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Table 2 — Light Commercial Thermidistat (LCT) Operating Sequence and System Response
LEGEND
*Unless unit compressor has been rewired as described in Step 11 (page 29).
UNOCCUPIED
COOLING ER Comp ER Fans RT Comp 1 RT Comp 2 RT Fans RT Heat
Indoor Temperature Above 2nd Stage
Set Point
Humidity Low & OAT Low
On On (cyc.) On w/o MM Off On (cyc.) Off
Humidity Low & OAT High
Off Off On w/o MM w/o MM On (cyc.) Off
Humidity High & OAT Low
Off Off On w MM On w MM On (cyc.) Off
Humidity High & OAT High
Off Off On w MM On w MM On (cyc.) Off
Indoor Temperature Between 1st and
2nd Stage Set Points
Humidity Low & OAT Low
Off On (cyc.) Off Off On (cyc.) Off
Humidity Low & OAT High
Off Off On w/o MM Off On (cyc.) Off
Humidity High & OAT Low
Off Off On w MM Off On (cyc.) Off
Humidity High & OAT High
Off Off On w MM Off On (cyc.) Off
Indoor Temperature Below 1st Stage
Set Point
Off Off Off Off Off Off
NOTE: OAT < 55° all compression off*
HEATING ER Comp. ER Fans RT Comps. RT Fans RT Heat
Indoor Temperature Above 1st Set
Point
Off Off Off Off Off
Indoor Temperature Between 1st and
2nd Stage Set Points
Off Off Off On (cyc.) On, 50%
Indoor Temperature Below 2nd Stage
Set Point
Off Off Off On (cyc.) On, 100%
OCCUPIED
COOLING ER Comp ER Fans RT Comp 1 RT Comp 2 RT Fan RT Heat
Indoor Temperature Above 2nd Stage
Set Point
Humidity Low & OAT Low
On On On w/o MM On w/o MM On Off
Humidity Low & OAT High
On On On w/o MM On w/o MM On Off
Humidity High & OAT Low
On On On w MM On w MM On Off
Humidity High & OAT High
On On On w MM On w MM On Off
Indoor Temperature Between 1st and
2nd Stage Set Points
Humidity Low & OAT Low
Off On Off Off On Off
Humidity Low & OAT High
On On On w/o MM Off On Off
Humidity High & OAT Low
On On On w MM Off On Off
Humidity High & OAT High
On On On w MM Off On Off
Indoor Temperature Below 1st Stage
Set Point
Humidity Low
Off On Off Off On Off
Humidity High
On On Off Off On Off
NOTE: OAT < 55° all compression off*
HEATING ER Comp ER Fans RT Comps RT Fans RT Heat
Indoor Temperature Above 1st Stage
Set Point
Off On Off On Off
Indoor Temperature Between 1st and
2nd Stage Set Points
OAT >Set Pt
On On Off On Off
OAT <Set Pt
On On Off On On, 50%
Indoor Temperature Below 2nd Stage
Set Point
OAT >Set Pt
On On Off On On, 50%
OAT <Set Pt
On On Off On On, 100%
Comp —
Compressor
ER —
Energy Recovery section
MM —
MoistureMi$er™ Dehumidification Device
OAT —
Outdoor-Air Temperature
RT —
Rooftop Unit
Set Pt —
Set Point