CAUTION: There are live circuits inside the controller even when the power switch is in the
OFF position! Servicing and troubleshooting the controller must be performed by Qualified
Service Personnel.
4
Section 2 (A):
WEL-PH Housing
+ Electrode Reading is Stuck on one Value
Step 1:
The following are normal (expected) readings when the controller electrode input is programmed as pH,
and the following configurations are in place:
With nothing connected to the electrode input terminals in the controller, the reading should
be about 0 mV (7 pH).
With just the WEL-PH housing wired into the electrode input terminals in the controller (but no
electrode installed), the reading should float (vary low to high to low to high, etc.).
With the WEL-PH housing wired into the electrode input terminals in the controller, and the
electrode threaded into the housing, the reading should be the pH value of the solution, as
verified by a secondary means, such as a handheld pH meter.
Step 2:
If a controller’s electrode input is programmed as pH, and the controller has a WEL-PH housing wired
into the correct electrode input terminals (with the electrode threaded into the housing), and the pH
reading is stuck on some incorrect pH value, please check the following:
There could be an electrical short between controller input terminals IN+ and IN-
•
Either the electrode wires, or electrode cable wires, are contacting each other when they
normally should not be.
The glass on the end of the electrode could be broken or compromised.
There is an open circuit between controller input terminals IN+ and IN-
•
This could mean the electrode/electrode cable has broken wires.
