Honeywell T8635L Installation Instructions Manual page 16

T8635L MICROELECTRONIC COMMUNICATING PROGRAMMABLE THERMOSTAT
Symptom
Display does not Thermostat is not being powered. Check if the thermostat is mounted and latched on the
come on.
"1 COM", "2 COM", Thermostat is not communicating
or "3 COM" is correctly with the W8835 or
displayed. W8635A,B.
"4 COM" is More than one thermostat is set to
displayed on left the same zone number.
side of the display.
5 COM Zone 0 was found in a zoned
system
6 COM Zone 1 was not found.
7 COM System is configured to use
external timer.
System switch During Automatic Discovery
setting displays "off mode, the thermostat did not
only." correctly set the number of heat or
cool stages.
Thermostat is Thermostat zone number is not
calling for heat or set to the corresponding W8703
zone number.
cool; or
displays and the
Terminal 1 on W8703 Damper
corresponding
Interface Module is not properly
damper does not
connected.
open.
W8703 Damper Interface Module
is defective.
Heating does not Communication is not being
come on. System completed.
on indicator
displays.
Heat load at W8635 EIM is not
connected correctly.
69-1331—5
Table 10. Troubleshooting Information.
Possible Cause
wallplate; if not:
—mount and latch the thermostat on the wallplate.
Check if the circuit breaker is tripped; if it is:
—reset the circuit breaker.
Check if the fuse in the fuse box is blown; if it is:
—replace the fuse.
Check if the power switch at the equipment is in the Off
position; if it is:
—set to the On position.
Check for 24 vac on terminals 2 and 3:
—replace any broken wires.
If 24 Vac is present on terminals 2 and 3, replace the
thermostat.
Check the connection to terminal 1 at the thermostat and
W8835 or W8635 EIM:
—replace any broken wires.
—cycle power.
Enter Installer Setup and change Installer Setup Number 1
to another value (1-3) that is different from the thermostat
with the same zone number.
Enter Installer Setup and change Installer Setup Number 1
to another value (1-9) that corresponds to the zone it is
controlling.
Enter Installer Setup on the Zone 1 Thermostat and
change Installer Setup Number 1 to 1.
The external timer function is not currently available. Enter
Installer Setup and change Installer Setup 43 to 0.
Run Automatic Discovery mode by cycling power to the
equipment.
Manually run Discovery mode in Installer Setup.
Manually configure heat and/or cool stages (Installer
Setups 5, 8 and 9).
Set zone number at the thermostat to correspond with the
correct zone number for the W8703 Damper Interface
Module.
Properly connect terminal 1 on the W8703 Damper
Interface Module.
If the W8703 indicates the damper is closed (red LED
lights), replace the W8703 Damper Interface Module.
End the call and repeat the call. Check the Flash Com OK
LED on the W8835 or W8635 EIM while the call is being
made.
If the Flash Com OK LED does not blink:
—check communication bus wiring.
If the Flash Com OK LED blinks correctly:
—check that 24 Vac is present at W1 or W1/Y1 terminal,
depending on which equipment module is being used.
If 24 Vac is not present, check the R to Rh connection. If
the connection is good, replace the W8835 or W8635 EIM.
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Action