Electrical Installation - Walchem WDP420 Instruction Manual

3.5

Electrical installation

The various standard wiring options are shown in figure 2. Your WPH series controller will arrive from
the factory prewired or ready for hardwiring. Depending on your configuration of controller options,
you may be required to hardwire some or all of the input/output devices. Refer to figures 3 and 4 for
circuit board layout and wiring.
Note: when wiring the optional 4-20 mA output or a remote interlock switch, it is advisable to use
stranded, twisted, shield pair wire between 22-26 AWG. Shield should be terminated at the controller
ground stud (see figures 3 and 4).
1. There are live circuits inside the controller even when the power switch on the front panel is in
the OFF position! The front panel must never be opened before power to the controller is
REMOVED!
If your controller is prewired, it is supplied with a 8 foot, 18 AWG power cord with USA
style plug. A tool (#1 Phillips driver) is required to open the front panel.
2. When mounting the controller, make sure there is clear access to the disconnecting device!
3. The electrical installation of the controller must be done by trained personnel only and
conform to all applicable National, State and Local codes!
4. Proper grounding of this product is required. Any attempt to bypass the grounding will
compromise the safety of persons and property.
5. Operating this product in a manner not specified by Walchem may impair the protection
provided by the equipment.
POWER
CTRL 1
CTRL 2
CAUTION
ALARM
PLUG
CTRL 4
CTRL 3
Figure 2a WPH410 Conduit Wiring
4-20mA #2
(OPTIONAL)
pH/ORP
SENSOR
7
4-20mA #1
(OPTIONAL)
FLOW SWITCH
(OPTIONAL)