Evoqua CAPAC 90W12D - Determining the Difficulty

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102808_CAPAC_MANUAL_MODEL_90W12D_SYSTEM.doc
Determining the Difficulty
The following procedure will help to localize difficulties in a CAPAC
®
system.
a) Check for 12 V DC voltage at controller input terminals.
b) Check reference electrode (Par. 1 or 2 below).
c) Check anode (Par. 1 or 2 below).
d) Check CAPAC
®
Monitor meter (Par. 3 below).
e) Check Dee Cee Tran Voltage Converter ( Par. 4 below) (if installed)
f) Check operation of the controller by determining if a variation in reference cell
input voltage changes the anode current (Pat. 5 below).
1. With the hull afloat all of the cables disconnected from the controller: An
unpainted reference electrode develops a voltage between its lead and the
hull or fittings, which may be measured with a high impedance (20,000
ohms/volts) DC voltmeter. This voltage will usually lie between 9.1 and 1.0
volt depending on the type of hull material and the degree of protection
provided to the hull, as listed in Section II. The hull will be negative (-) and the
reference electrode positive(+). On some unprotected wooden hulls, the
voltage may be zero or negative. The presence of this voltage shows that the
reference electrode is not shorted and that the wire is not broken. An anode
develops a voltage to the hull of 0.3 to 2.0 volts when disconnected from the
controller. A properly installed anode will always develop a higher voltage
than a reference electrode on the same hull.
2. With the hull out of the water and dry, and all leads disconnected from the
controller: An ohmmeter will indicate a high resistance (greater than 10,000
ohms) when connected between the anode or reference electrode lead wire
and the hull or fittings. Lower reading will be observed if the anode, electrode,
or cables are wet due to the voltage generated by these elements. The cables
connecting the anode and reference electrode to the controller can be
checked for continuity by shorting the controller ends of the cables to the hull
and checking for continuity between the face of the anode or electrode and the
bare hull. Proper installations will show a reading of 1 ohm or less. A higher
reading indicates poor connections, or in the case of wood hulls, poor bonding
of fittings to the negative terminals of the power source.
3. The meter of the CAPAC
®
Monitor read 1.0 volt full scale between terminals
(+) and (-). The meter can be checked by using 1-1/2 volt battery, dividing
resistor, and another DC voltmeter.
4. The Dee Cee Tran Voltage converter will produce 12.6 V DC at its output
terminals when 24 to 32 V DC s applies to its input terminals.