NSS Installation and Setup Procedures 2 — Questions and Answers
Question 1: What is the minimum required clearance above a Navien tankless water heater for service access?
- 6 inches
- 12 inches
- 18 inches (Correct answer)
- 24 inches
Correct answer: 18 inches
Navien requires a minimum of 18 inches of clearance above the unit to allow proper service and maintenance access.
Question 2: When installing a Navien NR or NRC series unit, which gas valve setting must be confirmed before startup?
- Gas type (natural gas or propane) is set correctly on the gas valve (Correct answer)
- The gas valve is fully closed
- The gas valve bypass is engaged
- The gas valve pressure is set to maximum
Correct answer: Gas type (natural gas or propane) is set correctly on the gas valve
The gas type selector on the valve must match the supply gas (NG or LP) before startup to ensure proper combustion.
Question 3: Which type of venting material is approved for use with Navien condensing tankless water heaters?
- Type B double-wall vent pipe
- Schedule 40 PVC or CPVC (Correct answer)
- Single-wall galvanized steel
- Type A stainless steel liner
Correct answer: Schedule 40 PVC or CPVC
Navien condensing units produce low-temperature flue gases and require PVC or CPVC venting rated for the application.
Question 4: During a Navien unit installation, the recirculation pump is wired to which terminal block?
- CNH connector
- CIRC terminals on the PCB (Correct answer)
- COM terminals on the PCB
- The external pump is not wired to the unit
Correct answer: CIRC terminals on the PCB
The internal or external recirculation pump connects to the CIRC terminals on the Navien PCB for integrated control.
Question 5: What is the maximum allowable gas supply pressure for a Navien natural gas tankless water heater at the unit's inlet?
- 3.5 inches W.C.
- 7 inches W.C.
- 10.5 inches W.C. (Correct answer)
- 14 inches W.C.
Correct answer: 10.5 inches W.C.
Navien natural gas units have a maximum inlet gas pressure of 10.5 inches W.C.; exceeding this can damage the gas valve.
Question 6: Which Navien installation step ensures proper condensate drainage from a condensing water heater?
- Connect condensate line to the cold water inlet
- Route the condensate drain to an approved indirect waste with a P-trap (Correct answer)
- Plug the condensate port if the building has no floor drain
- Drain condensate directly into the gas line chase
Correct answer: Route the condensate drain to an approved indirect waste with a P-trap
Condensate must drain to an approved indirect waste receptor with a P-trap to prevent sewer gases from entering.
Question 7: When setting the cascade system ID on multiple Navien units, what is the maximum number of units that can be linked in a single cascade?
- 4 units
- 8 units (Correct answer)
- 16 units
- 32 units
Correct answer: 8 units
Navien cascade systems support up to 8 units linked together using the built-in cascade communication protocol.
NSS Installation and Setup Procedures 2
What is the minimum required clearance above a Navien tankless water heater for service access?