How To Use Korean Floor Heating & Hot Water System - IVisitKorea
Korean Floor Heating System

How to Use Korean Floor Heating & Hot Water System – Updated 2022

Traditional Korean Floor Heating System – Ondol

Korean houses are heated by an underfloor heating system because most Koreans lived on the room floor without tables and chairs. This type of heating system is quite common in Korea and it’s called ondol, 온돌. When you light a fire in the furnace called Agungi (아궁이) in the kitchen with wood, the hot steam heats the floor of the room next to it. Housewives used Aguni to cook food as well.

Ondol (By Dzihi, CC BY 3.0, httpscommons.wikimedia.orgwindex.phpcurid=8746117)
[ Ondol – By Dzihi, CC BY 3.0 ]

Recent Korean Floor Heating System

Koreans developed and improved the Ondol system to the current Korean floor heating system (Koreans commonly call it Boiler). The system uses city gas (LNG) or oil as fuel rather than wood and is also used to heat the house and provide hot water to the kitchen and bathroom. Usually, normal houses in town use the city gas.

Many visitors to Korea make the mistake of turning on the air-conditioner when they arrive at the house to warm up. But in Korea, generally, an air-conditioner in the apartment is only used for cooling during the summer which means it has no heating function. Therefore, please don’t turn on the air-conditioner in the winter season.

The Basic Structure of the Recent Korean Floor Heating System

Korean Floor Heating System Structure
[ Korean Floor Heating System Structure ]

There are four main pipes under the body of the floor heating system. Left two pipes and valves are used to heat the floor of the house. Coldwater from outside through the water meter is supplied to the system through the rightmost pipe, and hot water for the bathroom and kitchen comes out through the second pipe from the right side.

As you see in the upper image, it uses hot water to heat the floor. And it is possible because the pipes that hot water travels are installed under the floor. I didn’t describe it, but there is a gas pipe (usually yellow) as well.

How To Detect Faults & Causes in Underfloor Heating

  1. Most of all, if there’s any issues with the heating or hot water (Basic checklist).
    • Check the wall controller settings and if it has an error code
    • If there’s an error code, find the code in the system manual
    • Check the power plug of the main heating system body is plugged well
    • Check the gas and distributor valves are open
  2. I only have cold water not hot water.
    • After the basic checks,
    • Check the cold water valve is open (See the upper image)
    • If it’s cold outside, the water inlet could be frozen (See how to thawing pipes below)
      • Remove insulation materials and thaw two pipes, hot water and cold water pipes on the right side, together with a dryer or heater
      • You can wrap two pipes with towels and pouring warm water (Under 60 degrees celsius)
  3. I don’t have both hot and cold water.
    • After the basic checks,
    • Check if there’s is any water supply issue in your neighborhood
    • If it’s not the problem of water shortage and it’s cold outside, the water supply pipe can be likely frozen. The area near the water meter is most likely to freeze because it’s exposed to the outside. Contact a nearby plumber.

How To Prevent Pipes from Freezing

Prevention is better than cure as always. To prevent frozen pipes;

  • Don’t turn off the heating system when you go outside (Set it to “Leave” at least)
  • Keep main body’s pipes insulated by the right-size pipe insulation foam
  • Open the hot water faucet slightly and run water during nighttime or when you are outside

How To Use Korean Floor Heating & Hot Water System

When you stay in a Korean house, you may find a little controller(thermostat) on the wall. By turning it on, you could get hot water or floor heating(or both). The problem is there are dozens of temperature controller manufacturers in Korea, and all controllers are written in Korean. It might be so confusing as foreigners can’t speak or read Korean. I hope this post can help you keep warm during your stay in Korea.

Please, check the name of the manufacturer first and click the proper links below. Even if the controller is not the same as the one in your house, it will work similarly. Let me show you how to use the Korean floor heating and hot water system.

Rinnai Boiler (린나이 보일러)

Indoor Thermostat Type 1. RBMC-43

Rinnai floor heating controller RBMC-43
  1. Power (전원): Turn On/Off (Reset)
  2. Display: Temperature
  3. Hot water (온수): Select to provide a large amount of hot water for bath and shower. Temperature: Low (저) Mid (중) High (고)
  4. Heating (난방): Heating temperature wheel. Low (저) / High (고)
  5. Leave Function (외출): To make the heating system to a low temperature.
  6. Heating Off (꺼짐): To turn off the heating (usually in the summer we use this).
  7. Schedule (예약): Schedules the time to start and stop the boiler.
  8. Room temperature-heating (실온) / Floor-heating (온돌): Choose which one you want to set.

Indoor Thermostat Type 2. RBMC-12

Rinnai floor heating controller RBMC-12
  1. Power(전원): Turn On/Off (Reset)
  2. LED Operation Indicator (운전): Turns on while the boiler is operating.
  3. Only Hot water (온수전용): Select to provide hot water only (no floor heating /used usually in the summer).
  4. Hot water & Floor Heating (난방온수): Select to provide both hot water and floor heating (in winter).
  5. Leave Function (외출): To make the heating system to a low temperature.
  6. Heating (난방수온도조절): Floor heating temperature wheel.
  7. Water temperature (온수온도조절): Low (저온) High (고온).

Indoor Thermostat Type 3. RBMC-28

Rinnai Floor Heating Controller RBMC-28
  1. Hot water (온수): Select to provide hot water (in summer and winter).
  2. Water temperature (온수온도): Low – Mid – High
  3. Floor Heating (난방): Floor heating operated (only in winter).
  4. Floor heating temperature (난방온도): Low (저온) High (고온).
  5. LED Operation Indicator (연소): The boiler burner is ON.
  6. Leave Function (외출): To make the heating system to a low temperature.
  7. Schedule (예약): Schedules the time to start and stop the boiler.
Rinnai floor heating controller functions RBMC-28


Kiturami Boiler (귀뚜라미 보일러)

Indoor Thermostat (CTR-5700)

Kiturami Boiler Controller CTR-5700

1. Display: Displays status such as Current Function (현재온도), Target Temperature (희망온도), Scheduled Start/Stop Time (예약), Burning (운전), and Season (계절).
2. Function: Sets Room (실내), Schedule (예약) and Leave function (외출). > To operate floor heating make a status on 실내(Set Room temperature) mode.
3. Bath (목욕): Select to provide a large amount of hot water for bath and shower.
4. Power (전원): Turn On/Off (Reset)
5. LED Operation Indicator: Turns on while the boiler is operating.
6. Up/Down (올림/내림): Increases or decreases the target value of a specific function.
7. Season (계절선택): Sets heating temperature (Spring:봄, Summer:여름, Autumn:가을, Beginning of Winter:초겨울, Winter: 겨울) or schedules start/stop time.
8. Schedule (예약설정): Schedules the time to start and stop boiler.

Indoor Thermostat (CTR-8000)

Kiturami CTR-8000 Thermostat Manual

1. Display: Displays status such as Current Function (현재온도), Target Temperature (희망온도), Scheduled Start/Stop Time (예약), Burning (운전), and Season (계절).
2. Bath (목욕): Select to provide a large amount of hot water for bath and shower.
3. Setting (설정): To configure the floor heating and hot water temperatures
4. Select (선택): Select the setting menu
5. LED Operation Indicator: Turns on while the boiler is operating.
6-7. Up/Down (올림/내림): Increases or decreases the target value or the temperature
8. Power (전원): Turn On/Off (Reset)

To use indoor heating

1. Click 4. 선택 (Select)
2. Choose the setting mode you want to change. When you click “선택 (Select), the setting mode changes, 실내 (Indoor) – 예약 (Reservation) – 외출 (Leave), one by one.
3. If you selected the setting mode, change the target temperature (희망온도) using Up / Down buttons.
4. Click 4. 선택 (Select) or it will be applied if you just leave it.

To use hot water

1. Click 3. 설정 (Setting). Then the hot water display bar starts to flash.
2. Set the target hot water temperature using Up / Down buttons.
3. Click 4. 선택 (Select) or it will be applied if you just leave it.

Indoor Thermostat Type 1. NR-10E

Navien Floor heating system controller NR-10E
  1. Power(전원): Turn On/Off (Reset)
  2. LED Operation Indicator(운전): Turns on while the boiler is operating.
  3. Floor Heating Temperature Wheel(난방조절): Floor heating operated / Low(-) High(+).
  4. Leave Function(외출): Select to make heating system to a low temperature.
  5. Heating Off(꺼짐): Select to turn off the heating (usually we use this in the summer).
  6. Room temperature-heating(실내): Activate room temperature-heating (in winter).
  7. Only Hot water(온수전용): Select to provide hot water only (No floor heating/used in summer).
  8. Floor-heating(온돌): Activate floor-heating (in winter/similar function with 실내).
  9. Schedule(예약): Schedules the time to start and stop boiler.
  10. Water temperature(온수조절): Low(저) Mid(중) High(고).

Indoor Thermostat Type 2. FR-5

Gyeongdong Navien Controller FR-5
  1. Power(전원): Turn On/Off (Reset)
  2. Display: Displays status such as Room-temperature(실내온도), Water Temperature(난방수온도), Burning(운전).
  3. Only Hot water(온수전용): Select to provide hot water only (no floor heating/in summer).
  4. Floor Heating Temperature Wheel(실내조절): From 10 to 40 degrees.
  5. Leave Function(외출): Select to make the heating system to a low temperature.
  6. Water temperature(난방수온도): Summer(여름 ), Spring/Autumn(봄/가을), Winter(겨울).

These control box samples will help you turn on the heated floor and hot water while you are experiencing the freezing cold weather in South Korea. Let us know if you run into any problems. While you are experiencing the different types of heating systems in Korea, also check out “Things to do in Korea in Winter,” to plan out your winter trip. Korea is surrounded by mountains so it’s the perfect place to go ski and snowboard. Here are the Best Ski Resorts in Korea. If you do not have time to go skiing, check out the winter festivals in Korea as well. It is the perfect place to experience the holidays in another country.

Let us know if you have any questions. We are here to help!


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25 thoughts on “How to Use Korean Floor Heating & Hot Water System – Updated 2022”

    1. Hello Henrique,

      Unfortunately, I could only find the Korean version manual.
      I will send ST and DX-type Korean manuals to your email address.
      Sorry but that’s the best at the moment.

      Best,
      Jay

  1. I had a question about your experience with humidity and floor heating. Someone posted some advice about using floor heating in conjunction with the AC to lower the humidity in the house. What is your take on that? To me it sounds like you are just wasting energy and that by using the floor heat it will only add to the humidity not lessen it. Thoughts?

    1. Hi Candace,

      Thank you for reading the article and reaching out to us. First, I should make it clear that I’m not a professional heating system engineer.
      We just wanted to help visitors to Korea can use the Korean floor heating system well as we have used Korean floor heating systems for a long time.
      Personally, I agree with your opinion that turning on the AC and floor heating system at the same time is a waste of energy.
      AC itself dehumidifies and there is a dehumidification mode as well.

      Thanks again.
      Jay

  2. Xin chào. Tại sao máy nước nóng của tôi bật lên không có nước nóng, xong còn trở về chế độ 확인 và 0,3 và nước không nóng.

    1. Hi Tien,

      I’m sorry I can’t speak Vietnamese.
      This is the Google translation of your words and it’s hard to understand the situation.
      If you let me know the controller’s model number, I will try to find the manual.

      Best,
      Jay

    2. Tiến ơi. Sửa dc chưa. Tôi cũng bị lỗi giống bạn. Hãy chỉ tôi cách sửa nhé

  3. Please help. Im cold… haha. I left my shower on all night with heat on. And today my shower is working just fine by my floor heating, which was on too, isnt. It makes a grinding sound and turns off. I turned my shower back on and that is working but floor isnt

    1. Hi Megan,

      There could be many reasons. Are all rooms cold? Do you think it’s not working at all or works but it’s not hot like before?
      If it’s very cold outside, the circulation pipe might be frozen. If there’s no heat on the floor at all, you may have to check the three-way valve with an engineer. If you think there’s heat but it’s not warm as before, you may have to drain air from the pipes.
      Please, check it with a nearby engineer. Happy New Year and hope it works again.

      Best regards,
      Jay

  4. I have Navien FR-5 heating system. It takes more time to heat up. Like 3/4 hours to go temperature from 17 to 19. How can I reduce the heating time? And if I keep power button turn on and select leave option, is not that increase gas bill?

    1. Hi Rakhi,

      If it takes 3 to 4 hours to heat up the room temperature from 17 to 19, I recommend you to get an inspection from a plumber. It’s not a normal condition.
      And about the appropriate temperatures when you sleep or away from home, please take a look at the article from the Department of Energy. https://www.energy.gov/energysaver/thermostats

      Best regards,
      Jay

  5. Hi, I recently moved into a small one-room and am not used to the heating system. Do I need to have the heating on at all times to prevent the pipes from freezing? Will I be charged as much as normal heating if I put it on 외출? I was aware that the heating cost is high so I have not been using the heater much. Thank you so much for your blog it is really informative.

    1. Hi Hanamam,

      Thank you for reading our blog post.
      When you leave the house for over several hours, make it to “Leave (외출)”.
      Leave feature avoids pipe freezing and you can heat up the room temperature quickly when you get back home.
      I hope it helps you to stay warm.

      Kind regards,
      Jay

  6. I have one general question. Is there a need to keep the boiler ON for both water heating and floor heating throughout the day during winters ?

  7. Hi. Asking for some help due to my kiturami ctr 5700 plus has no power by now as in literally no display . But before the power totally gone i ‘ve used it …like there is a strange noise from the pipe everytime i used to and open the water… I am badly needing hot water especially now …winter is coming …Please ..please needing your assistance. Looking forward hearing from you .
    Thank you very much ..Be Blessed…

    1. Hi Jha,

      Even I’m not a floor heating system engineer, I searched for the answer to your problem because I thought there might be more information in Korea than yours.
      This is the best post in Korean I found. Please, use the Google Translation to read it and let me know if you need any more help.
      https://blog.naver.com/janocan/221703888001
      Hope you fix the problem soon.

      Best regards,
      Jay

  8. Hi. Just wanna ask how to set my kiturami ctr-5700 plus boiler when leaving my house to avoid the pipes being frozen during winter season? And what is the ideal winter degree temperature enable to activate this?

    1. Hi Leonardo,

      Thank you for reaching out. When you set the controller to “외출(Leave)”, it maintains the temperature to 8 degrees Celsius to avoid pipe freezing.
      But when you come back home, you might feel cold and it will take some time to heat up. I only use “외출(Leave)” feature, when I leave the house for a couple of days.
      I hope it can be an answer to your question.

      Warm regards,
      Jay

  9. Heat Pumps Porirua

    This is a really great content, I can see how detailed you have gone through and explained about how to use Korean floor heating system. I love this article, thanks for producing such great contents. I love your posts always.

  10. Здравствуйте у меня rbmc 28 .я не могу горячую воду включить .хотя прочитала как вы написали.помогите пожалуйста 😔

    1. Hi Wake,

      Thank you for reaching out. Hot water works in two ways.
      – Only Hot water(온수전용): Select to provide hot water only (no floor heating /used usually in the summer)
      In this case, just push the “온수 (Hot water)” button.
      – Hot water & Floor Heating(난방+온수): for both hot water and floor heating
      In this case, push “난방 (Floor heating)” and “온수 (How water)” as well.

      If the hot water is turned on, you can see the hamburger icon with “온수” at the top right corner of the controller screen.
      I’ll add RBMC-28 model to the post today.

      Best regards,
      Jay & DY

  11. Hi, thanks for this post.

    I have a Rinnai Indoor Thermostat Type 2 (same as you have shown here). For the two months before December came along, when I was only using hot water 온수전용 for showering with with ‘water temperature’ (온수온도조절) knob to low(저온), I got my gas bills around 3000 won, but this last month when I turned on the room+water (난방온수) knob, along with turning the ‘water temperature’ (온수온도조절) knob to High(고온), my gas bill escalated to a surprising 34000 won! I used the room heating for around 7 hours every night on this setting for a month. Is it because I turned the 온수온도조절 to 고온? Please guide me how I can have a setting that wouldn’t have me incur such high bills?

    1. Hi Hiba,

      The main reason for the increased bill is because you started floor heating.
      Even I don’t know the size of your heating system and your house, 34,000 KRW a month is not a high bill.
      Please, check the monthly house heating fee of your friends and neighbors.

      Kind regards,
      Dy & Jay

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