COMPLIANCE INFO_PRE 2019 - Laserfiche WebLink

Home Browse Search

E TYPE III CERTIFICATION Technicians maintaining, servicing, repairing or disposing of low-pressure appliances must be certified as a Type III Technician or a Universal Technician. As of November 14, 1994, the sale of CFC and HCFC refrigerants is restricted to certified technicians. NOTE: If EPA regulations change after the technician is certified, it will be the technician's responsibility to comply with any future changes. LEAK DETECTION Because a low-pressure system operates below atmospheric pressure (in a vacuum), leaks in the gaskets or fittings will cause air and moisture to enter the system. The most efficient method of leak checking a charged low-pressure refrigeration unit is to pressurize the system by the use of controlled hot water or heater blankets. When controlled hot water or heater blankets are not feasible, use nitrogen to increase pressure. When pressurizing a system, do not exceed 10 psig. Exceeding 10 psig can cause the rupture disc to fail. When leak testing a water box, be certain the water has been removed before placing the leak detector probe through the drain valve. To leak test a tube, use a hydrostatic tube test kit. Systems with open drive compressors are prone to leaks at the shaft seal. Controlled hot water can be used to pressurize a system for the purpose of opening the system for a non -major repair. Under EPA regulations, a "major repair" means any maintenance, service or repair involving the removal of any or all of the following components: the compressor, the condenser, the evaporator or any auxiliary heat exchanger coil. LEAK REPAIR REQUIREMENTS EPA regulations require that all comfort cooling appliances containing more than 50 lbs. of refrigerant be repaired when the annual leak rate exceeds 15%. EPA regulations require that all commercial and industrial process refrigeration containing more than 50 lbs. of refrigerant be repaired when the annual leak rate exceeds 35%. (See Type II for definition of commercial and industrial appliances.) RECOVERY TECHNIQUES A recovery unit's high pressure cut-out is set for 10 psig when evacuating the refrigerant from a low-pressure chiller and a rupture disc on a low-pressure recovery vessel relieves at 15 psig. Refrigerant recovery from a system using R-11 or R-123 starts with liquid removal and is followed by vapor recovery. A substantial amount of vapor will remain in the appliance after all liquid is removed. For instance, an average 350 ton R-1 I chiller at 0 psig still contains 100 lbs. of vapor after all the liquid has been removed. Water must be circulated through the tubes when evacuating refrigerant in order to prevent freezing the water. Most low- pressure recovery machines utilize a water-cooled condenser that is connected to the municipal water supply. When recovering refrigerant, the system water pumps, the recovery compressor, and the recovery condenser water should all be on. If a chiller is suspected of tube leaks, the water sides of the evaporator and condenser should be drained prior to recovering the refrigerant. The ASHRAE Guideline 3-1996 states that if the pressure in a system rises from 1 mm Hg to a level above 2.5 mm Hg during vacuum testing, the system should be leak checked. A temperature of 130° F should be attained when removing oil from a low-pressure system. Fewer refrigerants is contained in the oil at this higher temperature. RECHARGING TECHNIQUES Refrigerant is added through the lowest access point on the system, the evaporator charging valve. However, introducing liquid refrigerant into a deep vacuum will cause the refrigerant to boil and may lower temperatures enough to freeze water in the tubes. Therefore, initial charging is in the vapor phase. Before charging with liquid, an requires a vapor pressureRf 1�.9" hg. vacuum, or a saturation temperature of 36° F. FIE MAY 18 2015 ENVIRONMENTAL 4FAITW nr:Pa RTAAFNT