Coleman P-LBX16F14501 Installation Instructions Manual page 22

Table C-3: System and General Troubleshooting
Problem
Supply air temperature
too hot.
Supply air temperature
too cool.
Supply air temperature
too cool during first
moments of furnace
cycle.
22
continued
Possible Cause
Airflow blocked or dirty air
filter.
Insufficient airflow.
Excess airflow.
Excessive duct losses.
Fan control "fan on" setting too
low.
Excessive duct losses.
Clean or replace air filter.
Check all dampers. Open closed dampers including registers in
unused rooms. Check system temperature rise. If temperature
rise is too high, speed up blower fan.
Check system temperature rise. Slow down blower fan if
necessary.
Check supply air ductwork. Seal leaky joints and seams.
Insulate ductwork if necessary.
Increase differential between fan control "fan off" and "fan on"
settings. (L4064B, L6064A fan / limit controls only, no
adjustments available for L4064W fan / limit control). Register
air deflectors may help.
Check supply air ductwork. Seal leaky joints and seams.
Insulate ductwork if necessary.
Remedy