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Vacuum Troubleshooting 101

Vacuum deviation alarms are one of the most common alarms to get on your Lely robot and that really sucks. Most of the time a hose has slipped off or the impellers in the pump are seized and need a cleaning, but sometimes it’s not that easy.

If you are struggling with vacuum issues, then here is a list of things to check before throwing in the towel. NOTE If any work is being done on the pump side of the vacuum system, be sure to turn off the breaker in the central unit for the pump before working on it.

How to test vacuum at the robot

  1. First thing to do is go to your robot and enter the test menu.

  2. From here go to 'Mothership' then 'Other' and close the pre-milk.

  3. From here go to 'Pulsator' then 'Controls' and close all 4 of the vacuum valves.

  4. Lastly, go to 'Vacuum Pump' and turn on the pump in the test menu.

Vacuum doesn't move from 0kPa

  1. Listen if the vacuum motor has turned on (there should be some noise).

  2. If no noise is coming from the central unit, then check the breaker (possibly tripped).

  3. If the breaker is on and there is no noise check for a fault code on the VFD (Common fault codes are OL1, OL2, uV, etc.).

  4. If alarm codes on the VFD are present, then turn off the breaker for 30 seconds and turn it back on (Does the code come back or does the pump fire on and build up vacuum ok?).

  5. If the code comes back then most commonly there is a plugged area in the vacuum system, a seized pump, or a leak and is causing the pump to work harder then it should, resulting in an overload alarm (refer to images at the end for commonly plugged areas).

  6. If the pump is seized and not spinning, then take off the head of the pump and clean the impellers (a damp Scotch-Brite pad usually does the trick).

Vacuum reaches 42kPa, but takes more than 15 seconds

  1. This is typically caused by small leaks, plugged vacuum system, or and old worn-out pump.

  2. If leaks are heard, then try to find where they are coming from and fix.

  3. If no leaks are heard, then these are 4 of the most common areas to be plugged up (refer to images at end for commonly plugged areas):

    1. Vacuum buffer manifold

    2. Muffler (or muffler hose)

    3. Neck on top of vacuum pump

    4. Cone valve on robot

  4. If there is no plugged up areas or leaks, then its possible that the pump is worn out (typically a 10-12 year life span).

Vacuum is present, but doesn’t reach 42kPa (10-30kPa typically)

  1. If your vacuum is building up slowly and not reaching the 42kPa then most likely a hose has slipped off (the pump will also be running at full speed most likely).

  2. Check the 6-fold hose connections at the robot arm.

  3. Check milk hoses inside the robot arm.

  4. The pre-milk could possibly be damaged or have had a silicon cuff slip off.

  5. Is there vacuum leaking out of the cup (possibly a sticky shut-off valve or bad solenoid)?

If vacuum system reaches 42kPa within 0-15 seconds, then check the following

  1. If it does reach vacuum and seems to be operating normally, then it’s not a bad idea to go back and open 1 vacuum valve at a time and see if there is vacuum at each individual cup (maybe a hose or twin tube has slipped off).

  2. While doing the tests at the cup be sure to loosen the cup and make sure there is no slits in the twin tube.

  3. Possibly a damaged pre-milk plastic.

If the vacuum reaches 42kPa, but continues to go upwards towards 50kPa.

  1. If the vacuum continues to build up more than 42kPa and takes a while to settle back down, then most likely this is caused by a plugged up vacuum system.

  2. Check the 4 common plugged areas:

    1. Vacuum buffer manifold

    2. Muffler (or muffler hose)

    3. Neck on top of vacuum pump

    4. Cone valve on robot

  3. Another thing that can cause this is worn out bearings in the cone valve. Images of common issues found in the field

Figure 1: Plugged vacuum neck (take off and clean)
Figure 1: Plugged vacuum neck (take off and clean)

Figure 2: Muffler (take apart and clean as well as muffler hose)
Figure 2: Muffler (take apart and clean as well as muffler hose)

Figure 3: Plugged cyclone (take off and clean)

Figure 4: Plugged cyclone (clean)

Figure 5: Gummed up cone vale (clean)

Figure 6: Broken pre-milk (don't use clamps on plastic)

If more help is needed, call the on-call line for further support.

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