ATI
PQ45P pH System
Part 3
– Sensor Preparation
9
O&M Manual
Rev-B (7/15)
2.3
Internal Flow System
The “Wet” section of the analyzer is located on the back of the internal hinged panel. The panel
is held in place by two captive screws on the right side. Loosen these screws to get access to the
sensors and sample flow components. Figure 3 identifies the items located on the back of the
panel.
Figure 3 - Sensor and Flow Components
The flow system inside the case consists of quick-disconnect sample and drain fittings,
polyurethane tubing, flow control assembly, and a flowcell with pH sensor. This system is
completely assembled and is designed for connection to water sources with pressure between 5
and 75 PSI. Note that the drain tube MUST discharge to an unpressurized drain. You may not
connect the drain to a pressurized line or the system will not function properly.
Most tubing connections are made using what are called “instant tube fittings”. These fitting are
designed to allow tubing to be readily removed in case service is needed on a particular
component. This is normally only needed to remove the flow control assembly to clean the y-
strainer.
The instant tube fittings have a circular collar at the end of the fitting. This collar must be pushed
toward the main body of the fitting while pulling the tubing in the opposite direction. When
reinserting the tubing, simply press the tubing into the fitting and you will feel it slide into place.
