Navien NPE240-A2 NaviCirc Confusion

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JSS00

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For whatever reason, Navien has conflicting information all over the place regarding the proper installation of the comfortflow/navicirc system.

Do I still need to hook up the cold to the recirc port with a check valve above the tee if I am using an A2? The technical drawing from the NPE-A2 webpage (under pdf, not CAD) makes it seem like they don’t require it anymore, but I can’t be sure based on conflicting information on their website.

I believe the documentation for the navicirc tee is still from the NPE-A series and not updated for the A2.

However, the comfortflow/navicirc webpage specifically says A2 yet still shows a tee on the cold side connected to the recirc port. Is this simply a marketing mistake and they changed the text to A2 but no one changed the illustration?

If the technical drawing is the correct method, what purpose does the check valve on the cold main serve? Do I need a check valve considering it’s shown on the technical drawing but not in the actual NPE-A2 install manual.

Also unrelated but what is the point of the hot button system? Doesn’t It defeat the purpose of the recirc system if I have to hit a button?

Another unrelated question if anyone knows the answer, how does this system know to turn the pump on when the navicirc tee opens? Is it constantly running even when the tee is closed? Wouldn’t this burn out the pump? Or does it only push a little bit of pressure and can sense resistance and goes full power when it detects a drop in resistance? Or does it only turn on intermittently in short intervals?

One last question: what does the smart setting on external recirculation do?

These guys make a great product but they really need to step their game on on documentation and easy information access.

Thank you to anyone who can help.
 

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John Gayewski

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There are people more familiar with Navien here, but external vs internal recirculation are different piping.

Check valve on the cold keeps hot water from being pushed into the cold when you draw cold water only from a tap.

They claim you can dead head their pumps, but I don't think it's great. Better to add a dedicated recirc.

Smart setting I think times the pump to run based on when it's run before or maybe temperature, not sure.

We installed some naviens in a school with a long recirc. It was like 1400ft of 1/2". The pump inside of a Navien can't pump that far at speed. We had to use external recirculation and a different pump.
 
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John Gayewski

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You could probably go to any manufacturers web site or instruction manual and find all different configurations for all different applications. It's not really a matter of them providing confusing info, but knowing how to sort it is what differentiates a plumber or professional vs a person in a different field. Plumbers spend a lot of time ciphering schematics and drawings and interpreting specs. Probably why Navien and other manufacturers don't deal with homeowners over the phone and void warranties.
 

JSS00

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You could probably go to any manufacturers web site or instruction manual and find all different configurations for all different applications. It's not really a matter of them providing confusing info, but knowing how to sort it is what differentiates a plumber or professional vs a person in a different field. Plumbers spend a lot of time ciphering schematics and drawings and interpreting specs. Probably why Navien and other manufacturers don't deal with homeowners over the phone and void warranties.
Sorry I think there’s some misunderstanding. I do know about the difference in piping and internal and external recirc. I have installed NPE-A systems where you pipe the cold into the return with a tee and a check valve on the cold side to prevent looping.

With the new A2 systems it appears this has changed but there is a lot of conflicting information on their website. I have looked through their website, documentation, and even technical drawing. If you browse through my pictures you’ll see one from the navicirc page, one from the navicirc tee documentation (which has not been updated for A2), one from the A2 install manual, and one from the A2 technical drawing off the A2 document page. Not one of these pages show the same thing.

Regarding your theory on the check valve, this wouldn’t make sense as the recirc pump is pumping into the faucets regardless of the check valve in their schematic.

I will probably follow the technical drawing that shows the check valve on the street side. I can’t think of a reason to have a check valve on the street side like they show. Im just trying to get some clarification on a few things. Don’t want to do anything that hurts the unit or voids the warranty.

If you check my pictures you’ll see what I’m rambling about.

Also I’m just doing a small house so the runs are within the parameters they specify.
 
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breplum

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The newish NPE A2 do not require special piping like the old NPE A, if only the Navcirc is used.
There are setup clicks to follow on the display.
They definitely want the added check valve on the cold as displayed in your image number one. And that also then calls for an expansion tank or those mini exp devices for tankless applications.
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JSS00

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The newish NPE A2 do not require special piping like the old NPE A, if only the Navcirc is used.
There are setup clicks to follow on the display.
They definitely want the added check valve on the cold as displayed in your image number one. And that also then calls for an expansion tank or those mini exp devices for tankless applications. View attachment 85384
Okay, that’s what I was leaning towards. Do you know what purpose a check valve on the main serves?
 
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