Maximize Chemical Injector Pump Performance – Car Wash Industry


There are two primary pump classifications that spawn a multitude of subgroups, or branches. Displacement and dynamic are both essential pumps that are used throughout the carwash industry. Displacement pumps include two important categories, and further sub-categories:

1.) Reciprocating

  • Diaphragm
  • Piston

2.) Rotary

  • Peristaltic
  • Screw
  • Vane

Dynamic pumps also include two categories:

1.) Centrifugal

  • Axial flow (impeller)
  • Radial

2.) Special effect

  • Jet
  • Gas
  • Hydraulic

Carwashes today use the majority of these pumps. Centrifugal pumps, which are an essential asset in low water pressure areas, are used for pumping large amounts of water.Piston pumps are important in water reclamation and reverse osmosis systems.

Displacement style pumps, or more specifically reciprocating diaphragm, are the preferred way to pump carwash chemicals; rotary peristaltic pumps are also used for pumping specific chemicals.

Delivery pumps

These pumps are properly called displacement pumps. Remember, both reciprocating diaphragm and rotary peristaltic are often referred to, in the industry, as chemical dispensers, injectors, metering pumps, diaphragm pumps or chem-feeds.The rotary peristaltic is often referred to as a tube or squeeze-tube pump.

Most modern carwashes come equipped with chemical injector pumps as standard equipment. These diaphragm pumps inject precise amounts of carwash chemical into the wash line. The chemicals used vary; they could be soaps or various waxes, drying agents or under-car cleaners.









Displacement style pumps, being made here, are the preferred way to pump carwash chemicals.

These diaphragm injector pumps are not standard off-the-shelf pumps — they are a hybrid variety. These special injector pumps are required to start and stop, in some cases, hundreds of times per day.They are also required to:

  • Handle a wide variety of chemicals
  • Be completely adjustable
  • Handle wet environments
  • Be field serviceable.

Chemical injectors require periodic maintenance, with the amount of maintenance depending on the level of activity at the wash.

Get better performance

To maximizing your chemical-injector pump performance:

  • Avoid running chemical containers dry. While the pump may not be mechanically harmed, pumping air will cause the valves to build up a residue of dried chemical.
  • After changing out chemical containers, make sure the pump is primed and most air is purged out of the pump head.
  • Inspect and, if necessary, replace your diaphragm at least every six months. Also inspect the top and bottom valves — clean or replace as necessary.
  • Keep spare liquid ends (assembled pump head kits) handy. It’s far easier to replace a diaphragm and pump head complete with valves (usually just four screws) than it is to detail every o-ring and ball seat. Time is money.
  • Inspect your foot-valve strainer quarterly.
  • Chemical injectors are easy to prime when the discharge (pressure) line is removed or vented. After the pump is primed, reattach the discharge line to the top pump-head valve or close the vent relief.
  • Always wear eye protection when working on chemical injectors or when changing out containers.
  • Avoid changing chemical brands without researching the compatibility on your injector pumps.
  • A flow indicator installed on the suction tubing of your injector is an outstanding diagnostic tool. At a glance, you can see if the pump is working properly.


Robin Gledhill, President
Blue-White Industries
Huntington Beach, CA, USA