Just Better Keeping the life of your pump User Manual

Tech tips from the pros

Keeping the Life in Your Pump

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IMPORTANT JB PUMPS ARE NOT TO BE USED ON AMMONIA OR LITHIUM BROMIDE (salt water) SYSTEMS. Pump maintenance is the responsibility of the owner.

Remember to change the oil. JB recommends changing oil after every evacuation and for larger jobs, you may need to change the oil a few times. Hydroﬂ ouric and hydrochloric acids and moisture collect in the oil. Left sitting in a pump, they act as an abrasive on internal surfaces, rusting and corroding them.

Figure 1

Cleaning and Testing Your Vacuum Pump

One of the easiest ways to spot if your pump is in need of a good cleaning is to look at the sight glass. If the oil looks milky, rusty, or full of debris, then the inside of the pump is in worse shape (Figure 1).

To clean, start the vacuum pump and allow it to run for about 15 minutes to warm up the oil. Make sure that you have allowed enough working room to safely drain and capture the oil. After the oil has stopped dripping, tilt the pump forward to remove any remaining excess oil (Figure 2). Then, stand the pump on the nose of the cover (Figure 3) to allow any trapped oil in the wells and stators to drain. Let sit for a few minutes and return the pump to its normal running position. Repeat tilting forward. Close drain valve. Dispose of contaminated oil properly.

Once the oil has been completely removed, return the pump to the position in ﬁ gure 3 and remove either the 2 rubber feet from the bottom of the pump or remove pump base (depends on the age of the pump which option is available). Next, turn the pump on to the motor end (Figure

4) and remove the 6 socket head cover screws holding the cover in place (Figure 5). Remove the cover from the pump and wipe the inside surface with a dry, clean rag. The sight glass is more difﬁ cult to clean. Try pouring in some solvent and using a pipe cleaner.

Figure 2Figure 3Figure 4Figure 5

Next, remove the oil deﬂ ector which is held in place with a socket head screw (Figure 6). Wipe with a clean, dry rag. If needed, a wire brush can be used to clean any discoloration to metal parts (this will not affect the pump’s performance once the cleaning is complete). Remove the cover seal and clean cover seal (Figure 7). Wipe the outside of the cartridge’s surfaces with a clean, dry rag. A wire brush can be used on all surfaces including the exhaust valve and the intake relief valve. If they are discolored, they will still perform ﬁ ne.

DO NOT DISTURB THE FOUR CARTRIDGE BOLTS OR THE TWO SMALLER HEX HEAD SCREWS (FIGURE 8). These are the

setting screws.

If the intake relief valve set or the exhaust valve set is damaged and needs replacing, these items can be ordered through your local wholesaler under JB Part Number PR-18. It is best to replace after completing the cleaning of the cartridge. Pay attention to the order in which they are assembled for correct reinstallation.

Reassemble the oil deﬂ ector (Figure 6). Clean out the channel for the cover seal with a clean, dry rag and smear some grease into the channel. This will help hold the cover seal in place for reinstallation of the cover. If the cover seal seems a little tight, stretch the seal a little and try again. All seals in JB pumps are designed to be reused. Reset the cover in place and replace the cover screws. Tighten in a crisscross pattern. Reattach feet or base.

Next, return the pump to its normal running position and place where you drained the oil. Open the drain valve, the 3/8” port on the intake, and the isolation valve. Have 1/3 cup of clean oil ready. Start the pump and pour the clean oil into the intake port. Let the pump run for 5 to 6 seconds and then shut the pump off. Drain the oil, tipping the pump forward as in Figure 2 to completely drain. Close the drain valve and dispose of spent oil properly after the ﬂ ushing is complete.

Figure 6

Figure 7

Figure 8

DO NOT

DISTURB THESE

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Cleaning and Testing Your Vacuum Pump Continued

Using Charging and Testing Hoses for Evacuation

DIRECTION OF PERMEATION

THROUGH HOSE WALL

Now, ﬁ ll the pump to the proper oil level and allow the pump to run with the isolation valve closed for 3 or 4 minutes to warm up the oil. Check all o-ring caps for dirt and proper seal. Connect a micron gauge (JB recommends the JB DV-22N pictured to the right) directly to either the 1/4” port or

Figure 9

the 3/8” port on the intake tee (Figure

9). Do not use a charging line. Open the isolation valve.

Using a charging line, especially a new line, will give you a higher micron reading because you are reading the environment inside the hose (see Figure 10).

Figures 9 and 10 are the same, but

Figure 10

ﬁ gure 9 is a direct connection hook-up and ﬁ gure 10 is a connection through a new charging line. Both hook-ups are

allowed to run the same length of time, but #9 is at 20 microns while #10 is at

297. If left on, the charging line hook-up will come down in its micron reading, but it will take a much greater period of time. If the hose is cleaned out with alcohol and vacuumed for a long period of time, the micron reading will go lower.

This test can be performed on a pump with dirty, used oil and then with the pump cleaned and ﬂ ushed, as described earlier, to see the difference that just maintaining the cleanliness inside your pump affects the performance for deep vacuum.

Isolation Valve

It is a quarter turn between on and off. There is no additional valve needed to isolate the system. When checking for pressure rise, slowly turn the handle counter-clockwise. The pause position is at 45 degrees and the valve is completely closed at 90 degrees (Figure 11).

PAUSE POSITION

CLOSED POSITION

Figure 11

OPEN POSITION

You probably think there is a leak. However, an evacuation/ dehydration hook-up requires a leak-proof design in all of the components. Only soft copper tubing, pure rubber hoses, or ﬂ exible metal hoses are absolutely vacuum tight. Charging hoses are designed for positive pressure.

CHARGING SYSTEM

Gas under pressure in the hose

will permeate to the lower

pressure of the atmosphere.

Even with the advanced technology of today’s hoses, permeation through the hose compound still exists (Figure 12).

If you have blanked-off your pump to check pressure rise and your hoses and connections are not leak-free, the atmosphere will permeate to the lower pressure in the hoses. Your reading will slowly rise and you will spend time look-

EVACUATION (Hose under Vacuum)

The atmosphere which has a higher

pressure permeates to the lower

pressure in the hose.

Figure 12

ing for system leaks.

Information on Testing the Vacuum Pump’s Isolation Valve

The easiest way to test the isolation valve for leakage is to turn the pump on with the isolation valve in the closed position. Connect a charging line to the center port of the manifold (Figure 13), and have the high side capped off and CLOSED and the low side capped off and OPENED. Then, connect the charging line to the intake of the pump and wait. If, within 5 to 10 minutes, you do not see the low (compound) gauge going into inches of vacuum, there is no leak in the isolation valve.

What does happen when a micron gauge is connected directly to the intake of a vacuum pump with an isolation valve/ It is all related to the connections to, and including, the intake, the volume of what is being vacuumed, the depth of vacuum, and the length of time that the volume is in the deep vacuum.

Figure 13

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