Measuring Gas Pressure - Navien NR-180(A) Operation & Installation Manual

Measuring Inlet Gas Pressure:
Procedure to measure the inlet gas pressure:
1. Shut off the manual gas valve on the supply gas line.
2. Open a hot faucet. The unit should turn on and the gas in the
gas pipe line should purge. Leave the faucet on to keep the unit
running until the unit shuts down due to lack of gas supply.
Then shut off the hot faucet.
3. Remove the screw for the pressure port located on the gas
inlet of the Water Heater.
4 Connect a manometer to the pressure port and reset it to
zero.
5. Re-open the manual gas valve. Check to see that there are
no gas leaks.
6. Open multiple fixtures that have high flow rates (bathtub, showers, kitchen sink) to
ramp the Water Heater up to its maximum burn.
7. When the Navien Water Heater is at maximum burn, check the inlet gas pressure
reading on the manometer; it should read between 5.0" and 10.5" WC for
Natural gas between 8.0"(9.0") to 13.5" WC for Liquid Propane.
8. The maximum inlet gas pressure must not exceed the value specified by the
manufacturer and the minimum value listed is for the purposes of input adjustment.
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Pressure test port on gas line