Friedrich YL24J35A, Service & Parts Manual

Page: 34 / 62

TTJ-0198 (10/97) (Page 34 of 64)
PROBLEM POSSIBLE CAUSE TO CORRECT
Disconnect power to unit. Remove resistor
from thermostat bulb block. Plug in unit and
allow to operate. Feel resistor for heat. If no
heat is felt, replace resistor.
Replace thermostat and check operation.
Fan operates –
heating element
does not
come on.
Heater relay or contactor coil open.
Heater relay or contactor stuck open,
pitted or burned.
High limit control open.
Open thermal fuse.
Open or shorted element.
Loose connections.
Check continuity of coil.
Inspect, test continuity with ohmmeter.
Check continuity – if open, replace.
Check continuity. Check reason for failure.
Check voltage across heater terminals. Check
amperage draw of heater.
Tighten all terminals.
PROBLEM POSSIBLE CAUSE TO CORRECT
Restricted filter.
Cycling high limit control.
Exhaust or fresh air door open.
Heating
inadequate.
Clean as recommended in Owner’s Manual.
Control is set to open at 155
° F ± 5 ° F and close
at 130°F ± 8°F. If cycling prematurely, replace
control.
Check position of fresh air door control slide.
Adjust cable if door does not close properly.
PROBLEM POSSIBLE CAUSE TO CORRECT
Fan operates in
"Constant" position,
but not in
"Automatic"
(MoneySaver).
Fan relay contacts open.
Inoperative system switch.
Loose connection.
Check continuity of fan relay. NOTE: Some
models have the fan relay energized during the
heating cycle while others do not.
Check continuity between terminals "L2" and
"3" of the system switch.
Check connections on system switch and fan ’
relay.
PROBLEM POSSIBLE CAUSE TO CORRECT
Long "off" and "on"
cycles.
Heat anticipator (resistor) shorted.
Defective thermostat.