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W8635A EQUIPMENT INTERFACE MODULE
Symptom
Heating does not come
on. System on indicator
(
= heat) displays.
Cooling does not come
on. System on indicator
(
= cool) displays.
"wait" is displayed and
the call for Cool has not
started.
nd
2
stage heat or cool
does not energize.
Fan does not come on
with a call for electric
heat.
Home and Building Control
Honeywell Inc.
Honeywell Plaza
P.O. Box 524
Minneapolis, MN 55408-0524
69-1339—2
G.H.
Rev. 6-00
Table 7. Troubleshooting Guide. (Continued)
Possible Cause
Communication is not being
completed.
Heat load at W8635A is not
connected correctly.
Communication is not being
completed.
Cool load at W8635A is not
connected correctly.
Compressor protection is in
effect.
Stage configuration not set
correctly to match the number of
selected stages.
Cool load at W8635A is not
connected correctly.
Electric heat setting is not
configured.
Fan load at W8635A is not
connected correctly.
Home and Building Control
Honeywell Limited-Honeywell Limitée
155 Gordon Baker Road
North York, Ontario
M2H 3N7
End and repeat the call for heat. Check the Flash COM
OK LED on the W8635A 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:
check that 24 Vac is present at W1 terminal.
If 24 Vac is not present:
check R to Rh connection.
If the connection is good:
replace the W8635A EIM.
End and repeat the call for cool. Check the Flash COM
OK LED on the W8635A 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:
check that 24 Vac is present at Y1 terminal.
If 24 Vac is not present:
check R to Rh to Rc jumper connection.
If the R to Rh to Rc connection is good:
replace the W8635A EIM.
Compressor protection can be set from 0 to 5 minutes
to prevent compressor damage due to rapid cycling.
Wait until the compressor protection period expires.
To bypass compressor protection during the installation
phase, see the Installer System Test section.
Set the Stage configuration in Installer Setup for two
stages or heat and/or two stages of cool.
Check that 24 Vac is present at Y2 or W2 terminal. If
24 Vac is not present, all connections are good and the
thermostat is correctly configured, replace W8635A EIM.
Set Installer Setup No. 4 to 1 for electric heat.
Check that 24 Vac is present at G terminal. If 24 Vac is
not present, all connections are good and the thermostat
is configured, replace the W8635A EIM.
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Action
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