t
SYMPTOMS
POSSIBLE CAUSES
CHECK/REMEDIES
4.
Indoor temperature overrides
thermostat setting
Improper thermostat heat
anticipator setting
Adjust heat anticipator; add 100
Ohm, 10 watt resistor
Thermostat out of calibration;
thermostat not level
Calibrate according to thermostat
manufacturer's instructions;
Level thermostat subbase
Improper thermostat location
Relocate thermostat
5. Thermostat cuts off furnace
before indoor temperature
is obtained
Improper thermostat heat
anticipator setting
Adjust heat anticipator;
add 100 Ohm, 10 watt resister
Thermostat needs calibrating;
Subbase is not level
Calibrate according to thermostat
manufacturer's instructions;
level subbase
Improper thermostat location Relocate thermostat
6. Excessive blower operation Improper fan off delay setting Reset fan off delay setting on IFC
Limit tripped
Determine cause and correct
Blower motor overload open
Measure blower amp draw and
compare to nameplate amperage.
Replace motor if faulty
Low voltage Check voltage and correct
as needed
Loose electrical connections
Check and tighten any
loose connection
Inoperative integrated furnace control Replace
7. Excessive blower noise Blower wheel loose on motor shaft Tighten set screws
Blower running too fast
Check CFM, temperature rise,
and adjust as necessary
Duct vibration or undersized ducts
Check duct system and correct
Blower wheel dirty
Remove and clean
Damaged blower or unbalanced wheel
Repair or replace
Motor bearing worn Replace motor
Noisy blower motor Replace if necessary
Blower compartment door loose
Secure door
8. Air noise from register
Register too small or damper closed Determine CFM requirement and
size register accordingly or
adjust damper
Wrong register type
Replace as necessary
Air velocity too great
Reduce blower speed and/or
replace register
115
To Next Page
Loading...