1. Introduction
This manual provides essential information for the safe and efficient installation, operation, and maintenance of your Rheem RTGH-90DVLN-3 Natural Gas Condensing Tankless Water Heater. This super high-efficiency indoor unit delivers continuous hot water with minimal wait, saving time, energy, and water. It features exclusive Hot Start Programming to eliminate cold water bursts and an Overheat Film Wrap for heat exchanger protection. Its compact, wall-mount design allows for installation in small spaces.
2. Safety Information
WARNING: Improper installation, adjustment, alteration, service, or maintenance can cause property damage, injury, or death. Read this manual thoroughly before installing or servicing this water heater.
- Ensure all gas and electrical connections are made by a qualified professional in accordance with local codes and regulations.
- Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.
- This appliance must be properly vented. Blocked or improper venting can cause carbon monoxide poisoning.
- Hot water can cause severe burns. Exercise caution when setting water temperature and using hot water.
- Always turn off the gas supply and electrical power to the unit before performing any maintenance or service.
3. Setup and Installation
The Rheem RTGH-90DVLN-3 is designed for indoor installation and features a compact, wall-mount design. Proper venting is crucial for safe operation.
3.1 Unit Overview
Figure 3.1: Front view of the Rheem RTGH-90DVLN-3 Tankless Water Heater, showing the digital display and control buttons.
Figure 3.2: Side view of the Rheem RTGH-90DVLN-3 Tankless Water Heater, highlighting its slim profile.
3.2 Compact Design and Installation
The unit's compact size and wall-mount capability allow for flexible installation in various indoor spaces, including utility closets. It requires minimal side-to-side clearance (1/2 inch) and zero front and back clearance.
Figure 3.3: Example installation of the Rheem RTGH-90DVLN-3 in a utility closet, demonstrating its space-saving design.
Figure 3.4: Key features of the Rheem RTGH-90DVLN-3, including compact design, continuous hot water, integrated digital control, and high energy efficiency.
3.3 Venting Requirements
This condensing tankless water heater utilizes PVC for venting. Ensure proper vent pipe sizing and installation according to the provided instructions and local building codes.
Figure 3.5: Illustration showing the PVC venting for the Rheem RTGH-90DVLN-3 condensing tankless water heater.
3.4 Installation Overview Video
Video 3.1: An introductory video to the Rheem Condensing RTGH Tankless Gas Water Heaters, providing an overview of the series and its features.
4. Operating Instructions
Your Rheem tankless water heater is designed for ease of use. The integrated digital display allows for precise temperature control.
4.1 Setting Water Temperature
The available temperature settings range from 100°F to 140°F, with a default setting of 120°F. Use the up and down arrows on the digital display to adjust the desired output temperature.
Figure 4.1: Close-up of the integrated digital control panel, showing temperature display and adjustment buttons.
4.2 Hot Start Programming
The exclusive Hot Start Programming feature keeps the water heater in a ready state, minimizing cold water bursts during back-to-back uses. This ensures continuous hot water delivery when you need it.
4.3 Operational Flow
Video 4.1: This video details the features and benefits of the RTGH-3 Condensing Super High Efficiency series, including how it operates to provide hot water.
5. Maintenance
Regular maintenance ensures the longevity and efficient operation of your tankless water heater.
- Filter Cleaning: Periodically clean the water inlet filter to prevent sediment buildup. The frequency depends on your water quality.
- Flushing: It is recommended to flush the unit every few years to remove mineral deposits from the heat exchanger. This process typically involves isolating the unit, connecting a pump, and circulating a descaling solution. Consult a qualified technician for this procedure.
- Visual Inspection: Regularly inspect the unit for any signs of leaks, corrosion, or damage to the venting system.
6. Troubleshooting
If you encounter issues with your water heater, refer to the following common troubleshooting tips. For complex problems, contact a qualified service technician.
| Problem | Possible Cause | Solution |
|---|---|---|
| No hot water or insufficient hot water |
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| Error code displayed (e.g., P1) |
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| Water temperature fluctuates |
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7. Specifications
| Feature | Detail |
|---|---|
| Brand | Rheem |
| Model Number | RTGH-90DVLN-3 |
| Product Dimensions (W x H) | 17.7"W x 23.7"H |
| Item Depth | 9.8 inches |
| Item Weight | 59.9 pounds |
| Power Source | Natural Gas |
| Heat Output | 180,000 British Thermal Units (BTUs) |
| Maximum Flow Rate | 9 Gallons Per Minute (GPM) |
| Available Temperature Settings | 100°F to 140°F (default 120°F) |
| Efficiency | 0.93 |
| Voltage | 120 Volts |
| Style | Indoor Installation |
| Mounting Type | Wall |
| Special Features | Hot Start Programming, Overheat Film Wrap, LED Display, Direct Vent |
| UPC | 662021564307 |
7.1 Performance Guide
Figure 7.1: Performance guide for RTGH series, showing water flow (GPM) at various temperature rises (°F) for different models. This model (RTGH-90DVLN-3) provides 9.0 GPM at a 35°F temperature rise.
8. Warranty Information
The Rheem RTGH-90DVLN-3 Tankless Water Heater is covered by the following manufacturer warranties:
- Labor: 1 year
- Heat Exchanger: 15 years
- Parts: 5 years
Please retain your proof of purchase for warranty claims. For full warranty details, refer to the official Rheem warranty documentation included with your product or visit the Rheem website.
9. Customer Support
For technical assistance, service, or to locate a qualified professional for installation or repair, please contact Rheem customer support or visit the official Rheem website.
Rheem Official Website: www.rheem.com
