Navien NPE-240A and NaviCirc Installation Question

[Pmd5700]

Hello,

I just had my Navien NPE-240A (EDIT: It's actually an NPE-240A2) and NaviCirc installed today. First time tankless user. I was reviewing the manual and installation after they left, and I don't think they have the NaviCirc hooked up properly, and I want to confirm before I call them back out here.

1) They have the internal valve set to "Internal Recirculation".
2) The mode in the settings is set to "Internal Recirculation".
3) I think, even if the settings were correct, that I would need a check valve in the cold water supply line after the tee.

I have no problem adjusting the settings and internal valve, but I think I would rather have them install the check valve if it's required. I just want to make sure I'm not overlooking something here and that there is a check valve installed (internally or externally).

Thank you.

 

[Fitter30]

Look at page 21 install manual there is a two way valve that needs to be turned for internal recirculation they didn't need the piping external.

 

[Sponsor]

 

[Bannerman]

NaviCirc requires External circulation mode for both the DIP switch settings and the 2-way valve.

Because the bridge pipe is bridging both the supply and recirculation return connections, a check-valve is required above the T on the supply line to prevent the pump from pushing water backwards through the supply line connection to the circulation return connection in a small circulation loop.

 

[Pmd5700]

Look at page 21 install manual there is a two way valve that needs to be turned for internal recirculation they didn't need the piping external.

In my copy of the manual, Page 21 has the gas hookup.

NaviCirc requires External circulation mode for both the DIP switch settings and the 2-way valve.

Because the bridge pipe is bridging both the supply and recirculation return connections, a check-valve is required above the T on the supply line to prevent the pump from pushing water backwards through the supply line connection to the circulation return connection in a small circulation loop.

The manual shows changing the valve from INT to EXT and changing the setting via the keypad. No mention of the dip switches.

 

[Bannerman]

The appropriate settings for NPE-240A External Recirculation are as the diagram below.

The manual page you posted pertains to NPE-240A2 in which case, the DIP switch adjustements have been replaced with settings adjustments performed on the front digital panel.

The diagram below is from the NaviCirc manual. The check valve is required to correctly utilize Navicirc, regardless of whether the Hot Button option will be installed or not. The solinoid valve shown on the circulation return line is optional.

 

[Dlinsley]

In my copy of the manual, Page 21 has the gas hookup

Do you have an A2 then? My A2 and Navicirc were installed a couple of weeks ago, and the installer configured it as per page 34 (nothing connected to the recirc inlet, which is new for A2 unless the diagram is wrong, but it is working well here and the installer is listed as a Navien Service Specialist on Navien's site) with the Int-Ext valve set to Ext and the menu set to External recirc.

 

[Bannerman]

The A2 manual shows the internal circulation pump is situated in a much different location than in the prior A models. The A2 pump location will now allow return flow to be drawn through either the Recirculation Supply connection or the Domestic Water Supply connection. Compare below.

The name of this thread vs the Manual page pmd5700 posted, makes it uncertain if his unit is an original NPE-240A, or an NPE-240A2 model.

NPE-240A Recirculation Flow path:

Link to page 28 of Navien NPE-240A2 manual:

https://www.manualslib.com/manual/2131563/Navien-Npe-180a2.html?page=28#manual

 

[Pmd5700]

The A2 manual shows the internal circulation pump is situated in a much different location than in the prior A models. The A2 pump location will now allow return flow to be drawn through either the Recirculation Supply connection or the Domestic Water Supply connection. Compare below.

The name of this thread vs the Manual page pmd5700 posted, makes it uncertain if his unit is an original NPE-240A, or an NPE-240A2 model.

Apologies, I do have the A2. I'm still a little confused though. Do I need to set the valve and mode to External Recirculation or Internal? I have the valve going into the Recirculation Port closed and both valve and setting set to Internal and the NaviCirc does not appear to be working.

 

[Bannerman]

You require External circulation.

With the 2-way valve set to internal, the pump will be drawing water through the heat exchanger > buffer tank > check valve and back through the heat exchanger in a small loop.

Placing the 2-way to External, will cause the pump to draw from the home's recirculation loop including the NaviCirc valve.

I understand the digital setting for External mode will cause the pump to operate longer and at a higher flow rate each cycle.

 

[Pmd5700]

Thanks again! So if I understand it right, for my NPE-240A2, I need to set the internal valve to Ext. and the mode to External Recirculation. Then, as long as it's plumbed up like my sketch below, it should work?

 

[Dlinsley]

Thanks again! So if I understand it right, for my NPE-240A2, I need to set the internal valve to Ext. and the mode to External Recirculation. Then, as long as it's plumbed up like my sketch below, it should work?

That is how mine is configured, with External Pump set to No.

 

[Pmd5700]

That is how mine is configured, with External Pump set to No.

So valve to Ext. but setting to Internal Recirculation? And it works as intended?

EDIT: I re-read your post and see you said External Pump to No. I assume then that the valve and A2 internal setting are both set to External Recirculation.

 

[Dlinsley]

So valve to Ext. but setting to Internal Recirculation? And it works as intended?

EDIT: I re-read your post and see you said External Pump to No. I assume then that the valve and A2 internal setting are both set to External Recirculation.

Sorry, yes that is correct. Value set to External. Recirculation set to External, but No to External pump (so that the internal pump is used). In my case I then have Hot Button set instead of Always / Intelligent / Weekly (Schedule). I'll be documenting my Hot Button automation soon.

 

[Pmd5700]

Sorry, yes that is correct. Value set to External. Recirculation set to External, but No to External pump (so that the internal pump is used). In my case I then have Hot Button set instead of Always / Intelligent / Weekly (Schedule). I'll be documenting my Hot Button automation soon.

Ok, that makes sense - and I think I proved it's working now - kind of. I realized that they installed a Grundfos Comfort Valve instead of the NaviCirc. I don't think the Grundfos valve allows for enough flow. I can see the unit kick on the flow only goes to around 0.5gpm then it shuts off shortly after. I'm guessing it's shutting off due to the low flow.

I suppose this is a new issue/question now. Does anyone have any info on these Grundfos valves? I can't really find much online about them. I found one review that said they only operate at around 0.2 gpm...

 

[Rudy_rdz1986]

NaviCirc requires External circulation mode for both the DIP switch settings and the 2-way valve.

Because the bridge pipe is bridging both the supply and recirculation return connections, a check-valve is required above the T on the supply line to prevent the pump from pushing water backwards through the supply line connection to the circulation return connection in a small circulation loop.

Hello . I bought a Taco hot link valve model HLV-1 and wondering if this crossover tee would do the work ?

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[Bannerman]

Taco hot link valve model HLV-1 and wondering if this crossover tee would do the work ?

The Taco HLV-1, Grundfos Comfort Valve and Navien NaviCirc are all crossover valves to allow cold water piping to be used as a hot water return in home's not equipped with a dedicated hot water circulation return loop. While each brand may utilize a thermostatic valve that is calibrated with a different shut-off setting from the others, they all function similarly.

While a DHW circulation system utilizing a cross-over valve can greatly reduce the time for hot water to arrive at distant fixtures, the initial temperature at each faucet will not be as hot compared to a DHW circulation system that utilizes a dedicated return line. To prevent the water in the cold piping from becoming too hot, each of the cross-over valves will stop circulation flow when the temperature of the water arriving at the X-over valve is approx 100 degrees F, give or take a few degrees depending on the valve brand.

 

[Rudy_rdz1986]

Thanks for your help ! I was just wondering if this brand would do the work vs a navicirc brand . Do I have to change setting in any parameters ? Ex 12,14,17 ??

 

[Tholkien]

Hate to bring this up...especially if I'm wrong! But the water lines look like Wirsbo/Uponor that has been painted. Uponor can't be installed outside, as it deteriorates from uv exposure! Eventually it'll start leaking. I may be wrong on waht material it is, but it looks a lot like Wirsbo/Uponor.

As for the internal valve.... If you use the pump for any kind of recirculation, other than inside the heater (to prevent freezing), the valve should be moved from the 9 o'clock position, to six o'clock. You have the updated AT series, so you have no duo switches to worry about It's all in the program. Just follow the manual, and set it to external (for all recirc lines and navicirc tees).

But for your own sake, make sure that isn't Wirsbo/Uponor piping

 

[BenT123]

This thread have confused me at first so to help future readers, A and A2 models differ on water supply hookups. A2 models no longer require cold water supply bypass. Both should be set to External for NaviCirc to work.

page 38, https://www.navieninc.com/downloads/navicirc-installation-and-operation-manual-en