10902 17TH PL W 2025-01-06 - Laserfiche WebLink

13. Supplementary resistance heat, if installed, should now 6. Loss Of Charge Protector- The control opens from its come on. Make sure it is operating correctly. If outdoor normally closed position to open the compressor contactor thermostats are installed, the outdoor ambient must be should the system lose its refrigerant charge. below the set point of these thermostats for heaters to 7 Outdoor Thermostats-These optional controls are used operate. It may be necessary to jumper these thermo- to prevent full electric heater operation at varying outdoor stats to check heater operation if outdoor ambient is mild. ambient (-17.8 to 7.2°C). They are normally open above 14. For thermostats with emergency heat switch, return to their set points and closed below to permit staging of in- startup (item#9). The emergency heat switch is located door supplemental heater operation. at the bottom of the thermostat. Move this switch to emer- 8 Reversing Valve Coil -This coil is activated by the ther- gency heat. The heat pump will stop, the indoor blower mostat (system switch) during cooling only and during will continue to run, all heaters will come on and the ther- defrost. It positions the reversing valve pilot valve for cool- mostat emergency heat light will come on. ing operation. 15. If checking the unit on the heating cycle in the winter- time,when the outdoor coil is cold enough to actuate the OPERATION: defrost control,observe at least one defrost cycle to make In operation the power to the circuit board is controlled by a sure the unit defrosts properly. temperature sensor which is clamped to a return bend on the 16. Check to see if all supply and return air grilles are ad- outdoor coil.Timing periods of 30, 60, or 90 minutes may be justed and air distribution system is balanced for the best selected by connecting the circuit board jumper wire to 30, compromise between heating and cooling. 60, 90 respectively. 17. Check for air leaks in the ductwork. Accumulation of time for the timing period selected starts 18. Make sure the heat pump is free of"rattles", and the tub- when the sensor closes(approximately-2.2°C)and when the ing in the unit is free from excessive vibration.Also make wall thermostat is calling for heat.Atthe end of the timing period, sure lines are not rubbing against each other or sheet a defrost cycle will be initiated provided the sensor remains metal surfaces or edges. If so, correct the trouble. closed. 19. Set thermostat at the appropriate setting for cooling and When the sensor opens (approximately 18.30C), the defrost heating or automatic changeover for normal use. cycle is terminated. If the defrost cycle is not terminated due to 20. Be sure the owner is instructed on the unit operation, the sensor temperature, a 10 minute override interrupts the filter servicing, correct thermostat operation, etc. defrost period. SUGGESTED FIELD TESTING /TROUBLE SHOOTING The foregoing"Start-up Procedure and Check List"is recom- mended to serve as an indication that the heat pump system A. Run unit in heat mode. will operate normally. B. Check unit for proper charge. Note: Bands of frost indi- COMPONENTS: cate low refrigerant charge 1. Contactor-This control is activated (closed)by the room C. Shut off power to unit. t-stat for both heating and cooling. It is de-energized(open) D. Disconnect outdoor fan by removing the purple lead from during emergency heat. The contactor has a 24 volt coil "DF2" on defrost control. and supplies power to the compressor and outdoor fan motor. E. Restart unit and allow frost to accumulate. 2. Crankcase Heater - This item is on whenever power is F. After a few minutes of operation,the defrost thermostat supplied to the outdoor unit. It warms the compressor should close. To verify this, check for 24 volts between crankcase, thereby preventing liquid migration and sub- "DFT" and "C" on board. If the temperature at the ther- sequent compressor damage. It is connected electrically mostat is less than -2.2°C and the thermostat is open, to the contactor L1 and L2 terminals. replace the thermostat as it is defective. 3. Condenser motor-The condenser motor is activated by G. When the defrost thermostat has closed,short the"test" the contactor during heating and cooling except during pins on the board until the reversing valve shifts, indi- defrost and emergency heat operation. cating defrost. This could take up to 21 seconds de- pending on what timing period the board is set on.After 4. Compressor-This item is activated by the contactor for defrost initiation,the short must instantly be removed or heating and cooling except during emergency heat. It is the defrost period will only last 2.3 seconds. protected by an internal overload. H. After the defrost has terminated, check the defrost ther- 5. Defrost Control-The defrost control provides time/tem- perature initiation and termination of the defrost cycle. should indicate 0 volts (open sensor). 9 Downloaded from www.Manualslib.com manuals search engine