Gas Supply Pressures and Testing
Commercial and residential gas water heaters and boilers are designed and certified to operate within a specified inlet gas supply pressure range. It is important to ensure the gas supply remains within the specified pressure range during operation and system leakage testing. To identify the maximum and minimum inlet gas pressures, refer to the labeling on the appliance and gas control/valve. Exposing the appliance and gas control/valve to gas pressures that exceed specified values can result in improper operation and potential damage to the appliance and its components. Refer to the Use and Care Manual for proper installation, operation and maintenance.
Example of Appliance Rating Plate
UPC-A Bar Code: [Placeholder]
Serial Number: XXXXX12345
Model Number: NC
Type Gas: Natural
Input BTUH: [Value not fully specified in OCR]
Gas Pressure (In. W.C.): Manifold: 4.0, Max. Inlet: 10.5, Min. Inlet: 5.0
Certifications: ANSI Z21.10.1, CSA 4.1-(XXXX), Category 1 Natural Draft
Maximum Working Pressure: 150 PSI
Country of Origin: Mexico
Assembly Location: Mexico
Patents: US. Patents 6,482,575; 6,862,165; 6,701,874; 6,358,875; 7,252,502; 7,537,265; 7,435,081; 8,322,312 and pending.
Clearances: Minimum clearances from combustible or noncombustible construction specified.
Manufacturer: Rheem Sales Company, Inc. Water Heating Division Montgomery, Alabama 36117 USA
Serial Number Bar Code: [Placeholder]
Example of Gas Control Label
Identifier: WVXXXXXXXX
Gas Type: NAT GAS ONLY
Outlet Pressure: 5.0" WC OUTLET
Max Inlet Pressure: 1/2 PSI MAX INLET
Certifications: C, SP, US
Gas pressure testing should follow the requirements in the national, state and local codes, and the appliance's Use and Care Manual.
Important Safety Notes for Pressure Testing:
- 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).
Service Action Required in the Event of Over-Pressurization
If an appliance has been subjected to inlet gas supply pressure(s) above the specified value(s), the gas control/valve MUST be replaced. The entire appliance, including the burner assembly and gas connections, must be thoroughly inspected by a qualified service technician. In some cases, full unit replacement may be necessary, as determined by the technician. Suspicion of exposure to excessive inlet gas pressure requires following the above directions.
Before installing a new gas control/valve or appliance and returning it to service, the source of excessive pressure must be identified and corrected by a qualified service technician. Verify that the system pressure is less than ½ psi (3.5 kPa).
Warning: Improper installation, adjustment, alteration, service, or maintenance can cause property damage, personal injury, or death. Installation and service must be performed by a qualified installer, service agency, or the gas supplier. Refer to the Use and Care manual.
Limited Warranty coverage is specific to manufacturing defects only. Adverse installation site conditions, such as over-pressurization of appliances, are excluded from coverage.
