Most ultrasonic scalers simply plug into a wall outlet for power but they also require water. They all have some sort of water line attachment and many include a male quick disconnect. The vast majority use a ¼” o.d. supply line to connect to water, but you should always measure what you have before purchasing the necessary components as there are exceptions.
Many units have existing female connectors already installed so connecting your scaler should be a simple matter of plugging it in (provided everything is the same size). But what if your unit doesn’t have a water connection for the ultrasonic? It’s a simple thing to add.
First, you’ll need to open the unit to access the internal lines. You’ll need to locate a live water line (this is a water line that is constantly under pressure). I've got a post on my blog showing the a-dec color codes which will tell you what to look for if you have an a-dec unit (https://www.dental-techguru.com/.../know-your-tubing-know...). If you have another brand, looking at the a-dec codes still may be helpful as many other manufacturers follow their lead, although not all, so exercise caution (or reach out to the manufacturer or to me if you are a subscriber). In general, water lines will be cool to the touch as they are fed from cold water lines (if using municipal water) or a bottle which is room temperature (if using self-contained water).
Once you’ve located a live water line, turn off the unit and depressurize the line by holding down the water button on your air/water syringe until the water stops. You can then cut the water line you located and splice into it using a “T” fitting. Generally, barbed fittings work well and are compact so you needn’t be too concerned about space. These properties are why I recommend barbed fittings rather than compression fittings. Barbs also tend to be less costly. If the live water line is a different size than your ultrasonic scaler requires, barbs also simplify adapting the size.
The “T” in the water will provide a feed which you can then attach to a female quick disconnect. Of course, you'll also need a short length of tubing to run from the "T" to the female quick disconnect. The female quick disconnect will provide an attachment for the water line from your ultrasonic scaler. Most females mount into a ½” diameter hole (again, measure what you have to be sure) so you may need to drill a hole in the unit face to mount it (many units have plugged accessory holes so you may just need to remove a plug). Be sure to push the female through the panel before attaching the tubing. The female will then be secured in place with a large nut inside the unit. Again, attach this nut before the tubing. The last step should be attaching the tubing to the female inside the unit as once the tubing is attached, the tubing will interfere with attaching anything else.