1. Where is the best location for a Sentinel Vacuum Controller?

For best performance, Sentinel Vacuum Controllers should be located:

  • as close to the milk trap, as possible, in a milking vacuum system or

  • as close to the system to be regulated in other types of applications.

2. When should I change the Top Dome Filter?

If removing the Top Dome Filter changes the vacuum more than 1/2 inch Hg, then the Top Dome Filter should be replaced.

3. Do I use the Filter Gauge and paper filter when I install a Sentinel Peacekeeper on either a Model 100, Model 350 or Model 500 Sentinel Vacuum Controller?

No.  When a Peacekeeper is installed on the above units, the Filter Gauge and paper filter (AP-58 or AP-107) are not used.

4.  Where can I purchase printer ribbons for my Digimet Printer?

The Digimet Printer uses an Epson HX-20 cartridge ribbon. Ask your STAPLES customer service representative for the following part number, EPS-H00CRBB.

5.  How can I make my vacuum system more efficient?

Several things can be done to make your vacuum system more efficient.  First, the vacuum controller should be properly and periodically maintained.  Second, the vacuum controller should be properly placed in the system.  If the controller is placed too far away from the milk trap or too far from the system which is to be regulated, then the controller may not respond properly to vacuum fluctuations.  Third, the vacuum pump should be the proper size for the system.

6.  How much quieter will a Peacekeeper make my Sentinel?

The Sentinel Peacekeeper will cut up to 15 decibels off your present noise level created by the Sentinel.

7.  Do I need to adjust the Sentinel Relief Valves?

Although the Sentinel Relief Valves (348-17 and RV-463) are set at the factory, they must be readjusted on the system that they are intended to be used on. This can simply be done by turning the inside screw-clockwise to increase the release point, counterclockwise to lower the release point.

8.  My Sentinel Relief Valve seems to leak some air, should this be happening?

The Sentinel Relief Valves will leak approximately 1 CFM in the closed state. This condition is inherent with spring-controlled valves utilizing a hard seal and is in no way detrimental to the performance of the system.   To the contrary, it provides a positive indication that the Relief Valve will perform properly if and when it is needed.

9. Is it important to put silicone sealant around the diaphragm bolt and retainer on the Model 350/500/100?

Yes. When replacing the diaphragm retainer (348-10) in the Model 350/500, first place a small amount of silicone sealant on the bottom edge of the retainer where it contacts the diaphragm back-up plate (348-16). Place a small amount of silicone sealant on the threads of the diaphragm bolt (348-30) and screw into the top of the shaft. On the Model 100 place just a small portion of sealant in order to seal the shoulder of the diaphragm bolt (353-10) to the back-up plate (353-07).

10. My vacuum controller seems to be oscillating.

To begin with, you need to determine whether or not it is truly oscillating. The best way to do that is turn the vacuum system on and leave the pulsators off. Now, open up a milk valve for about 1 or 2 seconds, then close the milk valve. If the controller is truly oscillating then the controller will take 15 to 30 seconds to settle down. If the controller responds to the leak quickly and maintains the set vacuum level then it is probably not oscillating. If the pulsators are running it is difficult to determine whether the controller is oscillating because the pulsation will cause the vacuum controller to operate by closing and opening, as it should and this movement might be misinterpreted as oscillation.

If it is oscillating then the first thing to do and in most cases the main reason for the oscillation is that the Mark II is not mounted on a two inch elbow or the Model 350/500 is mounted on something larger than a 3 inch elbow. It is important to have an elbow as mentioned above for the individual vacuum controllers in order that some back pressure is created and doesn't allow the controller to be too sensitive and thus oscillate.

The correct mounting procedures will be found in your parts and maintenance manual. But as a rule-of-thumb, always have a two inch 90 degree elbow at least 3 to 6 inches from the bottom of the Mark II and a three inch 90 degree elbow at least 3 to 6 inches from the bottom of the Model 350/500 Sentinel Vacuum Controller. 

11. Do the relief valves, 348-17 or RV-463, need to be set on a given system? I thought they were factory preset.

While it is true the relief valves are set at the factory it is dependant on the CFM of the vacuum system, so each relief valve should be set when put onto any vacuum system. The screw on the inside is turned clockwise to increase the release point and counter-clockwise to lower the release point.

12. What is the proper orientation of the poppet push-pin (406-07) and the rolling seal (406-14) when trying to assemble the two pieces properly?

Well, let's start with both parts:

The above rolling seal (406-14) is sitting on a table with what is called a square bead evident on the inside lip at the top of the seal. Now, let's look at the poppet push-pin below...

The next step is to insert the poppet push-pin (406-07) into the rolling seal (406-14) entering the rolling seal at the opposite end from the square bead. The square bead of the rolling seal will fit into the groove in the blue plastic part of the poppet push-pin, above. The result should look like the picture below:

13. Now that the poppet push-pin (406-07) and the rolling seal (406-14) are together properly, how is this assembly inserted into the flow ring (406-04L)?

First, the rolling seal (406-14) which is attached to the poppet push-pin must be flipped upwards like an umbrella that gets caught in a wind storm. Look below:

The above assembly now can be inserted into the flow ring (406-04L) and the square bead of the rolling seal which is now on the outside will fit the square cut out of the inside edge of the flow ring. See below:

Finally, the assembly should look as shown below:

14. My Sentinel Mark II appears to be controlling vacuum OK, but it seems to be vibrating alot and making a noise like a fog horn, occasionally. The problem possibly is that the rod seal that is pressed into the center of the Flange (406-33L) has worn to the point where it no longer applies the proper friction to the rod, which makes up the poppet push-pin (406-7). The rod seal applies friction to the movement of the poppet push-pin as it moves up and down. It, in a sense, dampens the movement of the push-pin in order to create a more stable condition. Without this friction on the push-pin the unit may become unstable. The best solution is to replace the Flange which would have a new rod seal in its center.

The amount of friction that is applied to the push-pin is somewhat subjective (in trying to communicate to someone who is in the field assembling or disassembling the unit) in that it's difficult to say exactly how much friction is the correct amount of friction. One way to determine if there is enough friction applied by the rod seal on the poppet push-pin is that when the unit (Mark II) is apart, insert the poppet push-pin into the Flange. Then carefully point the push-pin towards the ground. If the Flange stays on the push-pin without falling off, the friction is fairly certain to be correct.

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 Copyrightę 2010 L. J. Engineering, Inc. All rights reserved. Revised: June 8, 2010