START-UP
Never operate unit without a filter or with grille removed; damage to the unit or personal injury may result.
Make the following checks and complete the Start-Up Checklist on page CL-1 before system start-up. Also refer to the condensing unit Installation, Start-Up and Service Instruc- tions for system start-up instructions and refrigerant charging methods.
1.Check condensate drainage system:
a.Remove grille and frame from the unit.
b.On the opposite side of the drain connection, insert a water bottle up into the fan coil unit and fill drain pan. Refer to Fig. 22. Water must flow steadily; if not, check the pipe slope or inspect for any pipe restrictions.
2.Make sure that all wiring connections are correct and that they are tight.
3.Check that all barriers, covers, and panels are in place. Ensure that the filters and return-air grilles have been installed and that the discharge louvers are positioned correctly.
After Extended Shutdown — If the system has been turned off for more than 12 hours and a crankcase heater is be- ing used, turn on the indoor and outdoor unit disconnect switches to supply power to the system for 12 hours BEFORE starting the system.
Seasonal Changeovers — When changing heat pump system from cooling to heating or heating to cooling, or before starting cooling only system after it has been out of use for the winter season, perform the following steps BEFORE starting the system:
1.Inspect and clean the outdoor unit, particularly the coil.
2.Clean or replace the air filters in the indoor unit.
3.Clean the indoor unit drain pan and drain pipe, and remove any obstructions.
4.If the outdoor unit is equipped with a crankcase heater, turn on indoor and outdoor unit disconnect switches to supply power to the system 12 hours before starting the system.
Adjusting Airflow
AUTOMATIC AIR SWEEP — All units are equipped with an air sweep feature which directs the airflow louvers up and down to provide optimum room air circulation. The air sweep function can be controlled by the toggle switch located on the lower right corner of the unit. If using a thermostat with an air sweep switch, see Fig. 20 and 21 for wiring modifications.
Operating Mode Memory — After the system is turned off or after a power failure, the system remains in the last operating mode selected. When the system is turned back on, or when power is automatically restored, operation contin- ues in the same operating mode as when the system shut down.
Automatic Operation (Auto.) Mode — If auto. mode is selected, the system automatically switches over the operating mode from heating to cooling, or from cooling to heating (heat pump system only) depending on the selected temperature. Auto. mode also controls fan speed if not manual- ly overridden.
NOTE: Between the cooling cycle and the heating cycle there is a neutral zone of approximately 2° F above and 2° F below the selected temperature when only the fan is operating.
Operating Sequence — Ceiling-suspended fan coil units have a relay board which controls system operation in re- sponse to a room thermostat. The user may manually select any one of 3 fan speeds for unit operation. Ceiling-suspended sys- tems may be equipped with an accessory power ventilation kit and/or condensate pump.
FAN OPERATION — Fan coils are capable of 3-speed opera- tion. See thermostat instructions for fan speed selection. When the fan(s) is operating in medium or high speed and the unit is equipped with the power ventilation kit, the ventilation fan will operate to provide fresh air.
COOLING MODE OPERATION — When the room ther- mostat senses a demand for cooling, the fan coil relay board is energized. The indoor fan(s) will start in the selected speed (if it is not already operating). The reversing valve (heat pump only) will energize for cooling operation.
The internal condensate pump (if so equipped) runs when- ever the reversing valve is energized (heat pump only) and/or the unit is in cooling. As long as the condensate float switch and freeze protection thermostat are closed, the cooling relays in the fan coil unit will close. This energizes the compressor and outdoor fan in the outdoor unit. The compressor will con- tinue to operate until the room thermostat is satisfied. When the cooling demand is satisfied, the compressor and outdoor fan will stop. If the system is in the AUTO. position, the indoor fan will stop with the compressor. If the unit has the accessory ven- tilation kit, the ventilation fan will operate whenever the indoor fan is set for medium or high speed.
HEAT PUMP OPERATION — When the room thermostat senses a demand for heating the indoor fan will start in the selected speed (if not already operating), and the reversing valve will not be energized. The internal condensate pump (if supplied) and freeze protection thermostat are not operated during heating operation. The control relay (CR2) closes, and the compressor and outdoor fan are energized through the de- frost board (DFB), which is located in the outdoor unit. The microprocessor logic in the DFB is energized when the com- pressor starts, and the defrost timer runs. Once every 90 min- utes (factory default setting) of compressor run time, the DFB logic checks the defrost thermostat (DFT). If the DFT is open, the unit continues in heating operation. If the DFT is closed, the DFB switches the unit to defrost mode. The timing on the DFB may be set at either 30, 50, or 90 minutes.
DEFROST (Heat Pump Only) — The DFB energizes the RVS (reversing valve solenoid), and the reversing valve switches to the cooling position. The K1 relay on the DFB opens and the outdoor fan stops. The W2 contact on the DFB is also energized, which in turn energizes the defrost relay on the fan coil relay board, turns off the electric heater and stops the indoor fan.
The DFB logic checks the 10-minute defrost timer and the DFT. If the DFT opens in less than 10 minutes, the DFB switches the unit back to normal heating operation. If the DFT remains closed, the DFB switches the unit back to heating op- eration after 10 minutes. When the DFB changes back to heat- ing mode, the RVR (reversing valve relay) is deenergized and the reversing valve switches back to heating operation. Both the outdoor and indoor fans come back on, and if necessary, the electric heater also turns on.
SYSTEM SAFETIES — The system is equipped with the following safety devices to protect system components:
Indoor coil freeze protection thermostat — If a coil temper- ature of 28 F or lower is sensed, the compressor and outdoor fan will be shut down until the coil temperature exceeds 28 F. The indoor fan will continue to run.
Condensate float switch (units equipped with accessory condensate pump, cooling cycle only) — If the level of con- densate in the drain pan rises too high, the condensate float switch will turn the system off.
