NSS Combustion and Venting Systems 2

Question 1

Which Navien error code typically indicates a blocked flue or exhaust condition?

Accepted Answer

E048

Answer

Navien error code E048 indicates an exhaust blockage, causing the unit to shut down automatically to prevent combustion gases from backing up into the living space.

Question 2

What type of sealant must be used to join PVC vent pipes in a Navien installation?

Accepted Answer

Listed PVC primer and solvent cement

Answer

Listed PVC primer and solvent cement creates a permanent, chemically bonded, airtight joint required for Category IV positive-pressure vent systems.

Question 3

What is the primary function of the condensate trap on a Navien condensing unit?

Accepted Answer

Maintain a water seal to prevent flue gas from escaping through the drain

Answer

The condensate trap maintains a water seal that prevents flue gases from escaping into the occupied space through the condensate drain line, similar to how a plumbing P-trap works.

Question 4

What is the minimum clearance required between a Navien horizontal vent termination and the ground or anticipated snow level?

Accepted Answer

12 inches

Answer

A minimum of 12 inches above grade or anticipated snow level is required to prevent vent blockage from debris, standing water, or seasonal snow accumulation.

Question 5

What is the maximum equivalent vent length typically permitted for a Navien NPE series unit using 2-inch PVC pipe?

Accepted Answer

60 feet

Answer

Most Navien NPE series units allow a maximum of 60 equivalent feet of 2-inch vent pipe; upgrading to 3-inch pipe extends the allowable run to approximately 100 equivalent feet.

(NSS) Certified Navien Service Specialists Practice Test

(NSS) Certified Navien Service Specialists Practice Test

NSS Combustion and Venting Systems 2