Chromagen Error E1 — Upper Temperature Sensor Fault

What Does This Error Mean?

Error E1 means the upper temperature sensor inside your solar tank has failed or become disconnected. The heater cannot read the water temperature at the top of the tank and has stopped heating as a safety precaution.

Affected Models

Chromagen CR Series
Chromagen Optima
Chromagen Crown
Chromagen Prisma

Common Causes

Faulty or broken upper (top) temperature sensor (NTC probe)
Sensor wire disconnected or corroded
Water damage to sensor connector
Sensor reading out of normal range due to extreme temperature

How to Fix It

Check the controller display

If E1 is flashing continuously, the fault is active. If it shows briefly then clears, it may be an intermittent connection issue.
Turn the system off and back on

Switch off the controller at the wall for 30 seconds, then restore power. If E1 returns immediately, the sensor itself is faulty.
Inspect visible wiring (if accessible)

If you can safely access the controller box, check whether any sensor wires appear loose or corroded at their connectors. Do not attempt repairs yourself — just note what you see for the technician.
Book a service call

The upper sensor (also called T1 or TS1) is a standard replacement part. A technician can swap it in under an hour.

When to Call a Professional

Yes — sensor replacement requires draining part of the system and accessing internal components. Call a Chromagen-authorised technician or a solar plumber.

What Is Error E1 on a Chromagen Solar Water Heater?

Error E1 appears on the Chromagen digital controller when the upper temperature sensor (also labelled T1 or TS1) has failed, disconnected, or is reading an impossible value.

The sensor is a small probe inside or on the solar storage tank that tells the controller how hot the water is at the top. Without it, the system cannot regulate heating safely and shuts down the heating circuit.

Is This an Emergency?

Not immediately — your stored hot water remains safe to use. But the system will not reheat until the fault is cleared, so you will run out of hot water faster than usual. Arrange a service call within a day or two.

What a Technician Will Do

A qualified technician will:

Test the sensor resistance with a multimeter to confirm it has failed
Drain the relevant section if needed
Replace the upper NTC sensor with a Chromagen-compatible part
Reset the controller and verify correct temperature readings

Frequently Asked Questions

Can I still use hot water while E1 is showing?

You may still have stored hot water in the tank from before the fault occurred, but the system is not actively heating. Use it sparingly and arrange a repair promptly.

How much does a Chromagen sensor replacement cost?

The sensor itself is inexpensive — usually under $30. Labour for a call-out typically adds $80–$150 depending on your location.