Issue link: http://read.uberflip.com/i/1376344
42 / MAY.JUNE.2021 USICERINKS.COM KEEP Refrigerated Refrigerated a licensed refrigeration contractor to have this work done. The proper annual shut- down of the system will include procedures for closing valves, disconnecting electrical circuits, the shutdown and maintenance of equipment related to primary and second- ary refrigerant circuits and required com- pressor maintenance, plus checks on the condenser and related equipment. A number of valves in the refrigeration plant will be closed during the shutdown period. Any valves that must be closed should be clearly tagged in accordance with established lock and tag procedures, with a notice to this effect being attached to the main panel disconnect switch. Control switches for all compressors, brine/glycol pumps and condenser fans and pumps should be turned off and tagged. The main electrical disconnect switch for the entire system should then be switched off and clearly tagged as well. As an additional precaution, fuses may be removed from the panel. In systems with multiple compressors, each compressor will have the suction and discharge service valves closed during the annual shutdown in order to isolate each one for servicing. If so equipped, the valve on the oil return line should also be closed. In addition, any primary refrigerant left in the crankcase must be purged, using proper safety procedures for that particular refrigerant, before the compressor can be opened. When consid- ering compressor maintenance during the shutdown period, reference must be made to the manufacturer's recommendations. Usually, on a reciprocating compressor (screws may be different) the number of hours a compressor runs during any given season will determine the extent of neces- sary maintenance. When the compres- sor is opened for an internal inspection, all parts should be thoroughly checked and replaced where necessary and any additional wear investigated. Regardless of the need for replacement of internal compressor parts, the crankcase oil should be changed more frequently, ensuring that the interior of the crankcase is well flushed out prior to recharging with clean oil. A sample of the used oil from each com- pressor should be analyzed annually to help determine the wear on internal parts. Upon completion of any repair work, the compressor(s) should be closed up and filled to the correct level with oil that is compatible with the primary refrigerant. With respect to the secondary refrig- erant equipment, the brine/glycol stop valves should remain open during the shutdown period to prevent hydraulic pressure damage due to expansion as the brine/glycol warms up. The rink floor piping, headers and brine/glycol lines should not be isolated from the brine/glycol expansion tank for the same reason. If using brine as the secondary refrigerant, the pump should be rotated at least once a month during shutdown to break up any calcium depos- its that may damage pump seals. Bearings and valve stems should be greased. As well, bypass filters on the brine/glycol system should be cleaned or the filter replaced. Header pipes should be inspected for corrosion and loose hose clamps. The level of brine/glycol in the expansion tank should be checked and recorded. Once a year, a sample of brine/ It cannot be stated strongly enough that any maintenance work done on refrigeration equipment must be performed by properly qualified personnel following the manufacturer's recommendations.