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BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22314
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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Can a person use an a/c vacuum pump to recover refrigerant

Customer Question

Can a person use an a/c vacuum pump to recover refrigerant from a system - how would you connect the storage bottle? How to determine what the better a/c refrigerant recovery unit to purchase for home and automotive use?
Submitted: 5 months ago.
Category: HVAC
Expert:  Webb-Guy replied 5 months ago.

Hello and welcome to just answer my name is ***** ***** I will be the one who will assist you. Do you have a recovery pump?

Customer: replied 5 months ago.

No was thinking about getting one. I do have a vacuum pump. But would definitely like to be able to use the vacuum pump if possible.

Customer: replied 5 months ago.

What about a new unit?

Expert:  Webb-Guy replied 5 months ago.

I personally have never used a vacuum to do this its always been a recovery pump so I will open this up for you and see if someone who has done it can further assist you.

Customer: replied 5 months ago.

Ok... how to determine what the best a/c refridgerant recovery unit to purchase for home and auto use.

Expert:  BillyHvac replied 5 months ago.

Hello,

my name is Billy. 25+ years of using recovery machines and vacuum pumps.

The vacuum pump is only made to create a vacuum, not transfer refrigerant.

To actually remove refrigerant you need a recovery machine.

If you tell me what type of jobs you do and how often I can tell you what you should be looking at.

Customer: replied 5 months ago.

Auto 134 and sometimes R22, R421A and such.

Expert:  BillyHvac replied 5 months ago.

ok so no large projects involving 20 lbs or more at a time?

Customer: replied 5 months ago.
No
Expert:  BillyHvac replied 5 months ago.

Then you would like something smaller like the Robinaire RG3000. Around $450 but compact and does a good job.

For larger scale I would look at Appion

Customer: replied 5 months ago.
Do you know about a " JB INDUSTRIES F5"?
Customer: replied 5 months ago.
What about using the heat pump compressor (unit) to discharge the refrigerant into a container with a vacuum?
Expert:  BillyHvac replied 5 months ago.

I am familiar with the f6...let me check specs for an f5

Expert:  BillyHvac replied 5 months ago.

What about using the heat pump compressor (unit) to discharge the refrigerant into a container with a vacuum?

This also not possible.

Do you just have a unit you are trying to get empty for a replacement?

Customer: replied 5 months ago.
No one I was thinking I could recover and reuse refrigerant. I am working on my house trane heat pump.
Expert:  BillyHvac replied 5 months ago.

I cannot find pertinent info on a F5..only the F6.

You can recover the refrigerant and reuse.

Is your project inside the outdoor unit or in the line set or indoor unit?

Customer: replied 5 months ago.
Sorry it is F6. It is outdoor heat pump
Expert:  BillyHvac replied 5 months ago.

if you are not actually in the heat pump..replacing compressor, reverse valve....you can push the refrigerant into the coil, shut vales and lock the refrigerant in the outdoor unit and then unhook lines...but if the outdoor unit itself is being opened up you need a recovery machine...AND a vacuum pump for when ready.

The F6 would be very acceptable....a little more machine than you need for light use.

Customer: replied 5 months ago.
Here is what the gauges read after vacuuming and putting 5.6 lbs of 421-A into the unit. The heat pump had rubbed a hole in the 1/2" line so I cut it out and put a coupling to fix. Afterwards I put nitrogen into it to test for leaks - nothing. Then I charged system (was told no more than 90 percent of 421A fluid in an r22 unit). But after charing (using a digital scale so I would no go over) the system was not cooling.
Customer: replied 5 months ago.
I know this question has been much more - Will give a bonus. Any and all help in guiding me to solve this wii be appreciated. Thank you your customer
Expert:  BillyHvac replied 5 months ago.

ok first, did you vacuum the system when done?

Also you appear undercharged. What is the temp outside and inside when you took those readings

Expert:  BillyHvac replied 5 months ago.

and are those readings while running?

Customer: replied 5 months ago.
First correction ment will
Customer: replied 5 months ago.
Unit was running and temperature was around 87 or so.
Expert:  BillyHvac replied 5 months ago.

when you charged the unit...did you charge mostly with liquid?

Customer: replied 5 months ago.
I put an hour or so vacuum
Customer: replied 5 months ago.
the bottle was upside down on the scale.
Expert:  BillyHvac replied 5 months ago.

Are you at the site right now?

Expert:  BillyHvac replied 5 months ago.

I would like you to charge the unit until the red gauge is closer to 255-260.

Once at that point tell me what the blue side gage is at.

Customer: replied 5 months ago.
Ok... I will need 30 minutes or so to get setup.
Expert:  BillyHvac replied 5 months ago.

no problem just reply when ready.

The 90% is to start watching it at that point as it depends on metering device for final op.

You may have to go 100% or a bit more...

Customer: replied 5 months ago.
Here is the gauges to work with. The others were not mine.
Expert:  BillyHvac replied 5 months ago.

any refrigerant gages as long as the red goes to smaller 3/8's line and the blue to the larger with black rubber on it

Customer: replied 5 months ago.
Expert:  BillyHvac replied 5 months ago.

Those gages will still work great

Customer: replied 5 months ago.
What lines go where?
Expert:  BillyHvac replied 5 months ago.
Customer: replied 5 months ago.
Gauges are off
Customer: replied 5 months ago.
Expert:  BillyHvac replied 5 months ago.

correct....start unit and tell me pressures

Customer: replied 5 months ago.
Unit on
Customer: replied 5 months ago.
Unit still on
Customer: replied 5 months ago.
It is 91 degrees here
Expert:  BillyHvac replied 5 months ago.

i cannot make out the blue gage...what is psi reading?...id the larger line with black rubber cool or sweating yet?

Expert:  BillyHvac replied 5 months ago.

and at 91 degrees lets charge to red gage to 265 now.

Customer: replied 5 months ago.
No not sweating yet or that cool
Expert:  BillyHvac replied 5 months ago.

is the indoor blower running ok, Clean filter? doors on the blower unit inside? good air flow from register?

Or was there any frost/ice on the black rubber line at the indoor unit?

Customer: replied 5 months ago.
Indoor blower - inside the hour on the ceiling filers?
Customer: replied 5 months ago.
The indoor filters are new
Expert:  BillyHvac replied 5 months ago.

and blower is running good with good air flow out the registers?

Customer: replied 5 months ago.
Doors on the blower unit inside?
Customer: replied 5 months ago.
there is a slight bit of cool air from ceiling vents. Let me get the laser gauge to it.
Expert:  BillyHvac replied 5 months ago.

You have a blower inside correct? I want to make sure all air flow is going through coil and doors are on the indoor unit and not off the unit...basically I am asking if the indoor blower is all together.

And did we charge it to 265 yet

Expert:  BillyHvac replied 5 months ago.

can you post a pic of the indoor unit?

Customer: replied 5 months ago.
85.7 from ceiling register
Expert:  BillyHvac replied 5 months ago.

are we at 265psi on red gage yet?

Customer: replied 5 months ago.
I have a unit in the attic and a heat pump outside. No I have not filled it up. The yellow line on the gauges fitting is larger that the male fitting on the bottle.
Expert:  BillyHvac replied 5 months ago.

thats because you have automotive gages...I thought you had an adapter or had used those gages. You need r22 gages..the ones you have are for 404, 134 etc..

Expert:  BillyHvac replied 5 months ago.

I have to go offline for 30 min but will respond as soon as I can. At this point we still need to raise the pressure a bit.

Customer: replied 5 months ago.
Customer: replied 5 months ago.
Customer: replied 5 months ago.
Ok... I will make my way to Harbor freight to get an adapter
Customer: replied 5 months ago.
Still not sweating on large line. What direction is the heat pump fan supposed to turn?
Customer: replied 5 months ago.
Unit off
Expert:  BillyHvac replied 5 months ago.

when the fan turns the lower edge should be leading. The air should be blown upward out of unit

Customer: replied 5 months ago.
While I was gone I left the gauges connected. After turning on again here was the pressure. Now I noticed that the fan was going the wrong direction so I unplugged the two wires on top of the unit and flipped and reconnected them.
Expert:  BillyHvac replied 5 months ago.

ok so fan is correct now...and we still need to get the head pressure to 265ish

Customer: replied 5 months ago.
The gauges where snugged and not leaking. No I had a section of the copper tubing on the 1/2" line (which had a pin hole in it from rubbing on the bottom metal base) removed and a section of tubing rebrazed.
Expert:  BillyHvac replied 5 months ago.

we still are undercharged

Customer: replied 5 months ago.
I was unable to locate the adapter to fill.
Expert:  BillyHvac replied 5 months ago.

Here is the summary thus far.

There is too little freon in the system right now...as it circulates through the indoor coil it is being used up quickly.

We need to increase the head pressure b adding refrigerant until we are at 265-270 with an outdoor temp of 90.

Customer: replied 5 months ago.
Ok... now what about leaving the yellow center hose on the gauges connected to itself and use the red hose - which it fits?
Customer: replied 5 months ago.
To the bottle
Customer: replied 5 months ago.
Can we connect one of the two (red or blue) hoses to the bottle and the other to the unit? Or is it better to wait till I get the other gauges or adapter?
Expert:  BillyHvac replied 5 months ago.

Take the blue hose...move to center in place of yellow.

Leave red attached to unit.

make sure blue knob is shut down....then meter in refrigerany by opening the tank valve and the red knob...turn off red knob when 265-270 and tell me if the black rubber line is getting cooler.

NOTE...this is not how I would normally instruct...I am just trying to help you get by

Customer: replied 5 months ago.
Had to move fitting over. Ok... now I can use the digital scale or not - which way? Also will the bottle be upside down or right side up? Plus... will I need the unit turned off while connecting the hoses but back on before I open the bottle?
Expert:  BillyHvac replied 5 months ago.

I am going to change something here and have you charge it while running.

Move RED hose to center..set yellow aside.

Attach blue hose from blue knob side of gage to to the larger pipe service fitting

Red hose is attached to tank of refrigerant and goes to center gage port.

open tank valve

red gage valve closed

Tank upside down

start unit

while running slowly open blue knob tell me if the blue side gage rises while charging

Only do this for about a minute.

Then swap hoses back to where you can take a pressure reading with red gage attached to skinny line

Customer: replied 5 months ago.
This is blue side pressure before charging or unit turned on. Still move forward? Everything is connected and ready to go.
Expert:  BillyHvac replied 5 months ago.

yes it is correct...once unit runs that pressure will drop

Customer: replied 5 months ago.
Well unfortunately I just created more problems. Even though they are tight they are now leaking. I will just have to wait to borrow my friends. It seems like there is other issues like the direction of the fan. Now why would it keep starting up in the wrong direction (even when I swopped the motor wires?
Customer: replied 5 months ago.
That is my gauges
Expert:  BillyHvac replied 5 months ago.

The refrigerant issues vs fan are not related.

It appears the fan motor may be defective but that is open to troubleshooting.

As far as the gages I guess we wait until we have working gages

Customer: replied 5 months ago.
Was able to correct the leak on the gauges. I filled it up with a lot of liquid refrigerant and here is the results.
Customer: replied 5 months ago.
Are you supposed to fill the whole unit liquid or gas?