Honeywell T7351F2010 - Digital Thermostat, 3h Installation Instructions Manual page 13

Symptom
Heat will not No power to the thermostat. Check that X terminal is connected to the system transformer.
come on.
Thermostat minimum off
time is activated.
System selection is set to
Off or Cool.
Cooling will not No power to the thermostat. Check that X terminal is connected to the system transformer.
come on.
Thermostat minimum off
time is activated.
System selection is set to
Off or Heat.
System indicator The call for heat or cool is
(flame: heat, not yet given.
snowflake: cool)
is displayed, but
Conventional heating
no warm or cool
equipment turns the fan on
air is coming
only after the furnace has
from the
warmed to a setpoint.
registers.
Heating or cooling
equipment is not operating.
Table 7. Troubleshooting Information. (Continued)
Possible Cause
T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT
Check for 24 Vac between X and RH terminals.
If missing 24 Vac:
• Check if circuit breaker is tripped; if so, reset circuit breaker.
• Check if system fuse is blown; if so, replace fuse.
• Check if the HVAC equipment power switch is in the Off position; if
so, set to the On position.
• Check wiring between thermostat and HVAC equipment. Replace
broken wires and tighten loose connections.
If 24 Vac is present, proceed with troubleshooting.
• Wait up to five minutes for the system to respond.
• Configure heating response.
Set system selection to Heat or Auto.
Check for 24 Vac between X and RH terminals.
If missing 24 Vac:
• Check if circuit breaker is tripped; if so, reset circuit breaker.
• Check if system fuse is blown; if so, replace fuse.
• Check if the HVAC equipment power switch is in the Off position; if
so, set to the On position.
• Check wiring between thermostat and HVAC equipment. Replace
broken wires and tighten loose connections.
If 24 Vac is present, proceed with troubleshooting.
• Wait up to five minutes for the system to respond.
• Configure cooling response.
Set system selection to Cool or Auto.
Check if any stage indicators (dots next to the system indicator) are
displayed. With no display of stage indicators, no call for cool/heat is
yet given.
Wait one minute after seeing the on indicator and then check the
registers.
Verify operation of heating or cooling equipment in self-test.
13
Action
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