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Supply water piping
• Do not use PVC, iron, or any piping which has been
treated with chromates, boiler seal or other chemicals.
• Mount a check valve and a shut off valve (near the inlet).
• In order for the client to use the water heater
comfortably, 98.1 to 491 kPa (14 to 70 psi) of
pressure is needed from the water supply.
Be sure to check the water pressure. If the
water pressure is low, the water heater cannot
perform to its full capability, and may become a
source of trouble for the client.
Drain piping
• Expansion water may drop from the pressure
prevention device and wet the floor. If neces
-
sary, provide drain piping or use a drain hose
to remove the water.
Hot water piping
• Do not use lead, PVC, iron or any piping which
has been treated with chromates, boiler seal or
other chemicals.
• The longer the piping, the greater the heat loss.
Try to make the piping as short as possible.
• Use mixing valves with low water resistance.
Use shower heads with low pressure loss.
• If necessary, use a pump or other means to en-
sure that the supply water pressure to the inlet
of the heater does not fall below 29 psi when the
maximum amount of water is being demanded.
Also install a pressure meter on the inlet. If this
is not done, local boiling will occur inside the
water heater causing abnormal sounds and de-
creasing the durability of the heat exchanger.
Freeze Prevention
• For model series NR66 and NR71, freezing is prevented within the device automatically unless the
outside temperature without wind is below -30°F (indoor installation) or -4°F (outdoor installation).
• For model series NR50, freeze prevention heaters are not included with the water heater from the
factory. If this model is installed in an area where the outside temperature can approach freezing
conditions (32°F or below), then the optional freeze prevention kit must be used. For temporary
freeze protection measures, refer to the Owner's Guide.
• The freeze prevention heaters will not prevent the plumbing external to the unit from freezing.
Protect this plumbing with insulation, heat tape or electric heaters, solenoids, or pipe covers.
• In order for the freeze prevention heaters to operate, the water heater must have power at all times.
