NSS Installation and Setup Procedures 3

Question 1

What is the correct pipe size for the cold water inlet on a Navien NPE-240A2 tankless water heater?

Accepted Answer

3/4 inch NPT

Answer

The NPE-240A2 requires 3/4-inch NPT connections for both the cold water inlet and hot water outlet.

Question 2

When installing Navien's NFC series combi-boiler, what is the purpose of the buffer tank connection?

Accepted Answer

To provide hydraulic separation and prevent short-cycling of the boiler

Answer

A buffer tank provides hydraulic separation and sufficient water volume to prevent short-cycling of the combi-boiler.

Question 3

Which DIP switch setting on a Navien NPE series unit enables the 'comfort flow' recirculation mode?

Accepted Answer

DIP switch 3, position ON

Answer

DIP switch 3 in the ON position activates the built-in comfort flow (recirculation) feature on NPE series units.

Question 4

During outdoor installation of a Navien tankless unit, what is the minimum ambient temperature rating for the unit's operation?

Accepted Answer

-4°F (-20°C)

Answer

Navien outdoor units are rated for ambient temperatures as low as -4°F (-20°C) with the built-in freeze protection active.

Question 5

What action must be taken if the incoming gas pressure to a Navien unit is below the minimum required 3.5 inches W.C.?

Accepted Answer

Contact the gas utility to resolve the supply pressure issue before startup

Answer

If supply pressure is below 3.5 inches W.C., the gas utility must correct the pressure before the unit is commissioned.

(NSS) Certified Navien Service Specialists Practice Test