Turn it on
- 1Press 전원. The display lights up.
Navien NR-20S in English
Navien's 'on水' six-button controller: 난방 cycles room / floor / timer, + / − sets the number, and 외출 doubles as hot-water-only.
What does each button do?
- 1Model badge · on水on-suBrand badge only. It marks the Navien 'on水' controller line.
- 2Current temperature · 현재온도hyeonjae ondoLabel: the big number is the room temperature now.
- 3Temperature · 온도 숫자ondoShows the temperature in °C (12°C in this photo).
- 4Hot-water pre-heat on · 온수예열onsu yeyeolPre-heat keeps hot water ready in winter. Hold 온수조절 for 2 s to switch it on or off.
- 5Away is on · 외출oechulShown when Away / hot-water-only is on. Heating is off.
- 6Check / fault · 점검jeomgeomThis end of the light bar shows a fault.
- 7Running · 운전unjeonThis end lights when the boiler is running.
- 8Heating mode · 난방 (실내/온돌/예약)nanbang (silnae/ondol/yeyak)Each press moves to the next mode: 실내 (room air), 온돌 (floor), 예약 (timer). Also cancels Away.
- 9Up · +peulleoseuRaises the blinking setting.
- 10Hot-water temperature · 온수조절onsu jojeolPress, then + / − for 30–60°C. Hold 2 s: quick hot water / pre-heat on or off.
- 11Away (hot water only) · 외출 (온수전용)oechul (onsu jeonyong)Stops heating; hot water and frost protection keep working. Press again to return to the previous setting.
- 12Down · −maineoseuLowers the blinking setting.
- 13Power · 전원jeonwonTurns the controller on or off.
What setting should I use?
실내 at 21–23°C, hot water 45°C, pre-heat left on in winter. 외출 only for trips.
How do I…?
Heat the room to a set temperature
- 1If 외출 shows on the screen, press 난방 first.
- 2Press 난방 until 실내 blinks.
- 3While it blinks, press + / − to reach 22. It saves by itself.
Use floor (ondol) mode
- 1Press 난방 until 온돌 blinks.
- 2Press + / − to set the floor-water temperature (30–60°C or 40–80°C, depending on the boiler). Start around 50°C.
Leave for a few days
- 1Press 외출 (온수전용). 외출 appears.
- 2To return, press it again or press 난방.
Run on a timer
- 1Press 난방 until 예약 blinks.
- 2Press + / − to set the pause in hours between heating runs (0–12).
- 3The run length is fixed by the boiler.
Hot water only (summer)
- 1Press 외출 (온수전용). On this model, hot-water-only and Away are the same mode.
Change the hot-water temperature
- 1Press 온수조절. 온수온도 blinks.
- 2Press + / − to set 30–60°C. 45°C is a good shower temperature.
- 3Navien oil boilers use 저 → 중 → 고 steps instead: press 온수조절 again to step.
Turn it off
- 1Press 전원.
- 2In winter use 외출 instead, so the pipes stay protected.
What do the words on the screen mean?
| 현재온도 | Current temperature | The room temperature now. |
|---|---|---|
| 희망온도 | Target temperature | The temperature you set. |
| 실내 / 온돌 / 예약 | Room / Floor / Timer | The active heating mode. |
| 외출 | Away | No heating; hot water and frost protection only. |
| 온수예열 | Hot-water pre-heat | Pre-heat is on (only on some condensing boilers). |
| 빠른온수 | Quick hot water | Quick hot water is on; it ends after 10 minutes. |
| 온수온도 | Hot-water temperature | Blinks while you set hot water. |
| 운전 / 점검 | Running / Check | Light bar: running = boiler working, check = fault. |
What trips people up on this model?
- If the screen shows 외출, the heating is off. In photo 37 the room is only 12°C for this reason. Press 난방 to heat again.
- Holding 온수조절 for 2 s toggles pre-heat or quick hot water. A short press only sets the temperature.
- Set hot water above 50°C only with all taps closed, as the manual says.
It shows an error. Now what?
A fault lights the 점검 end of the light bar. Note any code on the display and call 1588-1144.
Service line (Korean): 1588-1144