Jack BIG BJ90 Owner's Manual - page 16
16
SERVICE HINTS
Main blower vibrating when in use...
POSSIBLE CAUSE
Loose allen screw on squirrel cage
Bad motor bearings
Weight on squirrel cage wheel moved in shipment
Main blower or blowers continue to run...
POSSIBLE CAUSE
Fan limit control on unit is set too low
Bad fan limit control
Improper wiring
Main blower or blowers won’t turn on...
POSSIBLE CAUSE
Improper wiring
Bad fan limit control
Combustion blower staying on...
POSSIBLE CAUSE
Wall thermostat bad, check by turning temp. to 60º then check
if draft blower is running
Short in thermostat wire
Home is not getting heat needed to satisfy wall thermostat
Combustion blower not turning on...
POSSIBLE CAUSE
Switch on blower to the off position. Bad wall thermostat;
check by turning it up to 80º and if the draft blower does not
turn on, replace thermostat
Limit control open
Smell an odor from the first fire in the home...
POSSIBLE CAUSE
New steel, small amounts of residue on steel
SOLUTION
Tighten the allen screw, be sure squirrel cage did not move to one
side or the other.
Return blower for a replacement.
Try to adjust it or return blower for replacement.
SOLUTION
Remove cover on fan limit control and set dials to the proper set-
tings. Recommended temps: 160º on — 130º off. NOTE: Never
adjust fan limit by turning dial itself (picture of fan limit dials.)
Check by turning one pointer down to where blower should turn
off, if they don’t, they need to be replaced.
Go over wiring diagram again.
SOLUTION
Go over wiring diagram again.
Replace fan limit control with a new one.
SOLUTION
Replace wall thermostat.
Check all wiring again.
Check on spec’s chart to be sure your unit is large enough for your
home. Be sure installation is proper, check with your local heating
service provider.
SOLUTION
Replace thermostat.
Check, then repair or replace.
SOLUTION
This will disappear in a matter of hours.