Given the interest and discussion last year when we looked at a few operation and maintenance questions, I thought we would ask a few questions to give some more practice.

1. If you are evaluating a pump tank and pump system, and you measure the dimensions to be 49 inches wide by 68 inches long by 62 inches deep, calculate the gallons per inch.

2. If the pump runs for three minutes and the effluent levels change from 66 inches to 73.5 inches, what is the pumping rate for the system?

3. If the system has a check valve and the required dose volume is 75 gallons, how long should the timer be set for the “on” setting?

4. If the number of cycles required for the system was six times per day, for how long should the “off” time be set?

5. If the timer was set to pump six times a day and the cycle counter read 3,442 today and read 2,899 on the last visit 120 days ago, is this system operating properly?

6. The elapsed time meter (ETM) reads 215.8 hours today. On the last visit 120 days ago, the timer read 192.6 hours. What is the total time recorded in minutes?

7. What is the total flow and average flow for the 120 days?

If you missed it, here's a brush-up on Simple Septic Math to review first. 

Answers are posted here. 

This article is part of a series of practice problems for installers:

• Onsite Arithmetic: Is This Tank Large Enough?
• Onsite Arithmetic: Cylindrical Tanks
• Onsite Arithmetic: Setting Floats
• Onsite Arithmetic: Flow
• Onsite Arithmetic: Flow - Part 2
• Onsite Arithmetic: More O&M Practice
• Pointers for Onsite Arithmetic