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5
SERVICE
To perform routine maintenance on system components, De Nora Water Technologies recommends closing the
manual line valves at the two independent chemical sources while continuing system operation to evacuate the
piping system of chemical. Such routine maintenance might include cleaning filters and vaporizers, and pressure
reducing valve repair.
5.1
Automatic Switchover
The Automatic Switchover electronics unit does not require routine maintenance.
5.1.1
Power Supply
a. The Automatic Switchover unit uses a fuse on incoming power and 24 Vac output power that can be
replaced.
b. The programmable controller displays power status on the front panel. If the programmable controller
displays a fault (see Figure 4), contact De Nora Water Technologies Service Department.
NOTE: Recording of indicators (see Figure 4) is very helpful in troubleshooting faults.
c. Control relays interface with the motorized ball valves and can be replaced if found faulty during service
and/or troubleshooting.
5.2
System Shutdown for Routine Maintenance
In addition to the following, refer to the manufacturers instruction manual for routine maintenance.
5.2.1
Complete System Shutdown for Maintenance
a. Continue dispensing system operation to evacuate the piping system of the liquid/gas being dispersed.
b. Close the manual line valves at the two independent chemical sources while continuing system
operation to evacuate the piping system of chemical.
c. Observe the system status lights on the Automatic Switchover. The OPEN light of the side which is
dispensing chemical will eventually go out and the EMPTY light on that side will illuminate indicating
that chemical between the source and the motorized ball valve has been exhausted. Automatic
switchover will occur and the chemical in the stand-by source will also be exhausted between the
source and the motorized ball valve. Both EMPTY lights should be illuminated and both motorized ball
valves closed.
d. Turn OFF power to the Automatic Switchover electronics.
e. Continue operating the chemical dispensing equipment as long as necessary to evacuate chemical from
the entire system.
NOTE:
In the case of vacuum type solution feed gas feeders, continue operating the gas feeder until
the float in the gas flowmeter drops to the bottom of the tube indicating no gas available. Turn OFF the
water supply to the ejector.
f. Open all safety switches and circuit breakers supplying electrical power to the system.
CAUTION:
The piping may still contain some potentially hazardous residual gas which should be
exhausted to a safe area.
5.2.2
Return to automatic operation.
a. Check any piping connections that have been disassembled for leaks before opening chemical source
manual valves. (Refer to sections 3.2.1, 3.2.2, and 3.2.3)
b. Apply power to the system.
c. Set mode switch to AUTOMATIC. (Refer to section 4.2.1)
