Just Better Deep Vacuum Principles and Applications User Manual

Page 4

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Dispelling The Argument Of

“No Deep Vac On Heat Pumps, Etc.”

The word “sublimation,” the ability of moisture

to go directly from solid ice to vapor without

passing through a liquid state, is commonly used in

vacuum. This phenomenon is observed when the

wash is hung out in the winter and freezes solid.

Still, in time it dries due to sublimation (drying). If

lines are in a cold ambient, it is possible to have

ice in the system. It will be removed during

evacuation. Of course, the addition of heat (heat

gun only) at these cold spots speeds up the job.



500 Microns

Evacuation Complete

Slow Rise To

1500 Microns


Rapid Rise To ATM


Pressure Rise Test

We previously mentioned that the only difference

between deep vacuum and the methods of the past is

that we can measure what we have done. This is called

the Pressure Rise Test.

When the sensor reads between 300 and 400


DV-29 Method. Blank-off the high and low side ball

valves attached to the system.

General Hookup Method. This includes using

copper tubing or metal hose to the high and low side.

Close blank-off valve on the pump. This will isolate the

gauge from the pump.

Wait for at least 5 to a maximum of 20 minutes to

allow system pressure to equalize. The reading you see

at the end of this test will be very close to what you

actually have in the system. A rapid rise during this test

to atmospheric pressure indicates a leak, while a slower

rise to around 1500 microns indicates moisture is


Printed in U.S.A.

2007 JB Industries Inc.

Evacuation Brings Out The Worst In A System!

vacuum, oil must be clean and mois-

ture free throughout evacuation. Just

take a few minutes during and after

each job to drain, flush and refill. Keep

your pump running at peak perfor-

mance and maintenance free for years

to come.

Always store your vacuum equip-

ment plugged or capped to prevent

contamination due to condensation

and dirt. Because a slight cut or dirt on

the o-ring seals can cause leaks, the

mating flare fitting faces should be

wiped and checked for damage before

hookup. Vacuum pump oil makes a

fine lubricant at these connections.

After closing

the isolation

valve, open

the gas

ballast valve

and shut the

pump off.

There are many evacuation level recommendations

including the statement “evacuate the system to below

200 microns.” This should not be considered. Note we

say “system” because it is possible to evacuate piping or

some component other than the compressor to below

this level. Refrigeration oil has a vapor pressure and by

going below 200 microns, you will degas particles of the

refrigeration oil. By changing the makeup of the oil, it will

no longer be a true lubricating oil.

Remember, hydrofluoric and hydrochloric acids, and their

pal, moisture, do collect in the oil. Having nothing but time

on their hands, they effectively destroy pull down and act

as an abrasive on internal surfaces. If left sitting in an idle

pump, these culprits keep busy by rusting and corroding

internal surfaces. Deep vacuum pumps need a fill or two

for every job.

In order for your pump to pull a near perfect

JB Industries

PO Box 1180

Aurora, IL 60507-1180


e-mail: [email protected]

Technical Assistance