On Sat, 05 Mar 2005 00:13:31 GMT, "Joseph Meehan"
wrote:

David Starr wrote:
I've got a 4 year old 40 gallon gas water heater. Every now & then,
the T&P valve opens and 3 or 4 gallons drain out. The temp isn't set
too high - 1 on a 1-3 scale - so I don't think it's getting too hot.
It seems to happen when I'm using a fair amount of hot water for a
long period of time.. I have a home darkroom & sometimes need water
at 75 degrees for a couple hours; this is when I notice it happening.

Would it be a good idea to replace the T&P valve, or what? Do these
valves deteriorate over time? The valve appears to be doing what it's
supposed to, but I can't figure out why it's happening. Our previous
water heater never did this.




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Dave Starr, Senior Shop Rat Emeritus: 14,647 days in a GM plant.
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I was not going to reply since Jim and Jeff covered the answer very
well, but I have to congratulate you for giving such a accurate and complete
description including observations few people would notice. You made it
easy to identify the problem. Expansion tank it is. (defective or none
existent)


Thanks to all for the help. I'll have to look into an expansion tank.


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Dave Starr, Senior Shop Rat Emeritus: 14,647 days in a GM plant.
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