Navien A2 model settings that affect recirculation time

[coolgreany]

I recently had a Navien NPE-180A2 installed together with the Navicirc valve under a bathroom sink. I have the temp set at 121 degrees Fahrenheit.

I tried the intelligent mode circulation for a few weeks but that didn't seem to improve the availability for hot water for routine morning showers (normally take showers around the same time every morning).

So, I decided to try the hot button method. Instead of buying the standard hard-wired button, I tried this small relay to simulate the button action.

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I wired the relay button wires up to "Signal 2" terminals on the pre-installed hot button module and did not add any temperature sensor to the terminals with the pre-installed cross strap.

I added the relay to Google Home and it turns on the pump on command at a 1 GPM rate. From what I have read in other threads, the pump should stay on for 5 minutes (default setting - verified in the advanced menu).

I've tested it with various settings but can't get the system to circulate for more than 2.5 minutes. That's close and I only wait about 30 seconds now for the shower to start flowing warm/hot water. Three minutes of circulation time should be about perfect.

Our water lines are in the slab and it's only about 55 ft as the crow flies from the tank to the sink valve so should be well under the hundred feet requirement. See the attached screenshot to see the various settings I've tried.

I'm just trying to understand what might be causing the recirc pump to shut down before the set run time (4 minutes). If I could squeak out 3 minutes that should work. Most settings are on page 93 of the A2 Manual Version: 1.0 (Feb. 2021))

What else can I try to get the pump to run for 3 minutes?

 

[coolgreany]

Anyone? I've tried multiple setting variations but I'm beginning to think that the Navien recirc valve is closing when a certain temperature is reached regardless of the pump Menu settings. I can live with that but would like to understand exactly "what" is causing the pump to shut down at 2.5 minutes regardless of unit menu settings..

 

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[Breplum]

Sorry...just don't know...as a plumber I'd call tech support...but, they dislike talking to homeowners.

 

[coolgreany]

Sorry...just don't know...as a plumber I'd call tech support...but, they dislike talking to homeowners.

Thanks. Yes, I've read that here and in other forums which is why I was asking here. After a few more days of test data, I'm thinking the Navicir manifold may be causing the system to top circulation perhaps due to a temperature sensor in the Navicirc. It looks like 2.5 minutes is the most I can get with my configuration.

"To prevent too much hot water from flowing into the cold water line, the NaviCirc includes a feature that automatically blocks circulation when reaching a temperature of approximately 95°F (35°C)."