By Barry Stone
Dear Barry,
Last month, the gas company charged us nearly $500, up from $39 the previous month. We had all the gas fixtures checked by a contractor and he found no problems. But when the gas company came out, they said the problem was a leaking TPR valve on the water heater. Can you please explain what a TPR valve is and how is could cause our gas bill to skyrocket like this?
--Melissa
Dear Melissa,
The gas company's claim makes very little sense. There is no logical relationship between gas leaks and TPR valves.
TPR stands for "temperature pressure relief." The purpose of a temperature pressure relief valve is to release steam and hot water when a water heater becomes too hot. These valves have been standard equipment on water heaters since the mid-1960s. Prior to that time, excessive heat and pressure could cause a water heater to explode. TPR valves are simply there to release the pressure - to prevent loss of life and destruction of property.
When a TPR valves leaks, all that is expelled is hot water and steam, not gas! Furthermore, if your TPR valve were leaking, you would see the hot water at the end of the discharge pipe. If you don't see leaking water, either the valve is not leaking or the end of the pipe is not in a visible location. For example, the end of the pipe could be under the house (a prohibited location, by the way).
The gas company might argue that a leaking TPR valve could cause the burner to work overtime in order to heat the cold water that comes in as the hot water leaks out. But the volume of cold water that would require $460 worth of gas would probably fill a swimming pool, and a leak of that magnitude would certainly be apparent somewhere.
Whomever you spoke to at the gas company is apparently in need of an entry-level course in water heater anatomy. If the gas company is unwilling to reconsider the cause of your increased bill, you can report them to the regulatory agency that governs utility companies in your area.
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