Page 27
Laars Sequencing Controls
There are more than one green lead stage lights on
Check the 120VAC power input to the SC. Turn power to the SC off and back on. If only one lead stage LED does not light, the
unit may be damaged.
Lead Stage does not rotate when switch to
INCREMENT
Only units which have (all stages of) their
OFF/AUTO/ON
switches in the
OFF/AUTO/ON
OFF/AUTO/ON
AUTO
position and which are designated as Unit or
Lo stages (see chart on pg. 19) can be lead. If there is more than one stage which meets this criteria, the SC may be damaged.
Lead Stage does not rotate every 24 hours (First On/Last Off Rotation)
Check the dip switch is set up for First On/Last Off rotation (see pg. 4). Check the lead stage can be rotated as described above.
Finally, check if the
INCREMENT/OFF/AUTO
switch is in the
AUTO
position. In the
AUTO
position, the lead stage should
rotate among the possible lead stages every 12 hours after the unit is fi rst powered up, and then every 24 hours thereafter. If the
panel loses power, the lead stage and the rotation counters will be reset.
Lead Stage does not rotate First On/First Off
Check the dip switch is set up for First On/First Off rotation (see pg. 4). Check the lead stage can be rotated as described above.
Finally check if the
INCREMENT/OFF/AUTO
switch is in the
AUTO
position.
STAGE OUTPUTS
When switched to
ON
, the unit does not come on
Remove any wires attached to the SC output. Check for continuity across the SC N.O. contacts. If there is continuity, the SC
output is working correctly. Check the wiring and the unit being energized to determine why it is not operating.
Red stage light is lit, but the unit is not on
The SC is calling for this unit to be on. Follow the procedure above.
Red stage light is not lit, but the unit is on
SC N.O. contacts. If there is no continuity, the SC output is working correctly. Check the unit for any other operating controls
which may be causing it to run.
Stage Outputs don’t Sequence
Make sure that the red output lights on the SC correspond to the stage’s operation. If they don’t, follow the steps above.
temperature is correct and the display does not read
OFF
or
PrF
. Finally, check the
OFF/AUTO/ON
stage switches. Only
OFF/AUTO/ON
OFF/AUTO/ON
units which (have all stages) switched to
AUTO
will be part of the automatic Sequencing.
SYSTEM OUTPUT
When switched to
ON
, the
SYSTEM
component does not come on
SYSTEM
SYSTEM
Remove any wires attached to the SC
SYSTEM
terminals. Check for continuity across the N.O. contacts. Then check the
N.C. terminals are open. If both are true, the SC is working correctly. Check the wiring and the component being energized to
determine why it is not operating.
Red stage light is lit, but the
SYSTEM
component is not on
SYSTEM
SYSTEM
The SC is calling for the unit. Follow the procedure above.
Red stage light is not lit, but the
SYSTEM
component is on
SYSTEM
SYSTEM
The SC is not calling for the unit to run. Remove any wires attached to the SC
SYSTEM
output terminals. Check the N.O.
SYSTEM
SYSTEM
terminals are open. Then check the N.C. terminals are closed. If both conditions are true, the SC output is working correctly.
Check the unit for any other operating controls which may be causing it to energize.
