mdk0420
Well-Known Member
Hello! New to the forums and new to plumbing! So naturally I have a couple of questions that even all of my research couldn't get an answer on.
Here is a rough diagram of my project (Although there have been a few slight changes). I'm using a Navien 180 NCB-E. Its not perfect by any means and its not up to plumbing diagram standards but it should be easy enough to understand and the city has accepted it as my blue print for my permit.
I think it should look pretty good. If you have any suggestions please let me know. Some of the changes I made include:
Lowest drain valve on return line will be a wye strainer with a drain valve hooked up to it
Shut off valve after circulator pump will also have a purge valve
Right before the expansion tank will be a "Drain Valve" that will actually act as a fill valve for adding inhibitor
There will be a shut off valve on the main cold/DHW supply lines
That is all the changes I've come up with so far. Here is a question for the guru's though:
My older style expansion tank is corroded and I'm replacing it with a simple 4.4 gallon amtrol tank (https://www.supplyhouse.com/Amtrol-141363-THERM-X-SPAN-T-12-Expansion-Tank-4-4-Gallon-Volume)
How should I go about this for purging purposes? The tank has a 3/4" MNPT end. The taco 4900 air separator has a 1/2" FNPT end. I was thinking of using a closed 1/2" nipple with a 3/4" x 1/2" bushing and then a coupling to connect the tank. Should I also add in an isolation valve and purge valve to be able to do maintenance on it, or should the shut off valve after the tank, the shut off valve at the start of the supply line, and the drain valve be good enough to purge the tank each year? These tanks don't come with a drain valve like my old one did so there doesn't seem to be any good way to completely drain these.
Also any suggestions on where to put check valves throughout the system? Thanks!
Here is a rough diagram of my project (Although there have been a few slight changes). I'm using a Navien 180 NCB-E. Its not perfect by any means and its not up to plumbing diagram standards but it should be easy enough to understand and the city has accepted it as my blue print for my permit.
I think it should look pretty good. If you have any suggestions please let me know. Some of the changes I made include:
Lowest drain valve on return line will be a wye strainer with a drain valve hooked up to it
Shut off valve after circulator pump will also have a purge valve
Right before the expansion tank will be a "Drain Valve" that will actually act as a fill valve for adding inhibitor
There will be a shut off valve on the main cold/DHW supply lines
That is all the changes I've come up with so far. Here is a question for the guru's though:
My older style expansion tank is corroded and I'm replacing it with a simple 4.4 gallon amtrol tank (https://www.supplyhouse.com/Amtrol-141363-THERM-X-SPAN-T-12-Expansion-Tank-4-4-Gallon-Volume)
How should I go about this for purging purposes? The tank has a 3/4" MNPT end. The taco 4900 air separator has a 1/2" FNPT end. I was thinking of using a closed 1/2" nipple with a 3/4" x 1/2" bushing and then a coupling to connect the tank. Should I also add in an isolation valve and purge valve to be able to do maintenance on it, or should the shut off valve after the tank, the shut off valve at the start of the supply line, and the drain valve be good enough to purge the tank each year? These tanks don't come with a drain valve like my old one did so there doesn't seem to be any good way to completely drain these.
Also any suggestions on where to put check valves throughout the system? Thanks!
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