NSS Installation and Setup Procedures 5

Question 1

What is the maximum vent length for a Navien NPE-240A2 using 4-inch PVC pipe in a two-pipe direct vent configuration?

Accepted Answer

75 equivalent feet

Answer

The NPE-240A2 allows up to 75 equivalent feet of 4-inch vent piping in a two-pipe direct vent configuration.

Question 2

When connecting a Navien unit to a recirculation loop using the built-in pump, which setting controls the recirculation temperature differential?

Accepted Answer

The ΔT parameter in the service menu

Answer

The ΔT (delta-T) parameter in the Navien service menu sets the temperature differential at which the recirculation pump activates.

Question 3

Which Navien installation step is required when the unit is installed where the gas supply line contains significant moisture or debris?

Accepted Answer

Install a sediment trap and drip leg upstream of the unit's gas inlet

Answer

A sediment trap and drip leg must be installed upstream of the gas inlet to prevent moisture and debris from entering the gas valve.

Question 4

During initial startup of a Navien unit, the installer notices error code 003E. What does this indicate?

Accepted Answer

Ignition failure after three attempts

Answer

Error code 003E on Navien units indicates ignition failure after the unit has attempted ignition multiple times without confirming a flame.

Question 5

What is the function of the 'flow sensor' in a Navien tankless water heater during the installation and commissioning phase?

Accepted Answer

Detects water flow to trigger unit activation and measure GPM

Answer

The flow sensor detects when water is flowing through the unit and measures GPM to trigger activation and modulate burner output.

(NSS) Certified Navien Service Specialists Practice Test