Honeywell manual Troubleshooting the CM721, Symptom Remedy

Page 7

TROUBLESHOOTING THE CM721

Symptom

 

 

Remedy

 

Blank Display (Power Loss).

Check batteries are installed by removing the battery

 

 

 

cover.

 

 

 

 

Check batteries have been installed in the correct

 

 

 

orientation.

 

 

 

 

Replace the batteries.

 

 

 

 

 

Display shows flashing

The batteries in the thermostat are low on power

symbol.

 

 

- Replace the batteries.

 

 

 

 

Display shows

 

symbol.

A fault has occurred in your heating system. Remove

 

 

 

 

and re-insert the batteries.

 

 

 

If the

 

 

symbol does not clear after a few minutes

 

 

 

 

 

 

 

contact your installer.

 

 

Display shows the word 'SERVICE'

Your installer has set a scheduled maintenance alert

 

 

 

period on your CM721 as a recommendation that your

 

 

 

heating system should receive a routine inspection.

 

 

 

Call your installer to arrange a maintenance visit.

 

 

 

Note: The CM721 and heating system will continue to

 

 

 

operate as normal.

 

 

BDR91 red LED is constantly on

RF communication lost due to the wrong location of

or flashing

 

 

the room unit - Hook the room unit back on the wall

 

 

 

bracket where RF communication was reliable.

 

 

 

Call installer

 

 

 

 

NOTE: You can control the boiler manually when the

 

 

 

RF communication is lost: Press the BDR91 push

 

 

 

button to switch the boiler on and off. When the green

 

 

 

LED is on – the boiler is on.

 

 

 

 

 

 

 

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Contents CM721 CM727 Controls Layout FeaturesDescription CM721 User GuideRunning the Built-in Heating Program SETTING-UP the CM721Installing the Batteries Setting the Date and TimeModifying the Heating Program Programming the CM721Built-in Heating Program Reviewing the Heating ProgramOperating the CM721 Choosing the Operating ModeAdjusting the Time Using the Special FeaturesAutomatic Summer/Winter Time Change How do I set one temperature for the whole day?Symptom Remedy Troubleshooting the CM721CM727 CM727 User GuideSETTING-UP the CM727 Programming the CM727 Time 800 1000 1800 2300 Temperature 21C 16CMonday to Friday Period Operating the CM727 Holiday Function Using the Special FunctionsTo set the Holiday function Service indicator optional FAQ’s Troubleshooting the CM727 An explanation for householders What is a Programmable Room THERMOSTAT?