Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater DISPLAY DASHES Error Fix: Temperature Sensor Error

The digital temperature display shows dashes (--) instead of a temperature reading. This indicates the inlet or outlet temperature sensor (thermistor) is reading out of range, is disconnected, or has failed. Remove the front cover and check the sensor wire connections at the PCB. If connections are secure, test the thermistor resistance — it should change predictably with water temperature. Replace the sensor if readings are erratic, open circuit, or shorted.

warning2 fixes available✨ Free fix available

Quick Answer

Error DISPLAY DASHES on the Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater means: Temperature Sensor Error. The top-ranked community fix is “Test and Replace Faulty Temperature Sensor Thermistor” (medium difficulty, ~45 min, DIY cost: $10-$20). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · water heater

Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.

When to Call a Professional

While many water heater repairs can be done safely at home, consider hiring a qualified technician if:

The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $120-$180.

Other Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater Error Codes

ELEMENT LED OFF

Elements Not Firing — No Demand or No Power

2 fixes

ELEMENT LED ON

Heating Elements Active — Normal

2 fixes

LOW TEMP OUTPUT

Insufficient Temperature Rise — Unit Undersized

2 fixes

NO DISPLAY

No Power to Unit — Display Dark

2 fixes

People Also Ask About Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater Error DISPLAY DASHES

What does error code DISPLAY DASHES mean on a Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater?

Error code DISPLAY DASHES on the Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater means: Temperature Sensor Error. The digital temperature display shows dashes (--) instead of a temperature reading. This indicates the inlet or outlet temperature sensor (thermistor) is reading out of range, is disconnected, or has failed. Remove the front cover and check the sensor wire connections at the PCB. If connections are secure, test the thermistor resistance — it should change predictably with water temperature. Replace the sensor if readings are erratic, open circuit, or shorted.

How do I fix error code DISPLAY DASHES on my Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater?

The most successful fix is "Test and Replace Faulty Temperature Sensor Thermistor" (medium difficulty, ~45 minutes). Estimated DIY cost: $10-$20. HomeMD has 2 community-ranked fixes for this error.

Is error code DISPLAY DASHES on a Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater serious?

This error is rated warning severity. It is generally not urgent and can often be resolved with a simple DIY fix.

Can I fix Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater error DISPLAY DASHES myself?

Yes — the top-ranked community fix ("Test and Replace Faulty Temperature Sensor Thermistor") is rated medium difficulty and takes about 45 minutes. Tools needed: Phillips screwdriver, Multimeter, Small container for warm water.

How much does it cost to repair Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater error DISPLAY DASHES?

DIY cost: $10-$20. Professional repair typically costs $120-$180. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater have?

The Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater has 4 other known error codes, including: ELEMENT LED OFF (Elements Not Firing — No Demand or No Power), ELEMENT LED ON (Heating Elements Active — Normal), LOW TEMP OUTPUT (Insufficient Temperature Rise — Unit Undersized), NO DISPLAY (No Power to Unit — Display Dark).

What other error codes does the Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater have?

The Rheem Rheem RTEX-13 13kW Point-of-Use Electric Tankless Water Heater has 4 other known error codes:

ELEMENT LED OFF — Elements Not Firing — No Demand or No Power (2 fixes)
ELEMENT LED ON — Heating Elements Active — Normal (2 fixes)
LOW TEMP OUTPUT — Insufficient Temperature Rise — Unit Undersized (2 fixes)
NO DISPLAY — No Power to Unit — Display Dark (2 fixes)

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