I have a SHP1900 or SHP2000 and the detergent function doesn’t work

To engage the detergent tank on either the SHP1900 or SHP2000 do the following:

1. Put hot water in the detergent tank.
2. Hook up power and water to the unit
3. Have the black Soap nozzle in the spray gun.
4. Turn on the water and power
5. Squeeze and hold the trigger for 10-15 seconds
6. While the water is flowing through the gun, squeeze the detergent tube above the detergent tank.
7. Hold the squeeze for 5-6 seconds
8. Release the detergent tube, continue squeezing the trigger so water continues to flow through the gun
9. Repeat this three times in succession.