Navien CR-180 Installation Manual page 18

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Pressure Relief Valve:
� An approved %", maximum 150 psi pressure relief valve must be installed on the
hot water outlet, as close to the unit as possible. Please see below for more
information on approved pressure relief valves;
� Each Navien water heater has a high-temperature shut off switch built in as a
standard safety feature (called a temperature high limit switch) therefore a
"pressure only" relief valve is required. This unit does not come with a pressure
relief valve but one must be installed on the hot water outlet;
� The discharge capacity of the pressure relief valve must be at least equal to the
maximum pressure rating of the water heater;
� The maximum input BTUH rating on the valve must be equal to or greater than the
maximum input BTUH rating of the water heater. For example, if installing a Navien
CR-210 at 175,000 BTUH, the pressure relief valve must have a maximum input
rating of not less than 175,000 BTUH;
The discharge piping for the pressure relief valve must be directed so that the hot
�
water cannot splash on anyone or on nearby equipment. Attach the discharge tube
to the pressure relief valve and run the end of the tube to within 6" from the floor.
This discharge tube must allow free and complete drainage without any restrictions;
No reducing coupling or other restriction may be installed in the discharge line.
The following %", maximum 150 psi valves are examples of valves approved for use
�
with all Navien products:
1. Wilkins P-1 OOOA (Zurn Industries)
2. Conbraco 17-402-04
3. Watts Industries 3L(M7)
4. Cash Acme FWL-2 %"
Instructions for pressure, temperature and vacuum relief valves shall specify that no
valve is to be placed between the relief valve and the tank. The instructions shall specify
installation in such a manner that the discharge from temperature and pressure relief
valves will be conducted to a suitable place for disposal when relief occurs and that no
reducing coupling or other restriction be installed in the discharge line.
Pressure Rel ief Valve
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Union
Pressure
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Shutoff
Valve