This guide is for Honeywell Home T6R-HW owners who see an alert on the thermostat. The list comes from the T6/T6R user guide from Resideo, which makes Honeywell Home products.

What This Problem Means

The T6R-HW shows an alert when something needs attention: a Wi-Fi or internet problem, a lost link to the receiver box, a fault in the thermostat itself, or a fault the boiler has reported. Resideo’s T6/T6R user guide covers the wired T6 and the wireless T6R, so two sensor alerts it lists for the T6 only are left out of the table.

Common Symptoms

• An alert in capital letters on the thermostat screen
• A Wi-Fi, receiver box or boiler alert
• A thermostat fault such as INTERNAL MEMORY ERROR
• A blank thermostat screen

Safe Checks You Can Try

1. Read the alert

Find the alert in the table below. The wording is Resideo’s.

2. Follow Resideo’s advice for that alert

For Wi-Fi alerts, see the T6R-HW Wi-Fi guide; for receiver alerts, see the receiver guide; for boiler alerts, see the boiler fault guide.

3. Contact your installer for thermostat faults

WIFI RADIO ERROR, INTERNAL MEMORY ERROR and THERMOSTAT TEMPERATURE SENSOR ERROR each mean part of the thermostat is faulty, and Resideo says to contact your installer.

4. Dismiss or snooze the alert

Touch the alert to dismiss it, or snooze it for 7 days.

5. Blank screen: check the power

Resideo says to make sure the power is switched on, and to check the circuit breaker and reset it if necessary.

T6R-HW alerts explained

The list comes from Resideo’s T6/T6R user guide. The guide also lists INDOOR TEMPERATURE SENSOR ERROR and OUTDOOR TEMPERATURE SENSOR ERROR, which it marks as T6 only (the wired model). For BOILER HAS LOW WATER PRESSURE, use your boiler maker’s instructions for topping up. Don’t open the boiler or touch any wiring: any work on the boiler itself must be done by a Gas Safe registered engineer.

When To Contact Support

If none of these steps fix it, contact Resideo, which makes Honeywell Home products, through Resideo’s UK site.