Turn it on
- 1Press 전원 (bottom right). The screen lights up.
Navien NR-25S in English
A white Navien controller with an orange screen and one round jog wheel: press the label you want around the wheel, then turn the wheel to set the number.
What does each button do?
- 1Running / check light · 운전/점검unjeon/jeomgeomStatus light: shows the boiler is running, or flags a fault.
- 2Heating mode shown · 난방 실내nanbang silnaeShows the current heating mode (실내 = room air; 온돌 = floor).
- 3Heating target · 난방 희망온도nanbang huimang ondoThe heating temperature you set (23°C here).
- 4Hot water · 온수onsuMarks the hot-water side of the screen.
- 5Hot-water target · 온수 희망온도onsu huimang ondoThe hot-water temperature you set (40°C here).
- 6Heating power: Low · 난방세기 약nanbang segi yakCurrent heating power level: 약 (low), 중 (medium) or 강 (high).
- 7Heating mode · 난방 (실내/온돌)nanbang (silnae/ondol)Press repeatedly to switch between 실내 (room air) and 온돌 (floor).
- 8Timer · 예약yeyakSets 'every __ hours, run __ minutes'.
- 9Hot-water temperature · 온수 (온도조절)onsu (ondo jojeol)Press, then turn the wheel for 30–60°C. Hold 2 s for quick hot water (10 min).
- 10Heating power · 난방세기nanbang segiPress, then turn the wheel to 약 / 중 / 강 to set how hard the boiler heats.
- 11Jog wheel · 다이얼daieolTurn it to change the blinking value. Settings save by themselves after a moment.
- 12Hot water only · 온수전용onsu jeonyongNo heating, hot water only. Pick a heating mode to undo.
- 13Away · 외출oechulStops heating while you are out; hot water and frost protection keep working. Press again to return to the previous setting.
- 14Power · 전원jeonwonOn / off. Off stops heating and hot water.
What setting should I use?
실내 at 21–23°C, 난방세기 중, hot water 45°C. In a cold room with poor insulation, 난방세기 강.
How do I…?
Heat the room to a set temperature
- 1Press 난방 (top left) until 실내 shows.
- 2Turn the wheel to 22.
- 3Wait a moment. It saves by itself.
Use floor (ondol) mode
- 1Press 난방 until 온돌 shows.
- 2Turn the wheel to about 50 (range 30–65°C; some units 40–83°C).
Leave for a few days
- 1Press 외출 (bottom left).
- 2To come back, press 외출 again. The previous setting returns.
Run on a timer
- 1Press 예약 (top). The screen shows '○○시간마다 ○○분 가동'.
- 2Turn the wheel to choose every how many hours (1–24).
- 3Press 예약 again. The minutes blink.
- 4Turn the wheel to choose run minutes (10–50, in 10-min steps), then press 예약 to finish. Example: every 3 h, run 30 min.
Hot water only (summer)
- 1Press 온수전용 (right).
- 2To heat again, press 난방 and choose a mode.
Change the hot-water temperature
- 1Press 온수 (top right). The hot-water 희망온도 lights up.
- 2Turn the wheel to 45. It saves by itself.
Turn it off
- 1Press 전원.
- 2In winter use 외출 instead, so the pipes stay protected.
What do the words on the screen mean?
| 난방 실내 / 온돌 | Heating: room / floor | Active heating mode. |
|---|---|---|
| 희망온도 | Target temperature | The temperature you set (left = heating, right = hot water). |
| 난방세기 약 / 중 / 강 | Heating power low / medium / high | How hard the boiler heats: its maximum output, not the temperature. |
| ○○시간마다 ○○분 가동 | Every __ h, run __ min | Timer setting. |
| 빠른온수 | Quick hot water | Quick hot water is on; it ends after 10 min. |
| 온수전용 | Hot water only | Heating is off. |
| 운전/점검 | Running / Check | Status light at the top right. |
What trips people up on this model?
- 난방세기 (약/중/강) is heating power, not temperature. 약 can make a big cold room warm up very slowly.
- There is no + / −. Everything is set by turning the wheel after pressing a label.
- To stop heating without 외출, set the target below the current room temperature.
It shows an error. Now what?
Faults show on the 운전/점검 light at the top right. Note any code on the screen and call 1588-1144.
Service line (Korean): 1588-1144
