Troubleshooting guide – Honeywell W8635A User Manual

Page 5

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W8635A EQUIPMENT INTERFACE MODULE

5

69-1339—2

TROUBLESHOOTING GUIDE

Refer to Table 7 for troubleshooting information.

Fan and Damper Test (Damper Test available only when using W8703A)

40

Enter Fan and Damper test.

41

Fan turns on; damper for this zone opens.

42

Damper closes for this zone (if not already closed); fan stays on.

41

Damper opens for this zone.

40

Fan turns off.

Key Operation Test

60

Enter Key Operation test.

Press any key to test if the key is functional. Each time a key is pressed, a different number is displayed. This
indicates the key is functioning properly. Pressing

enters the next test.

Thermostat Information

70

Enter Thermostat Information mode.

71

Production date code is displayed. The first two large digits are
the month and the third digit is the last digit of the year (example:
031 = March 2001).

72

Software identification code is displayed.

73

Software revision number is displayed.

74

EEPROM identification code is displayed.

Exit Installer Test Mode

Thermostat returns to normal operating mode.

Table 6. Installer System Test Options. (Continued)

Key to Press

Test Number

Description

Run

Program

Table 7. Troubleshooting Guide.

Symptom

Possible Cause

Action

Display does not come
on at thermostat.

Thermostat is not being powered. Check if the thermostat is mounted and latched on the

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 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.

“1 COM”, “2 COM” or
“3 COM” is displayed.

Thermostat is unable to
communicate with the W8635A.

Check the connection to terminal 1 at the thermostat
and W8635A EIM:

—replace any broken wires.

cycle power.

System Switch setting
displays “off only.”

During Discovery Mode, the
thermostat did not correctly set
the number of heat or cool stages.

Manually run Discovery Mode; see Installer Setup.

manually configure heat and/or cool stages

(Installer Setup 5 and 8).

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