1. When I went to use my meter for the first time this year it was stuck. What can I do? Although your meter is designed to require little or no maintenance, the residual material left when a fluid dries in the meter can jam the close tolerance disc within the chamber. See the procedure recommended for cleaning the meter in the Guide packed with the meter. Generally a thorough cleaning will restore the meter to full operation. 2. Is this meter approved for commercial use? This meter mechanism is capable of high accuracy, typically 0.5%, if operated under steady flow rate and calibrated at that rate. This capability however does not meet the requirements of the Weights and Measures Departments in most states and they therefore will not approve this meter for use for the resale of liquids. 3. What do you mean by a "positive displacement meter? A positive displacement meter allows a VERY specific volume of fluid to move through the meter with every rotation of the mechanism. Conversely if the mechanism of a positive displacement meter is held, there should be no flow through the meter. That VERY specific volume is determined by the designed size of the meter chamber and allows the rotating meter shaft to be tied to a counter which indicates the count of rotations as the volume of fluid passing through the meter. By varying the gear ratio tying the chamber to the counter, the same chamber can be used for two different units of measure, like gallons and liters. 4. How can I be sure my meter is operating properly? After zeroing the meter, fill a container of known volume and compare the indicated volume to the measured volume. As simple as this method seems it is used universally as the absolute calibration means by all requiring accurate meter indication. A container used for this type calibration is described as a "proving can" and the use of a proving can 5X the major unit of calibration is recommended. In the case of the 800 meter, where gallon is the most common unit of measure, a five-gallon proving can is recommended and generally can be obtained from the dealer where your meter was purchased. 5. What limits the flow capacity of this meter? The forced flow of fluid through the meter results in a pressure differential measured across the meter, and the higher the flow through the meter, the higher that pressure drop across the meter. While the increase in pressure drop is close to linear with the increase of flow over a considerable range, that linearity is lost at the upper flow levels because of the physical size of the chamber and the ports into and out of the chamber. The upper limit where that linearity is lost is normally taken as the upper flow limit of allowed operation.