All installations and services must be performed by qualified service personnel.
B.Cooling Section
1.Initial Startup:
: Refrigerant is under pressure. Guard against refrigerant spraying into the face or on skin. Always wear protective equipment, i.e. safety glasses or goggles and gloves when working with refrigerant.
: Do not under any circumstances heat the refrigerant cylinder with a torch or by any other means other than warm water. Excessive pressures generated in this manner may weaken the refrigerant container and result in an explosion!
On cool days (65°F or lower), attempts to operate the cooling section and take gauged pressure readings may be unsuccessful as unusually low pressure will be observed on the suction line. This type of operation may give the impression of an undercharged unit. This is not necessarily the case. A low refrigerant pressure reading may occur due to the combined action of the large condenser surface area and cold ambient air removing a large amount of heat from the refrigerant. As a result, subcooling of the refrigerant occurs and very low refrigerant pressures can be measured. Adding refrigerant in cold weather will result in an overcharged unit. During warm or hot weather, high ambient temperatures will greatly increase the refrigerant pressure which may then cause the high limit pressure switch to shutdown the unit. Due to the high probability of taking a false reading, suction line pressure should not be taken for test purposes when the outdoor temperature is below 70° F.
When the outdoor air temperature is cooler than the indoor air temperature, refrigerant vapor will condense in the compressor. If the compressor is started when it contains liquid refrigerant, the lubricating oil in the crankcase will be diluted. Bearing damage may result under these conditions.
The appliance is equipped with gauge ports to connect both liquid and suction line pressure gauges. These ports are located near the base of the unit, inside the burner compartment. Refrigerant hoses must be the types that incorporate a “finger” to depress the valve core. Connections may be made to these ports at any time, even while unit is in operation. Follow EPA guidelines in connecting service equipment to refrigerant lines. For example, using quick connects and short service hoses is recommended to minimize refrigerant losses.
Line pressures on an operating air conditioning unit will vary with outdoor temperatures. As outdoor temperatures rise, pressures will also rise. Refer to a
40
