Lang ECCO-AP, Service Manual

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41
TROUBLESHOOTING ECCO-C CONT’D
NO HEAT Manual Mode
NOTE: Fan must be operating before trouble shooting No heat.
PROBABLE CAUSE CORRECTIVE ACTION
Back-up relay not energizing
!
Check for 240 VAC on relay coil.
If 240 VAC is measured. Turn unit off and:
!
Check back-up relay coil for 7.2
Ω
.
!
Check “ NO ” contacts for 24 VAC.
!
Replace if defective.
If 240 VAC is not measured:
!
Check back-up switch (SPDT) for normal operation.
!
Replace if defective.
Defective thermostat
!
Turn unit off and check for continuity while cycling thermostat on
and off.
!
Replace if defective.
Defective contactor
!
Check for 24 VAC at heater coil.
If 24 VAC is measured. Turn oven off and:
!
Check for continuity through coil.
!
Replace if defective.
If 24 VAC is not measured.
Turn oven off and:
!
Check for continuity through hi-temp wires going to over-temp
thermostat.
!
Replace over-temp thermostat if defective.
Defective elements
!
Check elements for continuity.
!
Replace if defective.