Votos - 4, Puntuación media: 4.3 ( )

Fabricar: Bryant Tamaño del archivo: 1.39 mb Nombre del archivo: Idioma del manual:

The pilot flame then ignites the burners. The 821 heating blower relay (2G) was energized when the circuit through the thermostat was completed. After a short delay, the blower relay (2G) contacts close and the circuit to the blower motor (3D) is completed. This circuit energizes the motor to start the blower. When the thermostat is satisfied, the circuit between R and W within the thermostat will break. On units equipped with the glow-coil pilot, the circuit to gas valve (5A) is deenergized and gas flow to the burners is stopped. On units equipped with the RELITE pilot, the broken thermostat circuit deenergizes the pilot gas valve and gas flow to both the pilot and the burners is stopped. Heating blower relay (2G) is also deenergized. There will be a delay before the heating relay (2G) contacts open. When these contacts do open, the blower motor (3D) is deenergized. Both types (glow-coil or RELITE pilot) of units are now in a “standby” condition, waiting for the next “call for heat” from the thermostat. G. Limit Switch Operation The furnace limit switch (7K) functions to shut off gas and main burner operation if the furnace becomes overheated. See Figures 13 and 14. The limit switch is a temperature-actuated switch. Tbrminal No. 1 of the limit switch is a common terminal and is internally connected to the switch terminal No. 3 as long as the temperature at the limit switch is below 175° 5°F. When the temperature near the limit switch rises to 175° 5°F, switch terminal No. 3 is opened, and terminal No. 2 is now internally connected to switch terminal No. 1. This breaks the circuit to the gas valve (5A or 5D) and shuts off all gas supply to the burners. The control circuit is still closed to blower relay (2G) and the blower motor (3D) will continue to run as long as the temperature is above the limit setting. When the temperature at the limit switch drops to 130° 5°F, switch terminal No. 3 will again be internally connected to switch terminal No. 1. The gas valve will again be energized and supply gas to the burners. VIII. COOLING STARTUP AND ADJUSTMENTS CAUTION: Complete the steps in Section VII before starting unit. CAUTION: Do not jumper any safety devices when operating unit. A. Checking Components Perform the following steps before starting the unit. 1. Check for correct position of condenser fan blade in unit top panel. See Figure 3. 2. Leak-test all refrigerant circuit connections to make certain that none has been damaged in shipment. 3. Check entire system for leaks at all connections, including evaporator coil located in blower compartment. (Use electronic leak detector, halide torch, or liquid-soap solution.) NOTE: The cooling section is fully charged with refrigerant, tested, and factory-sealed. There should be no need to check refrigerant charge if no leaks were found. In rare instances, when the refrigerant charge may have been lost because of a leak caused by shipping or if a refrigerant leak has been found, proceed as follows: a. Locate and repair leak. WARNING: Never attempt to repair any soldered connection while system is under pressure. Severe bodily injury may result. b. Leak-test unit. c. Evacuate system. d. Charge unit with proper type and amount of refrigerant. CAUTION: The type and amount of refrigerant are listed on unit rating plate. It is recommended that a volumetric charging cylinder or an accurate scale be used when charging is necessary. Charge unit with exact amount of refrigerant as shown on unit rating plate. 4. Check to be sure all tools and loose parts have been removed. 5. Check to be sure all panels and covers are in place. Following this initial inspection, unit may be started. NOTE: Check three-phase evaporator blower motor for correct rotation. Direction of rotation is indicated by arrow on blower housing. If blower rotates in opposite direction, reverse any two blower motor leads or any two line-voltage leads. After leads are reversed, recheck blower rotation. B. Evaporator Airflow All 585A/YAC, 585A/YACR, and 586A/YACX units are equipped with direct-drive blower motors. Motor speeds have been factory-set for both heating and cooling to obtain optimum performance. See Tables VI and VII to determine airflow. On most units the motor speeds cannot be adjusted; however, some units do have unused speed taps that are available. See the unit wiring label. NOTE: Recommended evaporator airflow is 350 to 450 CFM per 12,000 Btuh of cooling. NOTE: Optional field-installed high-static blower packages are available for the 585A/YAC and 585A/YACR, sizes 036080 through 060150. Refer to Table VII to determine the airflow for these optional blowers. (Same as blowers used in equivalent sizes of the 586A/YACX.) C. Checking Unit Operation Perform the following steps to make certain the unit is operating properly: 1. Place thermostat system switch in COOL position; place FAN switch in AUTO position; set thermostat setting below room temperature. Observe th...

Descargar ahora

Introduzca dos números de la imagen: