Page 17
NOTE-Contactor K1 is energized by the thermostat control system. Depending on the control system installed, the contactors may or may not be immediately energized upon demand. Refer to the operation se quence for the control system installed. Page 17...
Page 27
NOTE-If owner complains of insufficient cooling, the unit should be gauged and refrigerant charge checked. NOTE-The following is a generalized procedure and does not apply to all thermostat control systems. Elec tronic and ramping thermostat control systems may op erate differently. Refer to the operation sequence sec tion of this manual for more information.
Page 28
Make sure thermometer wells are filled with oil be fore checking. IMPORTANT - Block compressor compartment with access panel so air will not by-pass the coils. NOTE-The following is a generalized procedure and does not apply to all thermostat control systems. Page 28...
Page 29
NOTE-Tension new belt after 24-48 hours of operation. This will allow belts to stretch and seat in grooves. To increase belt tension, loosen two locking bolts and pull mounting plate. Tighten motor mounting plate in verti cal position. NOTE-Filters must be U.L.C. certified or equivalent for use in Canada.
Page 36
T2 TRANSFORMER RATINGS Electric Heat Internal Secondary Primary Unit Fuse 50VA 208/230V Red Tap 208V Blue Tap 24VAC Exc. 75kW Orange Tap 230V 2.5A Yellow Tap Common Black Tap Common 70 VA Red Tap 208V 208/230V Blue Tap 24VAC Orange Tap 230V 75kW 3.5A Yellow Tap Common...
Page 37
Contactor K17 Contactor K16 1st Stage Heat Demand Contactor K18 3rd Stage 2nd Stage Contactor K15 Pilot Relay K9 4th Stage (40kW and 50 kW 1st Stage (all units) (208/230v 30kW and 2nd Stage Heat Demand (50 kW 208/230v units) 208/230V units only) all 40 kW &...
Page 38
Contactor K17 Contactor K16 3rd Stage 2nd Stage Contactor K15 Contactor K18 (45kW and 60kW (208/230v 30kW and 1st Stage (all units) 4th Stage 208/230V units only) all 45kW and 60kW units) (60kW 208/230V only) Primary Limit S15 (208/230V only) Redundant Limit S63 (460 &...
Page 39
5th Stage Heat Electric Heat 1st Stage Heat Demand 2nd Stage Heat Demand Contactor K75 Transformer T2 Pilot Relay K9 Pilot Relay K19 75kW Only 5th Stage Heat K9 K19 Fuse F3 75kW Only 4th Stage Heat DL18 Time Delay DL18 4th Stage Heat Fuse F3 75kW Only...
Page 41
REMD16M-185 (horizontal application) CHA16 1853 Unit Outdoor Air Dampers Air Filters Return Air Duct Gravity Exhaust Dampers REMD16M-185 (downflow application) Outdoor CHA16-1853 unit Air Dampers Air Filters Gravity Exhaust Dampers Optional Power Exhaust Dampers Page 41...
Page 44
If the enthalpy control is set at setpoint A" as shown in figure 45, the following situation could occur.A cooling demand when the outside air is at 75 and 20 percent humidity would drive the economizer outdoor air dampers open to utilize outdoor air for cooling.The compressor cooling circuit would be disabled.Howev er, if the outdoor air should change to 70 F (a drop in temperature) and 70 percent humidity (a dramatic rise...
Page 48
NOTE- See CAUTION. Compressor monitor (Low Ambient Lockout Switch) S3 cannot be used with optional low ambient kit.Com pressor monitor MUST be disconnected before allow ing low ambient kit to be used. Electrical shock hazard. Low ambient kit wiring changes depending on unit size. Depending on the application, low ambient controls may be wired to low voltage or line voltage.
Page 50
Jack J25 / (opt. Plug P25) (used in 15 ton and larger units only) Jack J2 / (opt. Plug P2) Jack J33 / (opt. Plug P34) (used in 15 ton and larger units only) Jack J35 / Plug P35 (used in 12.5 ton and smaller units only) Jack J3 / Plug P3 Jack J36 / Plug P36 (used in 15 ton and larger units only)
Page 51
D5 Wiring Diagram - Modulating Economizer Model Number REMD16M-185 Warm-Up Kit Page 51...
Page 53
July 1989 and is not shown in the CHA16-1853. However, Flexstat remains a valid matchup to commercial CHA16 units of all sizes until inventories are depleted. You may find some CHA16-1853 units using it.
Page 54
C14-1 Wiring Diagram C8 1 diagram C12 Wiring Diagram C8-1 Wiring Diagram C12-2 Wiring Diagram *NOTE-Some clocks may be 120VAC while most are 24VAC. Be sure to check clock motor rating and wire clock according to its rating. Page 54...
Page 56
C1 diagram with B9 and A16 diagrams basic thermostat with CHA16 1853, with typical electric heat and without economizer...
Page 58
C1 diagram with D5 diagram electromechanical thermostat with modulating economizer...
Page 59
NOTE-In this operation sequence the unit diagram has been omitted in order to concen trate on the interaction between thermostat and economizer. NOTE-Relay K9 is part of the ECH16 electric heater used with the CHA16 unit for heating. NOTE-K11 relay is part of the REMD16M 185 economizer.
Page 60
C2-1 diagram with D5 diagram electromechanical thermostat with modulating economizer and warm-up...
Page 61
1 - The warm-up kit requires the use of optional time clock CMC3-1. 2 - Optional night thermostat S12 must be installed. 3 - The warm-up kit can only be installed in CHA16 units with REMD16 economizer. NOTE-This operation sequence emphasizes warm up kit operation. Unit diagram has...