the water quality and conductivity in your boiler is extremely important. Learning how to properly install and maintain your boiler conductivity
electrode will help improve the performance of your boiler. Avoiding excessive
blowdowns will save water and chemicals and could lengthen the overall life of
Installing a Boiler Conductivity
Below are key points to help ensure proper operation when
installing a boiler conductivity electrode.
- Make sure the water level in the
boiler is at least 4-6 inches above the surface blowdown line.
- Maintain the manufacturer's
recommended pipe ID with no flow restrictions from the shut off valve to the electrode.
Minimizing the usage of tees, valves, elbows or unions between the boiler and
the electrode will help minimize the possibility of the sample water flashing.
- Install a full port manual shut
off valve at the boiler so the electrode can be removed and cleaned. Be sure to
keep the distance between the valve and electrode as short as possible.
- Mount the electrode in the side
branch of a tee in a horizontal run of pipe. This will minimize entrapment of
steam around the electrode and will allow any solids to pass through.
- There MUST be a flow restriction
after the electrode and/or control valve to provide back pressure. This flow
restriction will be either a flow control valve or an orifice union. The amount
of the flow restriction will affect the blowdown rate as well, and should be
sized accordingly. Refer to your manufacturer's recommendations for sizing.
- Install the motorized ball valve
or solenoid valve per the manufacturer’s instructions.
- For best results, align the hole
in the conductivity electrode so that the direction of water flow is through
Maintaining Conductivity Electrodes
of your conductivity probe is critical to maintaining the proper cycles of
concentration in your boiler. The
easiest and most effective way to calibrate your probe is to spot check your
boiler conductivity sensor with a calibrated handheld meter. The meter is calibrated using a conductivity
a manual reading several times per week and compare it to the conductivity
probe. If the reading is off by more
than 10%, a calibration is necessary.
The actual calibration method depends on your controller. Most have the option to do a one-point
process calibration. Follow the
instructions for your controller and input the reading from your manual test.
you have a hard time calibrating the probe or the readings between the sensor
and manual test are excessive, then it may be necessary to clean the sensor.
removal of scale or iron deposits, dip in a dilute hydrochloric or gallic acid solution, and
oils (including fingerprints!) wash with a detergent.
cleaning, it may be necessary to recalibrate the electrode.
or unstable conductivity readings could be due to a variety of conditions. The
following is a guideline and as always, consult your equipment’s manuals for
the manufacturer's recommendations.
- Try cleaning and recalibrating your electrode.
- Check to see if the sample is flashing. Close a
valve downstream of the electrode. If the reading climbs and stabilizes over
the next few minutes, more than likely the sample is flashing.
- Check the manufacturer's installation
recommendations to ensure that the electrode was installed correctly. Key
things to check are the electrode distance from the surface blowdown shut off
valve, minimal fittings between the shut off valve and the electrode, pipe size
(no restrictions) and the throttling valve setting.
If the electrode is clean, the sample is not flashing and the
plumbing is correct, but the conductivity is not reading correctly, perform the
- Remove the electrode and place it in a beaker of
boiler water with a known conductivity value. Note – Some controllers will read
conductivity only when it's “sampling”. If the controller is set up in
“Intermittent Sampling” mode, you must initiate the sampling mode for the
controller to begin reading the conductivity.
- If the conductivity reading matches the sample,
connect a wire between the beaker of water and the pipe. If the conductivity
value changes (usually lower), there is a ground loop and there may be a
problem with the electrode wiring. Contact the Manufacturer for assistance.
- If the
installation is satisfactory, the next step would be to check the electrical
Other Potential Problems
leaking: Occasionally the electrode could leak boiler water into the
internals of the electrode. Carefully examine the electrode and junction box
for signs of leakage.
element: If the temperature reading is the problem, follow the
Manufacturer's directions for testing the conditioning card, the electrode and
the controller’s sensor card. There are multiple possibilities for the issue,
performing a few simple tests will help you determine exactly where the problem
issues: Even though all wiring may be properly installed, a potential
problem with the controller ground may be the cause of the calibration problem.
Have a qualified electrician check to see if the power panel the controller is
connected to is properly grounded. Removing the electrode from the process and
placing overnight in a beaker of standard solution can also verify this. If the
reading drifts, improper grounding of the controller may be the problem. If it
does not drift, the process itself may be poorly grounded.
maintenance of your boiler conductivity electrodes will help improve the
performance of your system. If you have any questions regarding your equipment
reach out to the WatertechApplications Team at 414-377-4612.
We are always happy to help.