Important 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. This appliance must be installed by a qualified electrician and plumber in accordance with all national, state, and local electrical and plumbing codes.
- Always disconnect power before servicing the unit.
- Do not operate if any part is submerged in water.
- Ensure proper grounding to prevent electrical shock.
- Maintain adequate clearance around the unit for ventilation and service.
Product Overview
The Rheem RTEX-36 is a 36kW electric tankless water heater designed to provide on-demand hot water for residential or commercial applications. This unit features an external adjustable temperature control and 3/4 inch NPT connections for easy plumbing integration. Its compact design allows for indoor wall mounting, saving space and providing efficient hot water delivery.
Figure 1: Front view of the Rheem RTEX-36 Electric Tankless Water Heater, highlighting its compact design and digital temperature control interface.
Key Features:
- Energy efficient operation with 99.8% efficiency.
- Digital temperature control for precise hot water settings.
- Compact and stylish design for indoor wall mounting.
- Provides up to 6 gallons per minute (GPM) flow rate.
- Adjustable temperature up to 140°F (60°C).
Specifications
| Feature | Detail |
|---|---|
| Model Number | RTEX-36 |
| Brand | Rheem |
| Wattage | 36 kW |
| Voltage | 240 Volts |
| Maximum Flow Rate | 6 Gallons Per Minute (GPM) |
| Maximum Temperature | 140°F (60°C) |
| Efficiency | 99.8% |
| Mounting Type | Wall |
| Item Weight | 24.3 pounds |
| Package Dimensions | 24 x 21.1 x 6.3 inches |
Installation
Installation of the Rheem RTEX-36 electric tankless water heater requires adherence to specific electrical and plumbing codes. It is strongly recommended that installation be performed by a qualified and licensed professional electrician and plumber.
General Guidelines:
- Location: Choose an indoor location that is protected from freezing temperatures and easily accessible for maintenance. Ensure adequate clearance around the unit.
- Mounting: Securely mount the unit to a wall using appropriate fasteners. Refer to the mounting template provided with the unit for precise hole placement.
- Plumbing Connections: Connect the cold water inlet and hot water outlet to the unit's 3/4 inch NPT connections. Ensure all connections are watertight. Install shut-off valves on both inlet and outlet lines.
- Electrical Connections: This unit requires a dedicated 240V electrical circuit. Consult the wiring diagram in the full installation manual for correct wire sizing and breaker requirements. All electrical work must comply with local and national electrical codes.
- Ventilation: No special ventilation is required for electric tankless water heaters, but ensure the unit is not enclosed in an airtight space.
- Initial Startup: Before applying power, ensure the unit is completely filled with water to prevent damage to the heating elements. Open a hot water faucet to purge air from the system.
For detailed installation instructions, including wiring diagrams and plumbing schematics, please refer to the complete installation guide provided with your product.
Operation
Once properly installed and powered, the Rheem RTEX-36 is designed for straightforward operation.
Turning On/Off:
- To turn the unit on, ensure the circuit breaker supplying power to the water heater is in the "ON" position. The digital display on the unit will illuminate.
- To turn the unit off, switch the dedicated circuit breaker to the "OFF" position.
Adjusting Temperature:
- The RTEX-36 features an external digital temperature control. Use the up and down arrows on the unit's display to adjust the desired hot water temperature.
- The temperature can be set between 80°F (27°C) and 140°F (60°C).
- The display will show the set temperature. Once water flows through the unit, it will heat to the set temperature.
Digital Display:
- The digital display indicates the current temperature setting.
- During operation, it may show flow rate or power consumption depending on the model's specific features.
- Error codes, if any, will also be displayed here. Refer to the troubleshooting section for error code explanations.
Maintenance
Regular maintenance ensures the longevity and efficient operation of your Rheem RTEX-36 water heater. Always disconnect power to the unit before performing any maintenance.
Annual Flushing:
- In areas with hard water, mineral deposits can accumulate in the heating elements and heat exchanger. It is recommended to flush the unit annually with a descaling solution.
- This process typically involves isolating the unit, connecting a pump and bucket system, and circulating a food-grade descaling solution through the heater.
- Refer to the full maintenance guide for detailed instructions on descaling.
Inlet Filter Cleaning:
- Some models include an inlet water filter. Periodically check and clean this filter to ensure optimal water flow and prevent debris from entering the unit.
General Inspection:
- Periodically inspect the unit for any signs of leaks, corrosion, or loose electrical connections. Address any issues promptly.
Troubleshooting
If your Rheem RTEX-36 water heater is not functioning as expected, consult the following common issues and solutions. Always disconnect power before attempting any repairs.
| Problem | Possible Cause | Solution |
|---|---|---|
| No hot water / Unit not turning on | No power; Circuit breaker tripped; Water flow too low. | Check circuit breaker; Ensure adequate water flow (minimum activation flow rate); Verify electrical connections. |
| Water not hot enough | Temperature setting too low; High incoming water temperature; Excessive flow rate; Mineral buildup. | Increase temperature setting; Reduce hot water flow; Perform descaling maintenance. |
| Fluctuating water temperature | Inconsistent water pressure; Air in the system; Multiple hot water demands. | Check water pressure regulator; Purge air from lines; Avoid simultaneous high-demand uses. |
| Error code displayed | Specific internal fault. | Refer to the complete user manual for a list of error codes and their corresponding solutions. If the issue persists, contact qualified service personnel. |
If you are unable to resolve an issue after consulting this section, please contact Rheem customer support or a qualified service technician.
Warranty and Support
Rheem products are manufactured to high-quality standards and come with a limited warranty. Specific warranty terms and conditions vary by model and region. Please retain your proof of purchase for warranty claims.
For Warranty Information and Technical Support:
- Visit the official Rheem website: www.rheem.com
- Contact Rheem Customer Service directly. Refer to the contact information provided in your product packaging or on the official website.
- Ensure you have your model number (RTEX-36) and serial number ready when contacting support.