VISIONPRO
®
IAQ TOTAL HOME COMFORT SYSTEM
68-0287—1
36
Cooling does not turn on (“Cool
On” is solid in the display)
Cooling Equipment failure
Check for 24 Vac at the equipment on the secondary side
of the transformer between power and common. If voltage
is not present check the cooling equipment to find the
cause of the problem.
Check for 24 Vac between the cool terminal(s) on the
equipment interface Module and transformer common. If
present check cooling equipment to find the cause of the
problem.
Loose or broken wire connection
between Equipment Interface
Module and cooling equipment.
Check for 24 Vac between the cool terminal(s) on the
cooling equipment and system transformer common. If
voltage is not present check for loose or broken wires
between the EIM and cooling equipment.
Communication is not being
completed
End the call for cool at the thermostat then repeat the call
for cool. Check the communication LED on the EIM board.
— If the LED does not blink, check communication
wiring (wire between terminal 1 on both the EIM
and thermostat.
— If the LED does blinks correctly, check for 24 Vac
between heating terminals on the EIM and the sys-
tem common.
If 24 Vac is not present check the R to Rh connection on
the EIM, if the connection is good replace the EIM.
2nd stage heat or cool does not
energize
Stage configuration is not set
correctly to match the number of
selected stage
Set the stage configuration in installer setup for additional
stages of cool (ISU 174) or additional stages of heat (ISU
176).
Terminals not connected properly at
EIM
Check that 24 Vac is present at W2/AUX and W3/AUX2 for
2nd and 3rd stages of conventional heating and for 3rd and
4th stages of heat pump heating. Also check that 24VAC is
present at Y2 for 2nd stage of cooling or 2nd stage heat in
heat pump applications.
“Err” appears in time field of
home screen on thermostat
Thermostat has detected an error
on the communication bus
Refer to error code section for more information.
Fan does not turn on in a call for
heat (electric furnace).
Fan Control in Heating is set to Gas
or Oil Furnace (Setting 0180).
Set Fan Control in Heating to Electric Furnace (Setting
0180).
Heat pump puts out cool air in
the heat mode and warm air in
the cool mode.
Changeover Valve (Installer Setup
Number 0190) is not configured to
match the changeover required by
the installed heat pump.
Set Changeover Valve (Installer Setup Number 0190) to
match the changeover required by the installed heat pump.
Both the heating and cooling
equipment are running at the
same time.
The heating equipment is not a heat
pump but the System Type (Installer
Setup Number 0172) is set to Heat
Pump.
Set System Type (Installer Setup Number 0172) to match
the installed heating and/or cooling equipment.
Heating and cooling wires are
shorted together.
Separate the shorted heating and cooling wires.
Heating equipment is running in
the cool mode.
Heating equipment is not a heat
pump but System Type (Installer
Setup Number 0172) is set to Heat
Pump.
Set System Type (Installer Setup Number 0172) to match
the installed heating and/or cooling equipment.
Heating equipment does not turn
off and heat temperature setting
is set below room temperature
(Heat On is not in the display).
Heating equipment is not a heat
pump but System Type (Installer
Setup Number 0172) is set to Heat
Pump.
Set System Type (Installer Setup Number 0172) to match
the installed heating and/or cooling equipment.
Cannot set the system setting to
Heat.
System Type (Installer Setup
Number 0172) is set to Cool Only.
Set System Type (Installer Setup Number 0172) to match
the installed heating and/or cooling equipment.
Cannot set the system setting to
Cool.
System Type (Installer Setup
Number 0172) is set to Heat Only or
Heat Only with Fan.
Set System Type (Installer Setup Number 0172) to match
the installed heating and/or cooling equipment.
Table 15. Troubleshooting. (Continued)
Symptom
Possible Cause
Action
