Korean underfloor heating control system (KD Navien boiler, NR-15SB manual)

Almost all Korean houses use an underfloor heating system.
Korean underfloor heating, called “Ondol,” has a history of thousands of years.
Modern Korean houses use a method of circulating water heated by a boiler through PVC pipes buried in the floor of the room.

KD Navien boiler, NR-15SB room controller manual

NR-15SB room controller description

• 난방 : Heating (select heating mode)
• 외출 : Go outside (or Summer mode)
• 온수조절 : Service water temperature adjust

Room heating control

This boiler controller provide 3 modes of room heating.

• 실내("indoor air", run by indoor air temperature) mode : This room controller has indoor air temperature sensor. Once setting desired air temperature, boiler will automatically operate to keep target air temperature. Range: 10 to 40 ℃
• 온돌("floor", run by floor water temperature) mode : Regardless of the indoor air temperature, the temperature of the water circulated from the boiler to the floor of the room is controlled by desired temperature. Range: 40 to 80 ℃
• 예약(Reserved heating) mode : The boiler is forced to operate at regular time intervals regardless of temperature. Not recommended in general condition.

실내 "indoor air" control mode

1. Press the "난방" Heating button repeatedly until "실내" indoor air indicator appears.

When indoor air temperature heating is selected, "실내" indoor air indicator blinks.

2. Press the + or - button to set the desired indoor air temperature.

• When the "실내" indoor sign blinks, press + or - button to set the desired heating temperature between 10 to 40 ℃ and it will be automatically saved. Recommended indoor air temperature in winter by government: 18 to 20 ℃
• The desired temperature is adjusted by 1 ℃.
• If the indoor air temperature is lower than the desired temperature, the status green lamp lights up and the heating is turned on.
• To stop heating, set the desired temperature lower than the current temperature.

온돌 "floor" heating water temperature control mode

1. Press the "난방" Heating button repeatedly until "온돌" floor water temperature control  indicator appears.

When floow water temperature control is selected, "온돌" floor water control indicator blinks.

2. Press the + or - button to set the desired floor water temperature.

• When the “온돌” floor water temperature sign blinks, press the + or - button to set the desired heating water temperature between 40 to 80 ℃ and it will be automatically saved.
• The heating temperature is adjusted by 1 ℃.
• Heating is automatically optimized according to the desired heating temperature, and the operation lamp turns on.
• To stop heating, set the desired temperature lower than the current temperature.

Caution: Do not set the "온돌" floor heating water temperature to a high temperature (above 70 ℃) and use it continuously for a long time. There is a risk of burns.

외출 Going out : Activating and deactivating

This is a mode that runs the boiler at a minimum and only hot water is used without floor heating, or when no one is home in winter season.

You can use it in the summer when you only use hot service water(shower, wash basin and kitchen sink water) without floor heating.

In winter, when leaving the home, press "외출" go outside button. Then "외출" mode activated and blinks on display. Once you return to home, press "외출" go outside button then it will return previous heating mode.

This is more useful during the winter when you don't want your pipes to freeze, but you don't want to keep your heat and waste energy on all day. It will keep it on but it won't keep it at such a high level.

온수조절 Service water temperature adjust
(shower, wash basin and kitchen sink water)

Press the "온수조절" service water temperature adjust button

• When the "온수온도" Service water temperature adjust sign blinks, press + or - button to set the desired temperature between 30 to 60 ℃ and it will be automatically saved.
• The desired temperature is adjusted by 1 ℃.

빠른온수 Quick service water heating

Press the "온수조절" service water temperature adjust button for 2 seconds.

Then "빠른온수" quick service water heating blinks on display.

The quick service water heating function temporarily stops underfloor heating and focuses only on hot service water, automatically turning off after 10 minutes.