How To Use A Dwyer Slack Tube Manometer

As someone who thoroughly enjoys DIY projects, I am constantly in search of equipment that can simplify my work and enhance efficiency. Recently, I stumbled upon the Dwyer Slack Tube Manometer, a tool that has quickly become one of my favorites. This convenient instrument enables me to precisely gauge the pressure variances across different systems, proving to be a crucial asset for those engaged in fields like HVAC, plumbing, or automotive tasks.

What is a Dwyer Slack Tube Manometer?

A Dwyer Slack Tube Manometer is a simple yet effective pressure measuring device. It consists of a U-shaped glass tube filled with a colored liquid, typically water or mercury. The tube is bent into a U shape with one end open to the atmosphere and the other end connected to the system being measured.

When pressure is applied to one side of the tube, the liquid is displaced, causing the liquid levels on both sides to change. By measuring the difference in liquid levels, we can determine the pressure difference between the two points.

How to Use a Dwyer Slack Tube Manometer

Using a Dwyer Slack Tube Manometer is relatively straightforward, but it’s important to follow the correct steps to ensure accurate readings. Here’s how I typically go about using it:

  1. Prepare the Manometer: Start by filling the U-shaped tube with the appropriate liquid, making sure it reaches the same level on both sides. Water is a common choice for most applications due to its availability and safety.
  2. Connect the Manometer: Next, connect one end of the manometer to the system you want to measure. This can be done using a rubber hose or other suitable connectors. Ensure that the connections are tight to prevent any leaks.
  3. Take the Reading: With the manometer connected, observe the difference in liquid levels on both sides of the tube. The difference in levels represents the pressure difference in the system. Make sure to read the measurements at eye level to minimize parallax errors.
  4. Calculate the Pressure: Depending on the specific application, you may need to convert the liquid levels into pressure units using the appropriate conversion factors. Consult the device’s manual or refer to relevant standards for guidance.

It’s worth noting that using a Dwyer Slack Tube Manometer requires some practice to obtain accurate readings consistently. Take your time and familiarize yourself with the device’s operation before relying on its measurements for critical applications.

Personal Tips and Commentary

Having used the Dwyer Slack Tube Manometer for a while now, I’ve found a few tips that can help improve your experience with this tool:

  • Keep the Tube Clean: Over time, the tube may accumulate debris or residue, which can affect the accuracy of your measurements. Regularly clean the manometer to ensure clear visibility of the liquid levels.
  • Consider Using a Digital Manometer: While the Dwyer Slack Tube Manometer is a reliable and cost-effective choice, digital manometers offer additional features such as automatic pressure conversions and digital displays for easier readings.
  • Calibrate Regularly: To maintain accuracy, it’s important to calibrate your manometer periodically. Follow the manufacturer’s recommendations or consult a professional calibration service for guidance.


The Dwyer Slack Tube Manometer is a versatile and reliable tool that can greatly assist in pressure measurements as well as furnace high limit switch issues. And if you need a new furnace installation, make sure to contact professional HVAC techs who can provide professional furnace installation in North Florida. You may hire rochester ac maintenance and furnace repair contractors to service your unit. And if you need circuit breaker repair, make sure to contact the professionals. Check out sites like for additional guidance on HVAC repairs. Whether you’re a professional like Hargrove-Neel or Affordable Air Solutions in the HVAC industry or a DIY enthusiast like me, having this tool in your arsenal can make a world of difference. Just remember to follow the proper steps, practice, and keep your manometer clean to ensure accurate readings. Happy measuring!