pressure variation in water heater


  #1  
Old 12-07-05, 02:06 PM
ljeyrich
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pressure variation in water heater

Lately my tpr valve has been leaking some on my water heater. I bought a pressure reader and here's what happens: The pressure incoming to the house is about 80 psi just above the regulator (which looks kind of old). I drained the hot water from the hot water heater and then hooked up the pressure meter. It started at about 60 psi but very slowly worked its way up to 150-160 at which time the valve leaked (I guess the valves actually work!) Then I tried running the bathroom faucet for 2 seconds on cold. The pressure on the water heater instantly dropped to like 65 psi then slowly worked its way back up. I think I need some type of tank type thing - is this right? Also, is it difficult to install or should a plumber do it? Thanks.

Lewis
 
  #2  
Old 12-07-05, 07:00 PM
majakdragon's Avatar
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I think you are referring to an expansion tank. It does sound like you need one. Not difficult to install. Ask for instructions where you purchase it. Or, Post back and we can try to help you. Good luck.
 
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Old 12-14-05, 08:04 PM
sehenry2000
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majakdragon, I don't understand what the expansion tank does. Is it a wide spot in the line (tank) that has vapor on top? How did this fellow reach 150 psig, the regulator from his water well is bad (not controlling)? Something had to pump the pressure that high unless he turned the water to steam.
 
  #4  
Old 12-15-05, 08:49 AM
ljeyrich
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just as an update, I figured out that my incoming pressure is not really the problem, I was reading the gauge at the wrong time - the incoming pressure is actually around 50-60 psi. But the pressure in the entire system slowly goes up after closing a faucet, etc presumably because the water heater is heating the water, which increases the pressure because of the fact that there is a check valve type thing at my water inlet which doesn't allow water or pressure to siddipate back out to the water line.
 
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Old 12-15-05, 09:31 AM
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sehenry2000,
An expansion tank when placed in the cold water supply line just before the water heater provides an additional space in the system to accommodate the increased volume of water created by thermal expansion, returning it to the system when hot water delivery is demanded. In other words it gives the expanded water some place to go other than the floor via the TPR valve.

ljeyrich,
Replace the TPR valve to be sure it is functioning correctly as they do wear out over time. They are very inexpensive (under $10)
 
 

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