Pump Seals and Orings

Pump Leaks. Far and away the most common source of leaks is bad orings in the pump head. Over 5 years, we have had only 4 pump seals replaced. Two of these were due to faulty seals during the manufacturing of the pump. The other two cases involved pumps that are not used for wine---rather a more aggressive product.

If you clean or replace an impeller, and then have a leak, it must be the result of a bad oring--or mispositioned oring.

Enoitalia Frequency Drive Pumps.

The pumps consist of 3 components. The Pump Head, the Motor, and a Middle Section connecting these two. There are two interfaces that must be water tight. It is important to carefully inspect the leak to be certain of its origin.

Leak 1. The first is the interface of the Pump Head---along the seam between the Pump Head and the Middle Section. This is easily fixed with new orings--or simply repositioning the orings.

Leak 2. From the Drain Hole in the Middle Section. The second interface is on the drive shaft of the motor. This requires changing the seals and is more tedious--although not difficult. It is rare to have leak due to the seals.

It is very easy to mistake the origin of the leak. Uses your finger to locate the Drain Hole on the underside of the Middle Section. If the seals are bad, you will have a leak here.

Figure 1. Pump Head removed

Figure 2. Stainless steel plate removed. There is one large oring and one small oring. Additionally, you can see the Snap Ring and shaft seal. Do not attempt to remove the shaft seal from this position.

Changing the Orings--This seal is made by 3 orings (2 large and one small).
1.)Remove the pump head--5 metric allen bolts. There is one large oring in a groove on the pump head. Please note that the other two orings are behind the stainless steel plate in this photo. Tip the pump with pump shaft pointing downwards, and gently tap on the stainless steel plate. It will drop off the shaft. See Figure 2.

If you do not need to replace the Seals (only the orings) then clean the pump head, lubricate the new orings, and reassemble. Use a little grease to help hold the orings in position during reassembly. Be sure to lubricate the impeller as well. Be sure to tighten the 5 allen bolts in a round robin fashion and DO NOT OVERTIGHTEN. Just snug them up. Restart the pump and check for leaks. If there is a drip, then gently tighten the allen bolts--the leak will stop with only modest torque on the allen bolts.

Changing the Pump Seals

There are slightly different procedures for the various pumps. This procedure is for the Freq Drive pumps of Enoitalia.

Figure 3. If you need to change seals, first remove the Snap Ring--this holds the seals in position.

Figure 4

You must separate the 3 components of the pump. You have already removed the pump head.

1. Remove the Snap Ring from the shaft. The Snap Ring retains the seal on the shaft. If you bend it during this step, you can squeeze it back into shape with pliers before reassembly.

Photo shows the two seals and snap ring.

You can get a Snap Ring Pliers at any hardware store of home improvement store.

Separating the Motor from Middle Section.

1. Remove the Motor from the baseplate.

2. Remove the fan cover at the back of the motor. 4 small screws.

3. Remove the 4 long bolts that extend from the back of the motor to the Middle Section.

4. Use screwdriver to pull outer pump seal off the shaft. Lubricate the shaft to make this easier.

4. Use a rubber mallet (or wood block) and tap the middle section to separate it from the motor. Do not pry with anything that will damage either the threaded holes on the Middle Section or the Motor. Pry the two apart carefully. Lubricate the motor shaft to make the separation a little easier.

Figure 5. Middle Section with Pump Seals. The inner seal is inside in the Middle Section. It is rubber and ceramic.

Figure 6.

1. Remove the old pump seals from the Middle Section. Clean the middle section and lubricate.

2. Place new Rubber/Ceramic Seal in Middle Section. Note the white ceramic is facing out. Use lubricant and press with your fingers to seat it. Do not strike it---avoid breaking the ceramic.

3. Clean (emery cloth is good) and lubricate the pump shaft. Place Middle Section on shaft. Gently tap with rubber mallet until the long bolts can reach their respective threaded holes on the Middle Section. Be sure the Drain Hole is at the bottom of the motor.

4. Tighten the 4 long bolts in a round robin fashion---this will pull the Middle Section in firmly against the motor. Do not overtighten.

5. Put outer seal on the motor shaft. Note the orientation of the outer seal. The spring of the outer seal must be on the outside--facing the pump head. Be sure the shaft is lubricated and push the outer seal on firmly until it reaches the inner ceramic seal.

6. Replace Snap Ring. You can bend the snap ring back into shape with pliers before doing this.

7. Use a piece of plastic pipe to push the snap ring into its groove. For the Euro-40, a 3/4" PVC pipe works well. Larger pipe is needed for the larger pumps.

 

Now replace the Pump Head. Clean the pump head, lubricate the orings, and reassemble. Use a little grease to help hold the orings in position during reassembly. Be sure to lubricate the impeller as well. Be sure to tighten the 5 allen bolts in a round robin fashion and DO NOT OVERTIGHTEN. Just snug them up. Restart the pump and check for leaks. If there is a drip, then gently tighten the allen bolts--the leak will stop with only modest torque on the allen bolts.