Measuring Inlet Gas Pressure - Navien CR-180 Installation Manual

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Measuring Inlet Gas Pressure:

The Navien water heater cannot operate properly without sufficient inlet gas
pressure and volume. Below are instructions on how to check the inlet gas
pressure.
THIS IS ONLY TO BE DONE BY A LICENSED PROFESSIONAL
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 3.0" and 10.5'' WC for Natural gas
between 8.0" to 13.5" WC for Liquid Propane.
8. The maximum inlet gas pressure must not exceed the value specified by the
manufacturer and that the minimum value listed is for the purposes of input
adjustment.
pressure test port on gas line
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