Clog
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VRVs. That's how I found TerryLove online.
Vigorous debate and discussion between Moderator HJ and a member with a longer multi-syllable name that began with C. (forgot full user name as I type this, sorry).
First post here, and I first want to take a moment to thank Terry Love for creating and hosting this bulletin board space to discuss best plumbing practices, and for permitting the comingling of professional and diy'er alike.
Now on to the topic: Vacuum Relief Valves. (VRV) Not required in my jurisdiction. Not indicated for my single story installations where the top fill type hot water heater tank (HWHT) is on the same floor level as all the fixtures it serves. But in the spirit of following best practices in everything I do, I am motivated to build beyond minimal requirements, with installs that are beyond reproach, and that would pass inspection in any community.
There are a number of questions that I was not able to distill answers for from in my reading thus far:
1. If a HWHT would implode from vacuum, why wouldn't a thermal expansion tank? (TET)
2. If a TET would implode from vacuum, does preventing that implosion, and the HWHT implosion, dictate the inline location of, and the relative height of, the VRV vis a vis the TET? It is very clear that the VRV needs to be higher than the HWHT, but does the VRV also need to be higher than the TET, especially if the TET is higher than the HWHT, if the TET is also expected to be protected from implosion?
3. Does it matter if the TET is plumbed inlet down or inlet up, for purposes of preventing implosion, if implosion is indeed even a concern? It is clear that TET plumbing orientation is not a factor in the function of the TET, so this question is solely focused on the protection of the TET from implosion, if that is a risk.
4. In my planned installation, the TET would be plumbed with inlet pointing downward, to promote more circulation of the water that heated expansion pushes into the tank. As the water cools down (relatively speaking) the water in the tank, pushed by the air bladder set to the same psi as the previously measured supply pressure, might be more readily circulated into the system, rather than being encumbered by gravity "trapping" the same stagnant water in the tank if the inlet were pointing upward.
5. However, when considering trapped air, vacuum, and tank implosion, my mind gets clogged. Hence the user name. Further more, it is unclear to me how far the bladder in the TET will distend toward the water inlet in the absence of any water, if the TET were pressurized to 55 psi (the last measured supply pressure). Will the air bladder balloon all the way to the mouth of the inlet, which would overwhelmingly overcome any partial vacuum in the TET from a sudden drainage of water? Or is the bladder limited in excursion, leaving the empty half of the TET where the water was suddenly evacuated from vulnerable to partial collapse?
I think that is enough questions for an inaugural post. Thank you in advance for your help in understanding these issues a little better.
Vigorous debate and discussion between Moderator HJ and a member with a longer multi-syllable name that began with C. (forgot full user name as I type this, sorry).
First post here, and I first want to take a moment to thank Terry Love for creating and hosting this bulletin board space to discuss best plumbing practices, and for permitting the comingling of professional and diy'er alike.
Now on to the topic: Vacuum Relief Valves. (VRV) Not required in my jurisdiction. Not indicated for my single story installations where the top fill type hot water heater tank (HWHT) is on the same floor level as all the fixtures it serves. But in the spirit of following best practices in everything I do, I am motivated to build beyond minimal requirements, with installs that are beyond reproach, and that would pass inspection in any community.
There are a number of questions that I was not able to distill answers for from in my reading thus far:
1. If a HWHT would implode from vacuum, why wouldn't a thermal expansion tank? (TET)
2. If a TET would implode from vacuum, does preventing that implosion, and the HWHT implosion, dictate the inline location of, and the relative height of, the VRV vis a vis the TET? It is very clear that the VRV needs to be higher than the HWHT, but does the VRV also need to be higher than the TET, especially if the TET is higher than the HWHT, if the TET is also expected to be protected from implosion?
3. Does it matter if the TET is plumbed inlet down or inlet up, for purposes of preventing implosion, if implosion is indeed even a concern? It is clear that TET plumbing orientation is not a factor in the function of the TET, so this question is solely focused on the protection of the TET from implosion, if that is a risk.
4. In my planned installation, the TET would be plumbed with inlet pointing downward, to promote more circulation of the water that heated expansion pushes into the tank. As the water cools down (relatively speaking) the water in the tank, pushed by the air bladder set to the same psi as the previously measured supply pressure, might be more readily circulated into the system, rather than being encumbered by gravity "trapping" the same stagnant water in the tank if the inlet were pointing upward.
5. However, when considering trapped air, vacuum, and tank implosion, my mind gets clogged. Hence the user name. Further more, it is unclear to me how far the bladder in the TET will distend toward the water inlet in the absence of any water, if the TET were pressurized to 55 psi (the last measured supply pressure). Will the air bladder balloon all the way to the mouth of the inlet, which would overwhelmingly overcome any partial vacuum in the TET from a sudden drainage of water? Or is the bladder limited in excursion, leaving the empty half of the TET where the water was suddenly evacuated from vulnerable to partial collapse?
I think that is enough questions for an inaugural post. Thank you in advance for your help in understanding these issues a little better.
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