If you were Registered and logged in, you could reply and use other advanced thread options
|
Posted by Jeff Wisnia on December 29, 2008, 1:04 pm
I was advised to also replace the vacuum relief valve when I recently
had to replace our home's (leaking) water heater. Since the part was
cheap enough and I'd never thought to replace it in the 23 years (and
two previous water heater replacements by me.) since its original
installation, I went ahead and bought one.
Then I started wondering just what conditions would cause enough
negative pressure to collapse a water heater tank.
*******
The description of Watts' vacuum relief valve reads:
Series N36 Watts Water Service Vacuum Relief Valves are used in water
heater/tank applications to automatically allow air to enter into the
piping system to prevent vacuum conditions that could siphon the water
from the system and damage water heater/tank equipment.
*******
Since our home is at the crest of hill, I suppose that if the city
pumping system went bad, or a water main below us burst there could be a
long enough column of water "hanging down" to pull up to one atmosphere
of vacuum in our home's supply, which is probably more than enough to
collapse a water heater tank.
A plumber I asked said that a fire engine pumping out of a nearby
hydrant could also create a negative pressure in the main.
Are those the expected kind of things a vacuum relief valve protects
against?
Thanks guys, and Happy New Year,
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.
|
|
Posted by trader4 on December 29, 2008, 1:10 pm
show/hide quoted text
> I was advised to also replace the vacuum relief valve when I recently
> had to replace our home's (leaking) water heater. Since the part was
> cheap enough and I'd never thought to replace it in the 23 years (and
> two previous water heater replacements by me.) since its original
> installation, I went ahead and bought one.
> Then I started wondering just what conditions would cause enough
> negative pressure to collapse a water heater tank.
> *******
> The description of Watts' vacuum relief valve reads:
> Series N36 Watts Water Service Vacuum Relief Valves are used in water
> heater/tank applications to automatically allow air to enter into the
> piping system to prevent vacuum conditions that could siphon the water
> from the system and damage water heater/tank equipment.
> *******
> Since our home is at the crest of hill, I suppose that if the city
> pumping system went bad, or a water main below us burst there could be a
> long enough column of water "hanging down" to pull up to one atmosphere
> of vacuum in our home's supply, which is probably more than enough to
> collapse a water heater tank.
> A plumber I asked said that a fire engine pumping out of a nearby
> hydrant could also create a negative pressure in the main.
> Are those the expected kind of things a vacuum relief valve protects
> against?
> Thanks guys, and Happy New Year,
> Jeff
> --
> Jeffry Wisnia
> (W1BSV + Brass Rat '57 EE)
> The speed of light is 1.8*10^12 furlongs per fortnight.
I would guess that the main concern is not siphoning action collapsing
the tank, but it taking enough of the water out so that either the
electric elements then burn out or steam is generated with a gas unit,
exploding the tank. Of course the TPR valve is there to hopefully
prevent the latter.
Here in NJ, I've never seen one used, even in new construction. So,
apparently here they are not required by code. The first time I ever
even saw one on a water heater was on a recent episode of This Old
House, when they were removing a water heater. All in all, unless
I'm missing something, I don't see the need.
|
|
Posted by Jeff Wisnia on December 29, 2008, 1:37 pm
trader4@optonline.net wrote:
show/hide quoted text
>
>>I was advised to also replace the vacuum relief valve when I recently
>>had to replace our home's (leaking) water heater. Since the part was
>>cheap enough and I'd never thought to replace it in the 23 years (and
>>two previous water heater replacements by me.) since its original
>>installation, I went ahead and bought one.
>>Then I started wondering just what conditions would cause enough
>>negative pressure to collapse a water heater tank.
>>*******
>>The description of Watts' vacuum relief valve reads:
>>Series N36 Watts Water Service Vacuum Relief Valves are used in water
>>heater/tank applications to automatically allow air to enter into the
>>piping system to prevent vacuum conditions that could siphon the water
>>from the system and damage water heater/tank equipment.
>>*******
>>Since our home is at the crest of hill, I suppose that if the city
>>pumping system went bad, or a water main below us burst there could be a
>>long enough column of water "hanging down" to pull up to one atmosphere
>>of vacuum in our home's supply, which is probably more than enough to
>>collapse a water heater tank.
>>A plumber I asked said that a fire engine pumping out of a nearby
>>hydrant could also create a negative pressure in the main.
>>Are those the expected kind of things a vacuum relief valve protects
>>against?
>>Thanks guys, and Happy New Year,
>>Jeff
>>--
>>Jeffry Wisnia
>>(W1BSV + Brass Rat '57 EE)
>>The speed of light is 1.8*10^12 furlongs per fortnight.
>
>
>
> I would guess that the main concern is not siphoning action collapsing
> the tank, but it taking enough of the water out so that either the
> electric elements then burn out or steam is generated with a gas unit,
> exploding the tank. Of course the TPR valve is there to hopefully
> prevent the latter.
I hadn't thought of that "overheating" angle, thanks.
I suppose it would require someone to open a hot water faucet and leave
it open long enough for the tank to have enough of its contents sucked
out through the dip tube to cause that kind of problem. Since there's no
telling what sorts of things folks might decide to do, your point sounds
valid to me.
It was also mentioned to me by my plumber aquaintance that present codes
here in Red Sox Nation require power disconnect switches adjacent to new
electric water heater installations for the same reason they've been
used for a long time near outside AC units. They can prevent repair
folks from getting zapped or whacked when someone else decides to flip a
panel breaker back on while they're messing around inside the equipment.
I wonder what's next?
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.
show/hide quoted text
>
> Here in NJ, I've never seen one used, even in new construction. So,
> apparently here they are not required by code. The first time I ever
> even saw one on a water heater was on a recent episode of This Old
> House, when they were removing a water heater. All in all, unless
> I'm missing something, I don't see the need.
|
|
Posted by hallerb@aol.com on December 29, 2008, 4:25 pm
> It was also mentioned to me by my plumber aquaintance that present codes
> here in Red Sox Nation require power disconnect switches adjacent to new
> electric water heater installations for the same reason they've been
> used for a long time near outside AC units. They can prevent repair
> folks from getting zapped or whacked when someone else decides to flip a
> panel breaker back on while they're messing around inside the equipment.
> I wonder what's next?
> Jeff
> --
> Jeffry Wisnia
All new vehicles will come with no tamper GPS receivers. if tye GPS
breaks the vehicle doesnt run.
it checks the speed limit on the road you are on and acting like a
govenor prevents speeding.
in a chase situation where police are chasing a vehicle they send out
a signal, all close by vehicles drop to 5 MPH limit
national tracking of all people begins, technically it already has
with cell phones.
every citizen gets a new national ID card, in exchange for DNA sample,
picture and fingerprints, plus retinal scan.
great for searching out bad guys. making credit card purachase? just
one card will work for any person, with fingerprint scan and id number
charge gets applied to your account. cash is becoming obsolete for
better tracking.
dont laugh its all for our safety
|
|
Posted by mkirsch1 on December 30, 2008, 1:39 pm
show/hide quoted text
> dont laugh its all for our safety
Ha ha ha.
Too bad it will take two people for every one of us to effectively
monitor our activities to the extent that the "big brother is
watching" conspiracy theorists often spout off about.
Soooo, who is paying the salaries of the 600 million "big brothers"
watching the 300 million of us? Where are they hiding 600 million
government employees?
|
Page 1 of 2 1 2 > last >>
| Similar Threads | Posted | | Washing Machine Water Inlet Valves - Cheap Source of Solonoid Control Valves? | January 3, 2007, 7:11 pm |
| What to do with water shutoff valves and water heater when on vacation? | November 19, 2006, 6:38 pm |
| turn water valves on and off on water heater | August 7, 2008, 5:13 pm |
| Hot water tank pressure relief | August 30, 2005, 10:41 am |
| Water heater relief valve -- POW! | December 27, 2005, 12:34 am |
| Water valves - why multiturn? | December 18, 2008, 3:05 pm |
| Replacing valves where the water comes in | December 18, 2008, 4:12 pm |
| Re: pressure relief valve releasing water | May 11, 2006, 2:29 pm |
| water pressure relief valve strainer | September 26, 2006, 3:14 pm |
| 12 or 24 VDC Whole house water shutoff valves | August 26, 2005, 8:31 pm |
|
|
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap
> had to replace our home's (leaking) water heater. Since the part was
> cheap enough and I'd never thought to replace it in the 23 years (and
> two previous water heater replacements by me.) since its original
> installation, I went ahead and bought one.
> Then I started wondering just what conditions would cause enough
> negative pressure to collapse a water heater tank.
> *******
> The description of Watts' vacuum relief valve reads:
> Series N36 Watts Water Service Vacuum Relief Valves are used in water
> heater/tank applications to automatically allow air to enter into the
> piping system to prevent vacuum conditions that could siphon the water
> from the system and damage water heater/tank equipment.
> *******
> Since our home is at the crest of hill, I suppose that if the city
> pumping system went bad, or a water main below us burst there could be a
> long enough column of water "hanging down" to pull up to one atmosphere
> of vacuum in our home's supply, which is probably more than enough to
> collapse a water heater tank.
> A plumber I asked said that a fire engine pumping out of a nearby
> hydrant could also create a negative pressure in the main.
> Are those the expected kind of things a vacuum relief valve protects
> against?
> Thanks guys, and Happy New Year,
> Jeff
> --
> Jeffry Wisnia
> (W1BSV + Brass Rat '57 EE)
> The speed of light is 1.8*10^12 furlongs per fortnight.