Frozen Meters Exposed – Don’t Try This at Home

A water meter usually sits in a basement or crawlspace off in a corner, forgotten, and often ignored. But when temperatures start to dip below 0° F, and the water in the meter freezes because no one thought to keep their meter nice and toasty warm, this water measuring device starts to get a little recognition. Unfortunately for our city, we have had several water meters freeze and break this season. So the other day, T.J., our Neptune water meter sales guy, showed up to bestow some of his water meter wisdom upon us. I found this information fascinating since up to now no one had ever explained to me how meters respond when frozen. Thinking there might be others interested in frozen water meters (I know it’s a long shot), I decided to share what I learned with all of you.

Cracked Frost Plate on Water MeterHere is a photo of a water meter that has been turned upside down so you can see the black plate attached to the bottom. When water inside this meter freezes it expands exerting pressure on the top and bottom of the meter base. To relieve this pressure, this black plate, or frost plate, cracks because it is manufactured to fail at a lower pressure than the meter base casting. In this photo you can see the crack running across the plate (the black arrow has been added to highlight the location of the crack lying below).

Meter with Cracked Frost PlateIf you take off the frost plate by unscrewing the connectors, you will find a plastic cap as shown in this photo. This plastic cap is designed to bend and transfer the pressure from the frozen water to the frost plate.
Plastic Cap Removed
Removing the plastic disc reveals another plastic component. By looking closely, you can also see the gasket that lies between the meter and the plastic disc. Screen Lifted
In order to remove this black plastic piece, you need to pull up on a white, plastic screen lying inside the meter between this black piece and the inlet of the meter. This photo shows the screen partially removed.

Water Meter PartsIn these next two photos, I have removed all of the internal parts and laid them out. Remember, don’t try this at home! In the one photo, you can see a small portion of the chamber inside the black plastic piece. Water Meter PartsThis is where the water flows causing a disc inside to move, or “nutate.” This movement causes the magnet (the small disc attached to the black, plastic piece on the right side) to register the measurement with the reading device attached to the top of the meter.

And just to be sure I had the whole thing torn apart, I opened up the black plastic piece. Here you can see the little disc still lying inside the piece on the right. Nutating DiscThe piece on the left rotates or nutates along this disc. This movement is actually what is used to measure the amount of water flowing through the meter.

So what is the point of all this, other than I got to tear apart a meter? Well, I learned about the frost plate and its purpose. I also learned that if the frost plate breaks as designed, and all these internal parts appear to be ok, then we can just purchase a frost plate and put the meter back together. We could also just purchase the internal parts and a new frost plate, then put the meter back together. Both options are cheaper than buying a whole new meter. However, if the meter base breaks instead of the frost plate, this is a defect in the manufacturing process, and we can get a new and free meter from the supplier.

But the bottom line is to try to prevent the meter from freezing in the first place. This can be done by making sure the area around the meter is adequately heated. If this is not possible, then heat tape can be installed on the piping and meter or in conjunction with insulation around the meter.


Low Hanging Fruit for Your Stimulus Basket

Ever since our city first became aware of the possibility of a federal stimulus package focusing on public works, we have been busy as bees finding “shovel-ready” projects to submit for funding. Because I realize efforts like ours are now going on all over the U.S., I thought it might be helpful to post some example projects local governments could submit that require minimal planning and design:

Purchase/produce and replace street signs throughout a community or region – everyone knows the federal government recently passed legislation that requires all of us to upgrade our street signs by a specific date to meet new reflectivity regulations. Although we do have several years in order to comply, this is an expensive and unfunded mandate, so why not use the monies from the stimulus package to purchase or produce and install your signs. This is a relatively easy project to put together for bidding. Local government can even take advantage of existing state joint purchasing programs and bid out only the installation. This idea puts to work all the suppliers and manufacturers who make sign materials as well as the laborers who will install the signs.

Purchase, install, and implement a water leak detection service – Over the last few years, companies have developed leak-detection technology that involves placing a small device on the “city-side” of a customer’s water service lines. The device listens to the sounds in the water mains and reports the possibility of water leaks back to the provider.

Leak Detection Report
Leak Detection Report - Green: No Leak, Red: Leak

Unfortunately for our city (from a funding view), we have already set up a system like this. But for those who have not, they would get started by simply contacting a company that provides this technology to get a proposed price. The actual work involves the set-up of a fixed network and installation of data recorders/transmitters. A leak detection project puts to work those who manufacture/supply the recorders/transmitters, electricians, and plumbers. In addition the end result of this project is the reduction of water loss.

Purchase and install a fixed-network metering project
– while you’re in the process of setting up a fixed network to read your leak detection units, why not think about installing either new meters (if needed) or a metering data collection system that reads meters on a 24/7 basis. Again, little planning and design. Simply contact the metering/fixed network companies and get your pricing in order. Like the leak detection system, this project puts to work the companies that manufacture/supply the units along with employing plumbers to install meters. Plus this system can also help decrease water loss.

The important thing to remember as we up together our lists is that not every worthwhile project has to involve significant engineering or even shovels to put people to work. If anyone has thought of any other easy-to-implement ideas, please post them in a comment and help your fellow, public works brethren. And if you don’t work for local government, think about passing along the ideas to your local officials. Remember in the end, it is about putting people all across America to work and improving our public works assets.