【Mechanical Equipment Technology Edition】Daily Question 201801023: Common Faults in Refrigeration Systems (8.1)
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This post was last edited by YORK Industrial Refrigeration on 2018-1-25 at 08:16. Starting from now, in order to enhance communication among users, a 【Daily Question】 activity has been launched on the Mechanical Equipment Technology forum. We hope everyone will participate actively to progress and improve together! ! ! Rewards: 3 wealth points for active participation, 10-15 wealth points for correct answers. This question is valid for two days; no score will be assigned after that time. There is a compressor whose exhaust temperature is too high. Currently, there are three possible explanations: 1) insufficient refrigerant, 2) poor cooling of the condenser, 3) problems with the expansion valve. How can the exact cause be determined? The elimination method can be used. There is a shortage of refrigerant; by comparing with normal parameters, the cooling rate is slower when the system is under full load, and the pressure is lower than usual. The condenser can be identified by a small temperature difference or by removing the end caps. Excluding the above two, the issue lies with the expansion valve ============================== High-quality promotions: Mechanical equipment——York screw compressors: Maintenance procedures https://bbs.hcbbs.com/thread-1806833-1-1.html Mechanical equipment——Upgrading York Quinton control centers https://bbs.hcbbs.com/thread-1804837-1-1.html Mechanical equipment——GEA Grasso screw compressors: Major repairs https://bbs.hcbbs.com/thread-1800467-1-1.html Mechanical equipment——British HOWDEN screw compressors: Disassembly and maintenance https://bbs.hcbbs.com/thread-1832529-1-1.html Mechanical equipment——Japanese Maekawa MYCOM screw compressors: Disassembly and maintenance https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=
There is a compressor whose exhaust temperature is too high. Currently, there are three possible explanations: 1. Insufficient refrigerant: The load cannot be increased; if the liquid levels in the evaporator and economizer are low, it may be due to a lack of refrigerant； 2. Poor cooling of the condenser: Conduct tests by changing the load; if there is no significant change, the cooler is fouled ； 3. Expansion valve issue: No change regardless of adjustments; the expansion valve must be suspected.
Check the amount of refrigerant and measure the return temperature of the circulating water
Bonus question: Is the filter clogged? Is the flow rate of the water being cooled too high in terms of process requirements? When such problems occur, the first thing to do is to try to resolve them as best as possible; for example, check whether the cooling water filter of the condenser is clogged, and see if gas is present in the supply/return pipes leading to the evaporator (test this by temporarily switching the flow). As a final step, shutdown the system for testing.
1. Insufficient refrigerant. By analyzing the composition of the refrigerant through testing, it is possible to determine that there is a shortage of refrigerant. 2. The condenser does not cool well. It is possible to determine whether there is a problem with the cooler by checking the pressure difference at its inlet and outlet, as well as the temperature difference between these two points. If neither of these two is the case, then it’s a problem with the expansion valve.
Refrigerant level or pressure. Condenser temperature difference detection: expansion valve position, temperature difference before and after, or flow rate.
1. Insufficient refrigerant: The load cannot be increased; after loading, the pressure change is minimal. 2. Poor cooling of the condenser: The temperature difference between the inlet and outlet water is incorrect. 3. Expansion valve issue: No change regardless of adjustments; the expansion valve must be suspected.
2. It is possible that the condenser is not cooling properly. 1 and 3 are not visible.