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Troubleshooting Vacuum System Problems

Please complete the following initial checks:

- Make sure the electrical outlet is working. Plug a lamp or hair dryer into the outlet to be sure it is working.
- If there is no electricity to the outlet, check RV breaker. It may be tripped and need reset.
- Check to see if the filter bag is in place and if it needs replaced.

Click the problem below to go direcly to the troubleshooting section you need:
Vacuum will not turn on.
Unit runs, but won't shut off.
Unit runs, but no suction.
Unit runs, but low suction.
Unit turns on by itself, then shuts off by itself.

 

PROBLEM: Vacuum will not turn on.

Step 1 - Did Vacuum stop during vacuuming?

Yes – Vacuum may be overheated. Wait for Vacuum to cool (15-20 minutes). Unplug power supply cord from wall outlet and plug back in. If Vacuum runs, there is probably an obstruction of some kind within the system that is not allowing adequate airflow through the system, causing it to overheat. This unit uses the air moving through the system to cool the motor.

No
– Go to step 2

Step 2 – Was there recently a power surge within the coach?
Yes – The Relay protects the motor from a power surge. If you are certain there was a power surge, and another appliance like a microwave was also damaged, then you need to replace the Relay (7090).

Not Sure
- If you are not certain there was a power surge, go to step 3.

No
– Go to step 3

Step 3 –Test fuse.
Some older Vacuum units were equipped with a fuse. Remove and test this fuse with an Ohmmeter. If good, re-insert existing fuse and go to step 4. If bad, replace fuse (8011). If vacuum unit still does not run or the vacuum you are working on does not have a fuse then go to step 4.

Step 4 – Test low voltage wiring (these wires carry 24 volts and will not shock you).
Unplug 120-volt power supply to vacuum. Locate the low voltage wires that run from the main vacuum unit to each valve location. There is a connection made to these wires approx. 6” from main vacuum unit that connects the vacuum system wiring in the coach to the main vacuum unit. Remove or cut these connectors to expose 2 black bare wires from the main vacuum unit (See fig.2). Connect these 2 black wires together (see figure 3) and Plug in 120-volt power supply.

Figure 2  Figure 3

Does the unit turn on?
Yes –
This indicates that the main vacuum unit is functioning properly.  The problem exists in the wiring or valves within the coach.  Replace wire connection at main vacuum unit and go to step 8 for further troubleshooting.

No –
Go to step 5

Step 5 – As the unit is being plugged in, listen closely for a light clicking sound within the main vacuum unit.

Do you hear the clicking sound?

Yes –
This indicates that the relay board is working correctly and sending power to the motor. Replace wire connection at main vacuum unit and go to step 6.
No –
This indicates that the relay board is not functioning properly. Replace wire connection at main vacuum unit and go to step 7.

Step 6 - Unplug power source to power unit. Remove motor compartment cover by removing 2 Phillips head screws. If the 2 wires from the motor to the relay are connected, and not broken or pinched, the motor is bad.  Replace motor.  (See section 3.)

Step 7 - Unplug power source to power unit.  Replace relay board (7090).  (See section 4.)

Step 8Check inlet valves. Plug in power cord.  Remove valve from wall, but don’t take the wires off.  Use a screwdriver to “jump” the wires on the back of the valve (screwdriver touches both wires at the same time).

Does the unit turn on?
Yes – If the unit runs, the valve is bad.  Replace valve.  (Valves are typically “fully automatic” and the unit should run when the valve is opened.)
No –
Low voltage wiring is bad between valve and main vacuum unit.  Repair or replace faulty wiring.

PROBLEM: Unit runs, but won’t shut off.
This is usually because the relay is damaged (stuck in the closed position). When the relay is stuck in the closed position, lightly tapping on it with a screwdriver handle can sometimes release the contacts.  If this doesn’t work, replace the relay.

PROBLEM: Unit runs, but no suction
This is usually because a hose connection has come off.  Check all hose connections.

PROBLEM: Unit runs, but low suction.
Check hose connections for leaks.
Check hoses for clogs.
Check for crimped, twisted or pinched hoses.
Check filter bag.  Does it need replaced?
Check secondary filter and filter support (The Filter Support is a piece of black, porous material that goes between the Secondary Filter and the motor.  If these two parts are reversed, it severely limits airflow and can cause the motor to overheat.)

PROBLEM: Unit turns on by itself, then shuts off by itself.
This is usually because the screws attaching the valve to the wall are:

Over-tightened;
This causes the valve to “cave in” so the door doesn’t seal properly.  The system turns on, the vacuum closes the door, and the unit shuts off.

Too loose;
If the screws work loose, they hold the door slightly open, causing the unit to turn on.  The vacuum closes the door, and the unit shuts off.

An inlet valve may also be malfunctioning.  (See Step 8 – Check inlet valves)

 

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