after installation.

[death2opposeme]

we had that same pump... it got waterlogged. um chiller unit had bad compressors, why, chiller(radiator looking thing) busted, why? some dumbass put flow control on backwards and wired wrong. so the day i tried to recover refrigerant i was recovering water!!! and i used the vac pump on the rec unit and gauges.

[ZuffaLtdDanaWhite]

Dr. Z, is it any different when and if you were to change the oil while its hot...then empty... then fill with fresh? or just the way you did it is fine? My boss has this poster up at work for vacuum pump maintenance; oil changing and it suggests always letting it run for a good 10-15mins before changing oil. Whats your word on this?

[talisman227]

There is also nothing wrong with running your vacuum pump for about 15 mins before draining the old oil. This will heat up and "loosen" the existing old oil as well as bring any debris back into suspension so it will come out with the hot oil when drained rather than having some still settled at the bottom after a "cold" draining.

[hpaddyh]

on absortion chiller along with nitrogen break because of deep vacuum required.

You should always verify tightness of system if nothing else but to insure system leak free, you know double check your work.

[hpaddyh]

of tightness of system. usually small ac systems don't have big problem with moisture simply because of high evaporator temps. good practice to change dryer, if able change oil and do a double or triple nitrogen break. Of course this is under extreme moisture problems but should always at least do the micron test. industrial chillers like absorption and centrifugal chillers you have to do all.

Ex. I have worked all nightb changing vacuum pump oil-cont.

[hpaddyh]

keeping oil clean in vacuum pump not only good for life of pump but also allows for deeper vacuums from pump. It's also good practice to change oil periodically if you have to pull deep vacuum. Also breaking vacuum with nitrogen and restarting vacuum again will dry system out. valving off system when you reach 300-500 microns and waiting 15 minutes or so to see if there is no more than say 500 micron rise will give you very good indication, cont.

[nathanrhodge]

I believe the EPA only requires you to pull a vacuum of 500 microns and does not require it to stay below 500. I personally pull new systems down to a least 300 after leak testing with nitrogen. If I think the line-set was exposed to water, I'll just leave it running all day or even all night. No sense in charging a customer to sit around watching a vac.

[prolodyne]

Some systems that have to be vac'd out (I'm not talking necessarily HVAC) have heater elements to warm up pipework, pressure vessels, etc. to help dry out the system faster when pumping down...

[DrZarkloff]

Good thinking.

[tiagobaracho]

but i read that after i achive the 500 micons i should still left the vacuum pump por 15 - 20 minutes on . Why is that ?

Thanks

[DrZarkloff]

I don't know why you'd have to keep the vacuum pump running for an additional 15 minutes. However, it is a good idea to keep the system under deep vacuum for about 15 minutes to be sure that you don't have any leaks.

[tiagobaracho]

Actually i just made a test and discovered WHY this is needed.

The reason is because even when you get vaccum, may be still water on the system, so you need to keep it in vaccum to the rest of the water evaporate and the moisture will be released by the pump. This is the reason why it should be on for a while even after it get to vaccum.

Thanks

[ale24541]

You need to keep the vaccum pump running at least a half hour by two reasons:

1: At -30"Hg the water boils at 20ºC (68ºF), so when you do vaccum the humidity becomes a gas (steam). Because there isn't pressure in the circuit (there isn't air in it) the gas particles rebounds along the circuit and takes more time to get it out.

2: The compressors have oil wich captures micro bubbles of air. When you do vaccum, the bubbles have to rise trough the oil until they reach the surface.

Do this test:

[tiagobaracho]

Man.. thanks a lot... nice answer !

[doyengicp]

oil sealed rotary pumps dont go down to molecular flow.. they always work on viscous flow. so there's no molecule bouncing around ;)

the delay to go to base pressure is almost entirely due to water outgassing. even on high vacuum or ultra high vacuum systems it can take hours, or days to reach a good pressure depending on the application.

The gauges used on that kind of pumps are usually not very accurate. a fully pumped chamber and an outgassing chamber may show almost the same indication.

[Shujiro8855]

@doyengicp hi, oil sealed pumps do pump past transition - molecular flow, well around 40 millitor on some roughing pumps , which is just into mollecular flow.

[doyengicp]

@Shujiro8855

Molecular flow is way past 40 mTorr ;) thats not a great level of vacuum actually.. even dry pumps with roots blower cant reach it.. there's always gas backstream.

[ale24541]

...fill a bottle with oil, put the cap and shake it (you will see a lot of bubbles). Apply vaccum and look at the bubbles. They will go to the surface of the oil level. Measure the time the bubbles need to travel from the bottom to the top, consider some billon of bubbles and you will see that this process takes a lot of time!

I allways do vaccum for more than 45 minutes to be sure the humidity is off.

[pclle]

if you are at 500 microns and it stays at 500 if you isolate the system from the pump you should be fine, the reason for letting it run is a little bit of an insurance poilicy that you should be boiling off and residual moisture hidden in the system.

[lexichronicle2]

@tiagobaracho it'd be an idea to leave the pump on to make sure all the water has boiled off in the system. i have never fixed HVAC (we don't rly have it in the UK, not as much as you guys, since it's balls cold here most of the time), but I have done a fair amount of chemistry involving boiling things under vacuum. if you pump down then immediately disconnect, you may not have given it long enough to all boil off. nice pump, i wanted one of those since I was 11. now I have an edwards :P

[lexichronicle2]

@tiagobaracho search for a video called "Water to ice in 90". it's from edwardsvacuum, who make lab pumps. the pump in that video pulls a hard vacuum and it has a high CFM, but look at the water... not a whole lot of it goes anywhere, especially once it's cooled it's self by evaporating. another reason to let the pipes warm up, or purposefully warm them, and give it time to drag all the moisture off. go for a smoke / coffee in the meantime :)

[tiagobaracho]

Hi Dr.Z.... me again !

Look.. there´s something i never understood well. I always hear about set up the vacuum pum and leve it for 15 minutes or more on a Split system, for example. But if you look at the vacuum gauge in 20 - 30 seconds you already get as low vacuum as possible , after that it just runs and nothing change. Whats the explanation for leaving a vacuum pump so long on if the system get to a vacuum state very earlier. Thanks

Greetings from Brazil

[DrZarkloff]

You should evacuate the system to 500 microns. It doesn't matter how long or how short of time it takes.

[hackfreehvac]

Changing the vaccum pump oil is easily neglected by many of us, just like changing the oil on our cars. But just like changing the oil on our cars, it is important in the life of the equipment.

[DrZarkloff]

Very true.

[leeanator]

oh dear

[itscool1968]

actualy it looks a little on the high side according to the fill lines on the case or was the pump slightly tilted?

[DrZarkloff]

It went a little over the line but it will be okay. Thanks

[itscool1968]

sorry jim just had to bust on ya a little to keep you on your toes :)

hows the lawn mowing and wife videos comeing:)

[DrZarkloff]

I'm working on the script and a friend of mine will be helping me with it. I hope to have something in a week or so.

[mechanicwarrior20]

yay...

good video

[DrZarkloff]

Thanks

[jimmymoss7644]

i change my pump oil very often. the company pays for the oil anyways. good vid sir.

[DrZarkloff]

Thanks. I usually change the oil after each job.

[jimmymoss7644]

ya same here.