Chapter 4 – Smoke Control Section, Page 4-48_________________________________________________
Wash System – Troubleshooting (Cont.)
Line Strainer
The Line Strainer (Refer to Figure 4-48-1 and 4-48-2) prevents foreign material from going downstream
and causing the Reduced Pressure Principle Device, Solenoid Valves and the ClearAir water spray nozzles
to malfunction. If it is determined that foreign material is flowing downstream of the Line Strainer, the
strainer screen must be removed and cleaned. To clean proceed as follows:
1.
Turn off the hot water supply upstream of the Line strainer.
2.
Using a wrench, slowly unscrew the Screen Plug. Caution: The water may still be under pressure
causing the Screen Plug to blow off and water to discharge rapidly.
3.
Remove the Screen.
4.
Using a wire brush and hot detergent water, clean the screen.
5.
Replace the Screen, Screen Plug and tighten thoroughly.
6.
Test for leaks.
Backflow Preventer (Reduced Pressure Principle Device)
Overview
A Backflow Preventer is mounted within the Wash Control Cabinet and is required by code to prevent
contaminated water (water with detergent) from back-flowing upstream to potable water (Refer to Figure
4-41-1, and 4-49-1). The Backflow Preventer is manufactured by the Watts Regulator Company.
The Backflow Preventer consists of two Check Module Assemblies with spring loaded check valves and one
Relief Valve Assembly with a spring loaded relief valve. There is a shut off valve on the inlet and outlet
sides of the unit to allow servicing. This device prevents backflow by opening and closing the check valves
if the pressure from the inlet side to the outlet side of the device varies.
Figure 4-48-1
Line Strainer
Figure 4-48-2
Line Strainer With
Screen Removed
