Measuring The Inlet Gas Pressure - Navien NCB-150E Service Manual

4.2 Measuring the Inlet Gas Pressure

WARNING
The boiler cannot function properly without sufficient inlet
gas pressure. Measuring the inlet gas pressure should be
performed by a licensed professional only.
The inlet gas pressure must be maintained between 3.5" and
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10.5" WC for natural gas and between 8.0" and 13.5" WC for
liquefied propane.
The appliance and its individual shutoff valve must be
●
disconnected from the gas supply piping system during any
pressure testing of that system at test pressures in excess of
1/2 psi (3.5 kPa).
The appliance must be isolated from the gas supply piping
●
system by closing its individual manual shutoff valve during
any pressure testing of the gas supply piping system at test
pressures equal to or less than 1/2 psi (3.5 kPa).
22 NCB-E Service Manual
To measure the inlet gas pressure:
1. Shut off the manual gas valve on the gas supply line.
Gas Valve
2. Open a hot water faucet. The boiler should turn on and the gas
in the gas supply line will be purged.
3. Leave the faucet on until the boiler shuts down due to a lack of
gas supply, and then turn off the hot water faucet.
4. Unclasp the 3 buckles that fix the cover to the boiler, and then
remove the cover by lifting it and pulling it outward.
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CAUTION
Ensure that no cables are in the way before folding down the
PCB assembly. If the assembly is stuck, do not force it. Doing
so may damage the cables and result in serious malfunctions.
Check again to ensure that no cables or any other parts are in
the way before you proceed.
Opened Closed
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Version 1.4