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* Damage can occur from frozen water within the device and pipes even in warm environments.
Be sure to read below for appropriate measures.
* Repairs for damage caused by freezing are not covered by the warranty.
Freezing cannot be prevented when the power plug is unplugged. Do not remove the power
plug from the wall outlet.
Freezing will be prevented regardless of whether the operation switch is ON or OFF.
Take the measures below for extremely cold temperatures*. <Only using the remote controller>
Outside temperature including wind chill factor less than -30°F (-35°C) for NRC711-DV, NRC661A-DV
or -4°F (-20°C) for NRC711-OD, NRC661A-OD.
- For models NRC711-DV, NRC661A-DV, when supplying combustion air from the indoors, the room
temperature must be greater than 32°F (0°C) to prevent freezing and the room inside must not have
negative pressure.
This method can protect not only the heater, but also the water supply, water piping and mixing valves.
1. Turn off the Power On/Off Button.
2. Close the gas supply valve.
3. Open a hot water fixture, and keep a small stream of hot water
running. (0.1 gallon (400cc)/minute or about 0.2" (4mm) thick.)
* If there is a mixing valve, set it to the highest level.
4. The flow may become unstable from time to time.
Check the flow 30 minutes later.
* In general, it is not advisable to run water through the unit when
it is OFF
(
page 6), but in this case freeze prevention is more important.
* Remember to set mixing valves and fixtures to their original levels before using the unit again
to prevent scalding.
* If there is still a risk that the unit will freeze, drain the unit as shown on the next page.
Preventing Damage from Freezing-1
Freezing is prevented within the device automatically by the freeze-prevention heater.
If water will not flow because it is frozen
1. Close the gas and water valves.
2. Turn off the power button.
3. Open the water supply valve from time to time to check whether water is running.
4.
When the water is flowing again, check for water leaks from the unit and piping before using.
If the heater or the piping is frozen, do not use the heater or it may get damaged.
CAUTION
* In normal operation, freezing is prevented within the device automatically unless the outside
temperature without wind is below -30°F (-35°C) for NRC711-DV, NRC661A-DV or -4°F (-20°C) for
NRC711-OD, NRC661A-OD.
- For models NRC711-DV, NRC661A-DV, when supplying combustion air from the indoors, the
room temperature must be greater than 32°F (0°C) to prevent freezing and the room inside
must not have negative pressure.
* 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.
If there remains a freezing risk, contact the nearest Noritz agent.
0.2" (4mm)
thick
Hot Water Fixture
