Sebo G-SERIES Guide

“G” Series – By Pass Valve Replacement Instructions
This manual is intended to assist in replacing the by-pass valve in the SEBO
“G” series machines.
Remove the entire bag housing from the machine. Remove the two screws
holding the power head cover from the motor unit.
Refer to the Schematic and parts list for location of parts on the machine.
Locate the support lever and spring (5129 & 5107-1) See photo.
Support Lever – Motor pulley cover
Pull the lever back towards the rear wheels and lift up on the black motor
pulley cover (5115SW) to remove it. Release the support lever spring and
slide the support lever and spring out of its bushing in the chassis. Slide the
5463 belt off the motor pulley.
Remove the (4) screws holding the turquoise motor cover (2826TK). Set the
cover aside.

Take note of how the wiring from the motor, and electronic control board
are positioned on and around the air channel cover (2839SW). See photo.
Location of wiring to motor and pc board
Remove the motor wiring harness from terminals M1 and M2 on the side
power supply pc board by pulling up on the “T” shaped connector. Lift the
motor and wiring from the chassis. (NOTE: THE MOTOR HAS A
THERMAL PROTECTION DEVICE FACING THE REAR OF THE
CHASSIS. WHEN REPLACING IT MAKE SURE OF IT’S CORRECT
POSITIONING).
Un-plug the flat ribbon cable from the electronic control board going over to
the power supply board.

Remove the two screws holding the air channel cover. (2839SW). Lift it up
and off of the suction neck assembly.
Air channel cover ( 2839SW)
The spring loaded thrust member (2834) may have popped out of its position
on the suction neck support and jumped forward. If not, grab hold of the top
of the shaft and slide it to the left and out of the support. It will spring back
towards the front of the machine. See photos.
Photos showing the position of the thrust member (2834)
Un-plug the tiny red wire connecting plug from the circuit board (K1 & K2).
Remove the black and white wires from terminals L & N from the power
supply PC board. Remove the single screw holding the printed circuit
board and then lift it up and towards the back of the machine to remove it.

With the suction neck in the up and locked position, insert a small ¼” flat
blade screwdriver into the slot behind the black RH suction neck support
(2824) (closest to the wheel. Pry the notch away from the support while
pulling up on both of the black supports. See photo below.
Location of the release lock for the suction neck assembly
The suction neck assembly should now come out of the chassis. If it is not
free, insert the screwdriver into the slot just behind the LH support (5479)
and pull up on the entire neck assy. See photo above.
Remove the black and white wires from their respective grooves coming out
of the suction neck assembly and slip off the RH suction neck support.
(2824) Remove the LH support from the opposite side and set them both
aside.

Remove the black swivel neck bearing (2825) by pulling it forward. Note
how the clear by pass valve is positioned within the suction neck
assembly. The two red wires must be in the rounded grooves and exit
through the cutout slot when re-assembling the unit. See the next photo..
Notice how the wiring follows the curvature of the valve
With your fingers or a pair of long nose pliers, grasp one of the red wire
terminals and gently pull out the valve assembly. (2835).
The following paragraph describes how to take the valve apart to clean it. If
you are just replacing the old valve you can skip over this part.
The by-pass valve in your unit is clear. I have colored certain parts
mentioned in this Tech manual just for instructional purposes.
Pull off the two red wires from the terminals. Hold the by pass valve as
shown in the photo.

The plastic tab (colored red) is lifted and pulled up and away from the base
cover of the valve. (colored blue)
Remove the center plunger and larger spring. Refer to the following
photographs to continue the disassembly of the valve.

Using a small flat blade screwdriver to release the tabs (colored green)
Hold the rounded part of the valve in your left hand. Place a small flat blade
screwdriver over the two tabs (colored green) on the right side and push
down on both tabs consecutively to release the back of the housing. Do the
same thing with the other side. Separate the two pieces. Remove the brass
contact plate and small spring. See photo of compromised (dirt filled) valve.

A dirty by pass valve
Clean the valve with compressed air. NOTE: If you notice any corrosion
on any copper or brass part of the valve, it will need either a good
cleaning or replacement. Re-assemble the by pass valve and test it with a
screwdriver pressed into the center slot of the plastic plunger to make sure it
moves freely all the way in and out. Replace the red wires. Re-insert it back
into the suction neck assembly making sure that the red wires are not
pinched, or out of their respective grooves.
Re-install the suction neck assembly, air duct channel cover, motor, motor
cover, and support lever. Once all the parts are back in place you will need
to re-adjust the full bag indicator by following the instructions below.
Replace the bag housing on the motor unit.

How to adjust the bag full indicator on the SEBO Essential G Series
The bag full indicator on the Essential G Series is adjusted by turning a
spring loaded screw which is part of the bypass valve ( 2835 ). DO NOT
compress the spring any more than necessary as false readings may occur.
Use only enough pressure to engage the screw.
Before you begin:
MAKE SURE THAT ALL AIRWAYS ARE COMPLETELY FREE
FROM OBSTRUCTION.
Install a new filter bag ( 5093AM ), micro filter ( 5036AM ) and exhaust
filter ( 2846 ). You will need a small flathead screwdriver and a blue hose
cap ( 5429/BL ). The adjustment can be made with the power head cover on
or off as access has been provided on the suction neck side of the machine.
The vacuum must be in the upright position to perform these tests.
Functional tests:
Switch on the machine. Remove the hose ( 5040HG ) from the extension
tube, (5045HG ) and place it along side of the machine. Turn the machine
on and place the blue hose cap on the hose. Keep hands clear of hose cap.
IF THE BAG FULL LIGHT COMES ON:
Switch off the machine and turn the adjusting screw on the bypass valve
counter clockwise slightly, a quarter turn may be too much. Switch the
machine back on.
Continue the above until the bag full light remains off while the machine is
running with the blue cap on the hose.
Now that the bag full light is off when the bag is empty, you must test to
make sure the bag full light will come on as designed. With the blue hose
cap on the hose and the machine running, cover the big hole on the blue hose
cap with your thumb. The bag full light should come on.
IF THE BAG FULL LIGHT DOES NOT COME ON:

Switch off the machine and turn the adjusting screw on the bypass valve
clockwise slightly, a quarter turn may be too much. Switch the machine back
on.
Continue the above until the bag full light remains on when the machine is
running with the big hole on the blue hose cap covered.
Repeat both tests to ensure that the valve has not been adjusted too far one
way or the other.
If you do not have a blue cap, perform the same test by placing your thumb
over at least 1/2 of the intake hole of the hose allowing about 1/2 amount of
air to enter the hose. As you cover more area; about ¾, the red bag full light
should illuminate. As you remove your thumb, the light should go out. Keep
in mind that this is a very coarse adjustment.