Dual NPE-240A Settings

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New Member
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Los Angeles
I own a large home and the builder installed dual (2) Navian NPE-240A units in a cascade configuration. The proper communiction cable was done correctly. The hoseu plumbing has a recirculation line. All is working just fine. In both units the valve is set to External and the DIP settings is OFF, ON, OFF. Is this the correct setting when cascading 2 units?

2nd question is my gas usuage to run the recirculation system is about 1 Therm per day and current rates are about $3/Therm; about $100/month. I know this becuase when not a home my gas usuage is 1 Therm/day. I changed the setting on both units to Intelligent Preheating but turning ON DIP Switch-1. Maybe I need to give the system more time figure out my usage but it now takes about 4-5 minutes to get hot water. The house has 5 bathroom and is 5,000 sq ft. The NPE-240A are located on an exterior wall (again, Iive in Southern California). Seems like my gas usuage is down but my water usage is up.


Licensed plumbing contractor
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San Francisco Bay Area
In the A series, the cascade settings are not dip switch related.
Don't you have an installation manual?
In the 10 switch panel, switches 1-3 only relate to Recirculation and your reported settings are correct for ext. recirc.
The way to save money and have on demand hot water is the Hotbutton setup at all the sources. The "builder" was an idiot if that wasn't done. I thought it was required by T-24 that user initiated recirc was the law.
It does take up to two weeks for intelligent preheating to learn.
Hey, wait a minute.

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