valutazioni - 2, GPA: 4.5
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Facilità d'uso
(Yellow-to-yellow and black-to-red.) CONNECT CONTROL POWER WIRING (24-v) — Power leads are brought thru 1 / 2-in. hole provided in unit, Fig. 1. Extend leads to low-voltage terminal board located on top of control box, Fig. 5. Connect leads to terminal board as shown in Fig. 3. Use room thermostat HH01AD042 and thermostat subbase HH93AZ044 for proper unit operation. Be sure that field-installed jumper wire is connected between subbase terminals W and Y. Set thermostat heat anticipator at 0.45 amp for 1-phase units and 0.50 amp for 3-phase units. START-UP Water Flow and Temperature Data 1. Consider design water flow rates for efficient operation. See Table 4 for permissible water flow range. 3. Ensure that supply water is clean and air is purged from system. Air in supply water causes scaling in heat exchanger. Foreign material in water and/or excessive velocity of water can cause damage to tubing. 4. When using a semi-closed system with an “open” cooling tower, a water treatment system should be operational with initial water flow. To Start Unit — Ensure that air filter is in place on unit filter flanges provided. Do not operate unit without filter in place. Adjust the thermostat as follows: 1. Set selector switch at OFF. 2. Turn on main disconnect switch to unit. 3. Set fan switch as desired (ON or AUTO.). 4. Set thermostat dial at desired temperature. 5. Set selector switch at HEAT or COOL. Check system refrigerant charge. See Refrigerant Charging on page 6. -^Unit Single-Phase Compressors that are equipped with a compressor start thermistor (PTC device) — When supply voltage is within limits indicated on nameplate and compressor will not start, check the thermistor with an ohmmeter. If the PTC is good, and the compressor does not start, disconnect the PTC from the starting circuit and give unit a temporary capacitance boost. Refer to Carrier Standard Service Techniques Manual, Chapter 2, for details on capacitance boost procedure. If unit does not start with capacitance boost, compressor may be defective. If unit does not start, check starting capability with PTC assistance. If questionable, remove PTC, add start capacitor and start relay per start kit installation instructions. WARN IN Gc Capaciiaace boost or iastalatioa of start capacitor and start relay should be per-fosraaed by irasasd persosaet Improper procedure coukf came pejsojiai mjary or equipuseat damage. Unit Controls and Safety Devices HIGH-PRESSURE RELIEF VALVE (except 50WQ014) is located in compressor. Relief valve opens at a pressure differential of approximately 550 psi between suction (low side) and discharge (high side) to allow pressure equalization. 4 CURRENT AND TEMPERATURE SENSITIVE OVERLOAD (linebreak) internal on all compressors except on 50WQ014 which has external shell mounted overload. Overload resets automatically when internal compressor motor temperature drops to a safe level (overloads may require up to 45 minutes to reset). When an internal overload is suspected of being open, check by using an ohm-meter or continuity tester. If necessary, refer to Carrier Standard Service Techniques Manual, Chapter 2, for complete instructions. HIGH-PRESSURE SWITCH opens and shuts compressor off if discharge pressure rises above 395 psig. Switch closes at 295 psig. FREEZE-UP PROTECTION — Two controls are used to prevent unit from operating if water approaches freezing temperature during heating cycle. -»1. Low Water Temperature Cutout (LWTC) — shuts unit off and energizes lockout relay if water temperature reaches 37 F. 2. Lockout Relay — locks itself in energized position and prevents unit from starting. The unit can be restored to heating operation if the water temperature rises to 42 F, where the LWTC will reset, and if the thermostat circuit is interrupted either by lowering the thermostat setting or by moving system switch to OFF or COOL. Thermostat may then be readjusted to normal set point. -»HEAT PUMP CIRCUITS shown in Fig. 4 are refrigerant and water flow diagrams for heating and cooling cycles. Schrader service port located between the reversing valve and the heat exchanger permits field installation of swivel tee (Carrier Part No. DD44CA051) for connecting water regulating valves without losing refrigerant charge. -»WATER REGULATING VALVES control water flow to yield optimum performance in both the heating and cooling modes. In cooling, the controlling valve is actuated by head pressure. As the head increases, the valve opens and allows more water to flow. If the supply water is very cold, the head pressure will drop, causing the valve to throttle back. In heating, the direct-acting valve is closed due to very low pressure. The other valve is reverse-acting and opens on a drop in suction pressure. If the water temperature drops, the suction pressure will also drop causing the valve to open. This allows more water to flow, thereby preventing freeze-up. It also throttles back if the inlet water tem...