Rinnai RU199iN Tankless Water Heater Instruction Manual
- June 13, 2024
- Rinnai
Table of Contents
Rinnai RU199iN Tankless Water Heater
The SENSEI Tankless Water Heater is designed to provide an efficient and continuous hot water supply. However, lime and scale build-up can reduce performance and damage the water heater. To address this issue, a flushing procedure has been optimized to remove lime and scale from the heat exchanger.
Product Using Instructions
Preparing the Water Heater for Flushing
- Unplug the power to the water heater until the display is not illuminated.
- Plug in the power for 20 seconds, then unplug it again. Note that using the ON/OFF button on the controller will not achieve the same results.
Flushing the Water Heater
- Close the shutoff valves on both the hot water and cold water lines (V3 and V4).
- Connect the pump outlet hose (H1) to the cold water line at the service valve (V2).
- Connect the drain hose (H3) to the hot water line at the service valve (V1).
- Pour four gallons of undiluted virgin, food-grade white vinegar into a pail.
- Place the drain hose (H3) and the hose (H2) to the pump inlet into the cleaning solution.
- Open both service valves (V1 and V2) on the hot water and cold water lines.
- Operate the pump and allow the vinegar to circulate through the water heater for at least 1 hour at a rate of 3-4 gallons per minute (11-15 liters per minute).
- If using a submersible pump, eliminate the H2 hose and place the pump in a bucket according to the pump manufacturer’s guidelines.
Rinse and Disconnect
- Turn off the pump.
- Rinse the vinegar from the water heater:
- Remove the free end of the drain hose (H3) from the pail and place it in a sink or outside to drain.
- Close service valve (V2) and open shutoff valve (V4). Do not open shutoff valve (V3).
- Allow water to flow through the water heater for five minutes.
- Close shutoff valve (V4). When the unit has finished draining, remove the in-line filter at the cold water inlet and clean out any residue. Place the filter back into the unit and open valve (V4).
- Close service valve (V1) and open shutoff valve (V3).
- Disconnect all hoses.
- Restore electrical power to the water heater.
- Discard the used vinegar. Do not reuse it for future flushes.
PURPOSE: Lime/scale build up can damage a water heater and reduce performance. The instructions below detail an optimized method to flush the heat exchanger of lime and scale build up.
PRODUCT INFORMATION
- Applicable Products: SENSEI Series Condensing Tankless Water Heaters
- Applicable Models: RU199i/e, RU180i/e, RU160i/e, RU130i/e, RUR199i/e, RUR160i/e, RSC199i/e, RSC160i/e
DETAILS
If application includes multiple units, remove the front cover and disconnect the MSB, cascade, or EZConnect™ cable from the PC board on the unit being flushed.
Preparing the Water Heater for Flushing
Use the following procedure to ensure interval control valves are positioned for optimal flushing.
- Unplug (disconnect) power to the water heater until display is not illuminated.
- Plug in (connect) power for 20 seconds, then unplug (disconnect) power to the water heater.
- Note: Power must be unplugged. The ON/OFF button on the controller will not achieve the same results.
- Flushing the Water Heater:
- Close the shutoff valves on both the hot water and cold water lines (V3 and V4).
- Connect pump outlet hose (H1) to the cold water line at service valve (V2).
- Connect drain hose (H3) to the hot water line at service valve (V1).
- Pour four gallons of undiluted virgin, food grade, white vinegar into pail.
- Place the drain hose (H3) and the hose (H2) to the pump inlet into the cleaning solution.
- Open both service valves (V1 and V2) on the hot water and cold water lines.
- Operate the pump and allow the vinegar to circulate through the water heater for at least 1 hour at a rate of 3-4 gallons per minute (11-15 liters per minute).
- If using a submersible pump, eliminate H2 hose and place pump in bucket per pump manufacturer’s guidelines.
- Rinse and Disconnect:
- Turn off the pump.
- Rinse the vinegar from the water heater as follows (refer to Figure 1 on front page):
- Remove the free end of the drain hose (H3) from the pail. Place in sink or outside to drain.
- Close service valve (V2) and open shutoff valve (V4). Do not open shutoff valve (V3).
- Allow water to flow through the water heater for five minutes.
- Close shutoff valve (V4). When unit has finished draining, remove the in-line filter at the cold water inlet and clean out any residue. Place filter back into unit and open valve (V4).
- Close service valve (V1) and open shutoff valve (V3).
- Disconnect all hoses.
- Restore electrical power to the water heater.
- Discard used vinegar. Do not reuse for future flushes.
Best Practices
- Always leave inlet water filter(s) in place in tankless unit during flushing.
- Clean filters immediately after flush is complete.
- If pump flow decreases significantly during flush, pause pump, clean filter(s), replace and resume.
VIDEO TUTORIAL
Scan the QR code below for a video tutorial:
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