In this video, we’ll cover when and how to replace an EXO Central Wiper brush. Keeping the sensors free of fouling is very important to collecting accurate data and extending your sonde deployment. EXO Sondes use a reliable and effective central wiper probe to ensure sensors remain clean during unattended monitoring.
The EXO Central Wiper is compatible with two different wiper brushes: the standard brush that we have installed here and the NitraLED Wiper Brush that is designed specifically for configurations using the EXO NitraLED sensor. For more information on this, please check out the NitraLED installation video.
To remain effective, the brush will need replaced after a period of use. This period may vary depending on several factors including deployment length, frequency of the wiping interval, and site conditions. To recognize when your brush needs replaced, inspect the bristles after each use. A brand-new wiper brush will hold its bristles tightly together, as you can see here. With use over time, you will notice that the bristles will begin to splay. This is expected, and eventually, the wiper brush will need replaced. Here is an example of a brush that has lost its effectiveness due to splay and needs replaced.
To replace the brush, loosen the set screw with a 0.05-inch Allen wrench. Pull the old brush straight up from the wiper shaft. Be sure to clean any debris that may be present on the shaft and the top of the wiper probe. You can also take this opportunity to clean the wiper brush guard. You can use a toothbrush or pipe cleaner and warm water for this.
Next, we’ll install the new brush by placing it onto the wiper shaft and sliding it down as far as it will go. The brush is keyed to fit on the wiper shaft in only one orientation. Once it is seated, tighten the set screw with the same Allen key. Tighten until snug. If you have a torque driver, tighten the set screw to a torque of 4-inch pounds. You can check the snugness of the wiper brush by gently rocking 5 degrees in either direction. With that, your wiper brush has been replaced!
You can prolong the life of the wiper brush by thoroughly cleaning the bristles after each deployment. With the brush removed, we recommend running warm water over the bristles and using a toothbrush to clean any debris that may be present. After cleaning, we recommend placing a twist-tie around the bristles to help them retain their shape.
Some have had success greatly extending the life of their wiper brush by soaking it in hot water for a few minutes after cleaning, then tightly wrapping a twist-tie around the bristles and leaving it on as they dry.
Cleaning the brush is vital to minimize the risk of contaminating calibration standards after deployment. For efficiency, we recommend using a dedicated wiper brush for sensor calibration. In addition to a clean brush, also make sure that the brush guard is clean to avoid contamination.
Any time a brush is removed and reinstalled or replaced, it is good practice to check the parking position by initiating a wipe cycle. Here we are using Kor Software, but this can also be checked using the EXO Handheld or the Kor Mobile app.
With the wiper installed, simply connect the sonde, and navigate to the live data screen. Here you can activate the wiper. It should rotate twice in one direction and then twice in the opposite direction, parking with the bristles being relatively center of the brush guard.
If the parking position is off, you can adjust this by navigating to the Calibration screen, selecting the Wiper, and clicking Calibrate. You can select Jog Right or Left to center the wiper brush. Once you have centered, click Apply. We recommend activating the wiper again to double-check the parking position.
The wiper brush has now been successfully installed. Please check out our other EXO University videos, and thanks for watching!