Tech tips from the pros Keeping the Life in Your Pump Copyright© 2009, JB Industries Inc.
3 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. Hydroflouric 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 IMPORTANT JB PUMPS ARE NOT TO BE USED ON AMMONIA OR LITHIUM BROMIDE (salt water) SYSTEMS. Pump maintenance is the responsibility of the owner.
4 Cleaning and Testing Your Vacuum Pump Continued Now, fill 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 the 3/8” port on the intake tee (Figure 9). Do not use a charging line. Open the isolation valve.
6 Information on Testing Vacuum Continued Brass isolation ball Adapter nut w/ o-ring Stem w/ o-ring Teflon seals (2 each) Retainer ring Retainer Plug w/ o-ring Poly Ball 7/16” (oil check system) Figure 14 First, let’s look at the construction of JB’s isolation valve (Figure 14). This figure shows the isolation valve in the closed position. The brass ball is sandwiched between two Teflon seals, making a positive seal, with a solid brass surface blocking access to the intake chamber.
8 Information on Testing Vacuum Continued 9 stretches back as far as when Inches of Mercury (inHg) was the way measuring of a vacuum on a system was taught. A charging line hose can be vacuumed to 50 microns if it is clean. New environmental hoses, fresh off of the shelf, will only reach about 300 microns until they are cleaned out with alcohol and vacuumed out for a while. Why is this? First, the charging lines are mostly gaskets made for positive pressure. Second, they are permeated.
10 Information on Digital Micron Gauges 11 Information on Digital Micron Gauges Continued There are three main complaints that are stated on the returns that JB receives from the DV-22N and DV-24N. First, “inaccurate readings”. Second, “erratic readings”. Third, “will not hold a vacuum”. Each of these complaints involves both the understanding of the gauge functions and the principles of vacuum.
12 Information on Digital Micron Gauges Continued As the system is being evacuated and the micron level is dropping down through the increments of the gauge’s display, the gauge will re-sample ambient temperature about every 60 seconds. When this function is taking place, the gauge’s display will show “auto-cal” (older gauges may see that the display freeze prior to the re-sampling). The re-sampling lasts for about 15 seconds after which the micron level that the system is at will then be displayed.
14 Replacing Coupler (Motor Removed) 15 Troubleshooting: Pump Hard to Start Coat setscrew threads with removable thread sealant. Align coupler setscrew with flat surface of cartridge shaft. Tighten screw so coupler slides on to shaft but stops at the bottom of the flat. Tighten until screw head is flush with coupler surface (approx. 40 in. lbs.). 1/8" Bottom Of Flat Correct Incorrect Sight Glass Repair Step 1: With cover off of the pump, lay on two blocks of wood.
Cross reference of Vacuum Measurements Boiling Temperatures of Water at Converted Pressures Temp. F° 212 205 194 176 158 140 122 104 86 80 76 72 69 64 59 53 45 32 21 6 -24 -35 -60 -70 -90 Microns 759,968 535,000 525,526 355,092 233,680 149,352 92,456 55,118 31,750 25,400 22,860 20,320 17,780 15,240 12,700 10,160 7,620 4,572 2,540 1,270 254 127 25.4 12.7 2.5 0.00 JB Industries Technical Support 800-323-0811 www.jbind.com Inches of Hg Vacuum 0.00 4.92 9.23 15.94 20.72 24.04 26.28 27.75 28.67 28.92 29.
