Use and Care Manual

TANKLESS WATER HEATER
Figure 24 – Pressure Drop through the Heat Exchanger
E. PRESSURE RELIEF VALVE
An external pressure relief valve must be installed on this water heater. When installing, observe the following
guidelines. Failure to comply with these guidelines can result in substantial property damage, personal injury, or
death.
This water heater must be provided with an approved 150 psi, ¾” ASME HV Valve that must be installed on
the DHW outlet line (See Figure 30).The 150 psi Pressure Relief Valve must be installed on the DHW supply
line to ensure a compliant installation and safe operation.
This water heater has a high-temperature shut-off switch built in as a standard safety feature. Therefore, a
“pressure only” relief valve is required. DO NOT operate this water heater before the supplied pressure
relief valve is installed with sufficient relieving capacity in accordance with the ASME rating plate on the water
heater.
Pressure relief valves must be installed as close to the water heater as possible. No other valves should be
placed between the pressure relief valve and the appliance. DO NOT install a relief valve with a pressure rat-
ing greater than 150 psi. This is the maximum allowable relief valve setting for this water heater.
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