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9. Preventing Damage form Freezing-1
Preventing Damage form Freezing
Chapter 3. – Unit Operation
CAUTION
• Damage can occur from freezing 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.
2. It is possible to prevent freezing by selecting a ‘Recirculation Mode’.
1. Two modes for freeze protection.
1-1. Recirculation Pump mode.
• When water temperature falls between 42°F(5.5°C) and 46°F(8°C), the circulation pump starts operating for freeze protection.
• Mixing valve maintains open for internal water circulation.
• The cycle will restart at the approximate time interval (operate for 10 min and stops for 30 sec) and and it will stop if the water
temperature goes above 50°F(10°C).
1-2. Burner Combustion mode.
• When water temperature drops below 41°F (5°C) it will start minimum combustion with internal water circulation.
• When water temperature goes above 104°F (40°C) it will stop.
• After combustion mode is stopped, the pump will continue for 3 minutes..
• If the water heater is turned on for recirculation mode, pre-heating mode, or hot water use mode, the freeze protection mode will
automatically stop.
• With the recirculation operation set, hot water will be automatically circulated in the hot water pipes.
• If the recirculation piping is installed, you can select the external recirculation mode, the water heater will
prevent the external plumbing to the unit from freezing.
• If there is still a risk that the unit will freeze, drain the unit as shown on page 32.
If water does not ow 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 owing again, check for water leaks from the equipment and piping before using.
If the heater or the piping is frozen, do not use the heater or it may get damaged.
Electrical power, gas, water and the main switch must be on. If any of the above items are not connected properly,
then water must be drained including the condensation trap and unit unplugged from electrical power.
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