Rheem RTGH-95XLP-2 Use And Care Manual page 50

INSTALLATION INSTRUCTIONS
Water Piping Arrangement With Service Valve Kit
Service valve kits can attach to all tankless water
heater systems. All kits include two full-port isolation
valves to be used in the COLD and HOT water lines.
When installed, these valves allow one person full
diagnostic testing and ease of flushing the system.
Contact your distributor or place of purchase for
availability and installation information.
Water Supply (cont.)
Relief Valve
A new pressure-relief valve, complying with the
Standard for Relief Valves and Automatic Gas Shut-Off
Devices for Hot Water Supply Systems, ANSI Z21.22/
CSA 4.4, must be installed at the HOT water outlet
connection of the water heater during installation. Local
codes shall govern the installation of any relief valve.
NOTICE:
• The following drawing illustrates a pressure-only relief
valve. If local codes require a combination temperature
and pressure-relief valve, you may need to install an
extension piece to ensure that the valve probe is not
directly in the flow path of the water.
• A pressure relief valve supplied with this water heater must
be installed as shown below.
• Manual operation of relief valves should be performed at
least once a year.
• If the relief valve on the system discharges periodically, a
problem exists. Turn off the water heater, unplug the unit,
and call for service.
One end of the relief valve discharge line connects to
the HOT water outlet pipe as shown above. The other
end of the pipe should be routed to a suitable drain to
eliminate potential water damage.
Relief
Valve
Union Union
Hot Water
Supply Outlet
50
Pressure Pressure
Relief Valve Relief Valve
For safe operation of the water heater, be sure that:
The pressure rating of the relief valve must not exceed
150 psi (1,034 kPa) or the maximum working pressure
of the water heater. (See the rating plate on the water
heater.)
The BTUH rating of the relief valve must equal or
exceed the BTUH input of the water heater. (See the
rating plate on the water heater.)
No valve of any type should be installed between the
relief valve and the water heater.
Discharge from the relief valve should be piped to
a suitable drain. Piping used should be of a type
approved for the distribution of hot water.
HOT and COLD water lines should be insulated up to
the water heater. See page 51.
The discharge line must be NO SMALLER than the
outlet of the relief valve. The drain line must pitch
downward to allow for complete drainage of the line
and the valve.
The end of the discharge line should not be threaded or
concealed and should be protected from freezing. No
valve of any type, restriction, or reducer coupling should
be installed in the discharge line.
Cold Water Supply
Shut-O Valve
Cold Water
Supply Inlet
Relief Valve
Discharge Line
Hot Water Hot Water
Service Valve Service Valve
Water
Water
Outlet Outlet
Drain
Drain
Cold Water Cold Water
Service Valve Service Valve
Water Water
Inlet Inlet