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Rheem Tankless water heater Professional Classic Series: RTEX-36

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Rheem Residential water heating Tankless water heater Repair, maintenance, and replacement planning
Rheem Professional Classic Series: RTEX-36 product image

Technical Specifications

Product Specs

  • ON/OFF Dial Control with adjustable digital temperature display
  • Self-modulating power control
  • Flow Rate: up to 8.8 GPM
  • Bottom 3/4" NPT water connections
  • 6.5-6.5 GPM
  • SKU: RTEX-36 (208V PERFORMANCE)
  • Warranty Years: 5
  • Model: Professional Classic Series Tankless Electric RTEX-36
  • GPM: 6.5
  • Depth: 3.5"
  • Height: 18.25"
  • Width: 21.63"
  • Single Shower Minutes: 9999
  • Number Back To Back Showers: 9999
  • Install Location: Indoor
  • High Efficiency: Yes
  • Kilowatts: 27
  • Water Connector Size 32: 24
  • Amps: 150
  • Recommended Breaker Size: 4x40
  • Brand: Rheem
  • Model or series: Professional Classic Series: RTEX-36
  • Equipment type: Tankless water heater
  • Product group: Residential water heating
  • System role: Water-heating equipment for domestic or commercial hot-water loads
  • Application: Domestic or commercial hot-water applications when model capacity is appropriate
  • Compatibility check: Verify fuel type, venting, electrical requirements, capacity, controls, and installation clearances.
  • Verified source: rheem.com

Useful troubleshooting details

  • Confirm the exact Rheem model or SKU, serial number, equipment age, and installation location before scheduling service.
  • Share photos of the data plate, equipment cabinet, nearby controls, access area, and any visible leaks, ice, alerts, or error codes.
  • For water-heating equipment, note hot-water symptoms, temperature swings, pressure concerns, venting, condensate, scale, and maintenance history.
  • Imported official SKU example: RTEX-36 (208V PERFORMANCE).

Service planning

How GreenFlow handles Professional Classic Series: RTEX-36 requests

1

Identify the equipment

Confirm the model or series name, serial number if available, photos, and whether the unit is roof, exterior, basement, or mechanical-room equipment.

2

Describe the service issue

Share no heat, no cooling, weak airflow, error codes, alarms, leaks, noise, control problems, or comfort complaints.

3

Review access and history

Include access notes, tenant or business-hour constraints, filter status, recent repairs, and maintenance records when available.

4

Plan the next step

GreenFlow can route the request for diagnostics, repair planning, maintenance, replacement scope, or related system upgrades.

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Our Happy Customers

Michele Z.

Andrey was professional, prompt, smart, thorough and exceedingly pleasant. We are likely switching our current HVAC company to Green Flow.

Randy J.

Thanks to Andrey for an amazingly quick response to my request for a service call. He diagnosed and fixed my issue within 24 hours of my asking for help. Excellent service. Thanks.

Ray

Just had a service call because my tankless water heater stopped working with E110 code. Andrey located the root cause real quick and fixed the issue within half an hour, also gave reasonable recommendations for further maintenance.

Jenny W.

Great service! On time, knowledgeable & professional

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