Honeywell Y9420S User Manual page 28

FAQ AND TROUBLESHOOTING
How reliable is 2-way RF communication?
The 2-way RF communication (also known as wireless communication) used by
Honeywell is extremely robust and reliable. When installed correctly the Signal
Strength test feature allows the Installer to locate the system components where
mutual signal reception is strong. During communication, signals are sent several
times to ensure receipt, and if any message is garbled, the error detection software
recognises this and ensures the message is repeated again.
What do I do if RF communication is lost?
Follow the steps in the Troubleshooting Guide on the next page. The most likely
cause for loss of communications is the DT92E batteries running low on power. This
will be indicated on the DT92E display by a flashing battery symbol, or the display
may even be blank. Simply replace the batteries (as shown on page 21) and wait a
few minutes for communications to become re-established.
If this does not resolve the problem it may be that the RF signal path between
the ST9420C and the DT92E is blocked by a metal object. Check the direct path
between the two devices and reposition any object that may be blocking the signal,
or move the thermostat.
How do I know when to change the batteries in the CS92A
cylinder sensor?
If the CS92A batteries need changing, the ST9420C will show the message "SENSOR
LOW BATT" and the tap symbol will flash. You can confirm this by pressing the
CS92A button, whereupon the red light will give a brief flash every second to indicate
a low battery state. It is important to change the CS92A batteries as soon as the low
battery condition is indicated, as reduced battery power may affect the RF signal
strength and impair RF communications.
How do I know when to change the batteries in the DT92E
room thermostat?
If the DT92E batteries need changing, the battery symbol will flash on the DT92E
display. DT92E will continue to operate for at least 4 weeks after the indicator begins
to flash. The ST9420C will also show the message 'SENSOR LOW BATT' and the
radiator symbol will flash. It is important to change the DT92E batteries as soon
as the low battery condition is indicated, as reduced battery power may affect the
RF signal strength and impair RF communications.
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