Here are some basics steps to troubleshoot a central vacuum system with low suction:
There are a few issues that can cause a central vacuum system to have low suction. You will want to first check the suction directly at the power unit to determine if the unit is the problem. If the unit has great suction, then the clog is in the pipes or the hose. For instructions on removing a clog that is in the pipes or hose click here for steps to unclog a central vac.
If you have poor suction at the unit, the first thing you can check is if your central vacuum bag is three fourths or more full. If it is, replace the bag and test the unit again.
If the central vac bag is not full or if replacing the bag didn’t work, check to see if the cloth filter, foam filter, or screen is clean and free of debris. Sometimes there are secondary filters past the initial filter. If the secondary filter appears clogged, try cleaning it off or replacing it before testing the unit again.
Another step you can take is to check that the power unit gaskets are in good condition and correctly installed. There is usually a large gasket that joins bottom emptying buckets to the vacuum body.
If your system has more than one motor, one of the motors could have failed and needs to be replaced. It may appear that a motor is working because it is spinning, but it may just be the air flowing through it. If you test a motor, be sure it runs without shutting off for 20 minutes. Click here for more information on how to replace a central vacuum motor.