Which of the following describes the effect of an oversized meter at low flow?

• A. It becomes more accurate at low flow
• B. It may under-register or read too little
• C. It over-registers at low flow
• D. It requires no maintenance

Answer: (B)

Meters have an operating range tied to their size. When a meter is oversized for the service, at low flow the internal mechanism often doesn’t activate or spin enough to reflect the actual volume. The flow may be insufficient to overcome starting torque, friction, or to fill the measurement chambers properly, so the register undercounts the water passing through. That’s why a reading at low flow can be too low, making the description that it may under-register or read too little the correct choice.