The nitrogen tank (size D) should be replaced when the high pressure gauge reads 100 psi or less. To replace nitrogen tank disconnect the water chamber and turn off the nitrogen tank valve with the nitrogen wrench. Then set pump on its end with the nitrogen tank valve pointing down. Loosen band screw around tank and loosen chrome yoke "T" handle to free the tank. Remove tank and replace with a full tank. The new tank will have a new plastic seal attached to the medical post. Do not use it unless the old seal, which will be in the medical yoke is damaged. Never use two seals. Only nitrogen (N2) should be used. Position the tank's medical post into yoke so the two pins and the inlet in the yoke fit into the holes in the medical post. Tighten chrome "T" handle very tight. Tighten band clamp only slightly. Set pump down on it's feet and open nitrogen tank valve with nitrogen wrench slowly. The high pressure gauge (0 to 3000psi) should read 1800 to 1900psi. Adjust the low pressure (0 to 30psi)to 15psi with the brass "T" handle on the top of the regulator, which is on the top right side of the cabinet. Now turn off the nitrogen tank with the nitrogen wrench and turn the brass "T" handle counter clockwise and remove it from the regulator. Note on paper the high pressure (typically 1800 to 1900psi) and also note on paper the low pressure (typically 12 to 15psi). Check the high and low pressure in 12 to 24 hours. The high pressure should have not dropped more than 200psi and the low pressure should not have dropped more than 2psi. Now that you have established that you have leak free system you may open the nitrogen tank valve all the way counter clockwise and leave it open until the high pressure gauge reads 100psi or less, typically 3 to 6 months.

If the pump does not pass the pressure-leak test you must find where it is leaking. To assist you in locating the leak mix water and liquid dishwashing detergent (10 to 1) in a small plastic squeeze bottle. If the leak is a high-pressure leak apply water-detergent to the connection between the medical yoke and medical post, to all high-pressure threaded fittings, including the high pressure gauge. If on the other hand the leak is on the low the side, apply water-detergent to alllow-pressure threaded fittings. A large leak will show up as big soap bubbles, a very slow leak will look like foam or shaving cream. All leak tests should be done with the water chamber out of the system.

If your pump tests okay, but your nitrogen consumption is high your leak maybe in the water chamber. To test this empty the water chamber and replace the lid. Now connect the nitrogen line (top line) to the water chamber: Apply 15psi of nitrogen to the water chamber, while it is completely submersed in water. Note any bubbles that would indicate a leak.