Rinnai REU-KBD3237FFUD-US User Manual

Direct Vent Tankless Water Heater
Operaon Instrucons
Important Facts about your Water Heater
Thank you for purchasing a Rinnai Tankless Water Heater. For proper operaon and safety, it is
important to follow the instrucons and adhere to all safety precauons.
Read all of the instrucons and the warranty thoroughly before operang this water heater. Keep this
manual in a safe place.
NOTICE: Rinnai somemes shares customer contact informaon with businesses that we believe provide
products or services that may be useful to you. By providing this informaon, you agree that we can
share your contact informaon for this purpose. If you prefer not to have your informaon shared with
these businesses, please contact customer service and ask not to have your informaon shared. We
will however, connue to contact you with informaon relevant to the product(s) you registered and/or
you account with us.
— Do not store or use gasoline or other ammable vapors and liquids in the vicinity of this or any
other appliance.
— WHAT TO DO IF YOU SMELL GAS
 Do not try to light any appliance.
 Do not touch any electrical switch; do not use any phone in your building.
 Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s
instrucons.
 If you cannot reach your gas supplier, call the re department.
— Installaon and service must be performed by a licensed professional.
If the informaon in these instrucons is not followed exactly, a re or
explosion may result causing property damage, personal injury, or death.
WARNING
FOR INDOOR APPLICATIONS ONLY
RUC80i .................. REU-KBD2530FFUD-US
RUC90i .................. REU-KBD2934FFUD-US
RUC98i .................. REU-KBD3237FFUD-US
FOR OUTDOOR APPLICATIONS ONLY
RU80e ................... REU-KB2530WD-US
RU90e ................... REU-KB2934WD-US
RU98e ................... REU-KB3237WD-US
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Rinnai REU-KBD3237FFUD-US Specifications

General

Type	Tankless
Fuel Type	Natural Gas
Heating Capacity	199, 000 BTU
Category	Residential
Condensing	Yes
Maximum BTU Input	199, 000 BTU
Maximum Temperature	140°F
Ignition Type	Electronic
Venting	Direct Vent
Flow Rate	3.7 GPM
Warranty	12 years heat exchanger, 5 years parts

Summary

Safe Operation Guidelines

General Safety Warnings

Highlights critical safety warnings, including fire/explosion risks, pilotless ignition, and handling of submerged appliances.

Operating and Shutdown Instructions

Temperature Controller Usage

Setting Water Temperature

Temperature Control Operation

Guides users on how to turn on the heater, activate priority mode, and adjust the desired water temperature using the controller.

Scalding Hazard Warning

Emphasizes the danger of hot water over 125°F (52°C), detailing burn risks at different temperatures and vulnerable groups.

Temperature Settings and Options

Troubleshooting with Diagnostic Codes

Diagnostic Code Reference

Provides a comprehensive list of diagnostic codes, their definitions, and recommended remedies, often requiring professional intervention.

Diagnostic Code Reference (Continued)

Continues the list of diagnostic codes and their remedies, covering issues like sensors, PC board, and scale build-up.

Required Maintenance Procedures

General Maintenance and Cleaning

Maintenance and Seasonal Protection

Pressure Relief Valve and Flame Inspection

Winterization and Freeze Protection

Heat Exchanger Maintenance

Flushing the Heat Exchanger

Provides a detailed, step-by-step procedure for flushing the heat exchanger with vinegar to remove lime build-up and prevent damage.

Draining and Freeze Prevention

Manual Draining Procedure

Product Warranty Information

Warranty Coverage Details

Explains what the Rinnai Standard Limited Warranty covers, the duration for different components and applications, and conditions for coverage.

Service and Exclusions