Rheem RTGH Owners Manual

52
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.
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 "Water Supply Installation".
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.
Plumbing
INSTALLATION INSTRUCTIONS
Water Supply (cont.)
Relief
Valve
Union
Union
Cold Water Supply
Shut-O Valve
Cold Water
Supply Inlet
Hot Water
Supply Outlet
Relief Valve
Discharge Line
Pressure
Relief Valve
Pressure
Relief Valve
Cold Water
Service Valve
Cold Water
Service Valve
Water
Inlet
Water
Inlet
Water
Outlet
Water
Outlet
Hot Water
Service Valve
Hot Water
Service Valve
Drain
Drain
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.