[Shop-talk] Water Pressure Relief Valve

[David Scheidt]

neglected to cc the list...


On Sat, Sep 14, 2013 at 10:10 AM, David Scheidt <dmscheidt at gmail.com> wrote:

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>
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> On Fri, Sep 13, 2013 at 8:18 PM, Doug Braun <doug at dougbraun.com> wrote:
>
>> If this is a city water system, wouldn't the expanding water simply back
>> up
>> into the supply lines?
>>
>>
> Code -- and good sanitation -- should require an anti-backflow valve on
> the input.  Water heaters run at less than 140 are potential breeding
> grounds for all sorts of the things you do not want in your water, like
> legonella.  It's becoming common for code to require storage water heaters
> to have a temperature of 140F or higher, and use tempering valves to keep
> faucets from scalding people.  (If you can, you do want to feed your
> dishwasher and washing machine with hot hot water.)
>
>
>
>> If it is a well system, shouldn't there already be an expansion tank that
>> can deal with it?
>> If there is an expansion tank, perhaps it has lost its air supply and is
>> completely full of
>> water? ( I'm not really familiar with the details of maintaining a well
>> system...)
>>
>>
> There should be some soft of expansion system, yes.  House may be old
> enough that the expansion system was the city water supply --no backflow
> preventor, and one has been installed.  It might also be that there's an
> anti-hammer riser that was sized (usually too small...) to do it, and it's
> full of water, not air.
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>
-- 
David Scheidt
dmscheidt at gmail.com