A residential home had a nice garden with a new watering system recently added by a contractor.
The main water (at 60 pounds per square inch gauge [psig]) supply pipe comes from under the ground, as shown in Image 1 (on the right). The water can go to the right (to the house) and/or to the left and under the ground, coming out further to the garden watering control valve system, which is also shown in Image 1 (at the corner of the property).
IMAGE 1: The main water supply pipe comes from under the ground (Images courtesy of the author)
Image 2 shows when there is usage of water (red line) by people in the house while the garden system is not active. Meter M1 (on the right) measures water usage for the house, and meter M2 measures water usage for the garden. The M1 dial shows the movement of the digits registering the usage, while the digits of M2 are not in motion, as the garden is not being watered.
IMAGE 2: Usage of water by the house only
When the garden watering system kicks in, water flows to the garden as shown in Image 3, and the garden water meter M2 digits move, confirming the water is flowing to the garden. However, when the owner received the water bill, it showed higher water usage than anticipated. When he observed the system during the watering cycle, he noticed the house water supply meter M1 dial was also moving even when no water was consumed in the house. Why?
IMAGE 3: Usage of water by the garden only. Why do the house meter (M1) digits also move?
The owner called the contractor to find out what was going on. What do you think he found?
What do you think happened, and how did the contractor solve the problem?
The best answer will be published in an upcoming issue of P&S.
Note: Dr. Nelik conducts a periodic Pumps Live Troubleshooting Course focused on learning pump theory and applications by solving similar actual pump problems, which are solved in class by the attendees. To register or schedule, email drpump@pumpingmachinery.com. Solution to your pump problem is guaranteed.