Common fault judgment and analysis of thermal expansion of pneumatic valve

pneumatic valve by pneumatic valve body, thermal expansion pack, balance of pipe is by controlling the evaporator export the degree of superheat of refrigerant gas to control the flow of refrigerant entering the evaporator. As one of the four big cold cold water mechanism system, generally installed between the liquid storage container and evaporator, throttling depressurization and flow adjustment role. In the actual maintenance, some difficult problems of cooling system is difficult to quickly locate, often suspect is thermal expansion was replace pneumatic valve failure. Small make up with you about inflation today a common troubleshooting of pneumatic valve.
in the actual repair, if doubt expansion pneumatic valve has a problem, must first understand the status of the refrigeration system and peripheral components related to the work state, must not take expansion pneumatic valve operation from the start.
the fault one: expansion pneumatic valve provides the refrigerant flow is too big.
phenomenon: a liquid into the compressor; Low heat; Suction pressure is normal or slightly higher.
may cause analysis:
, thermal expansion pneumatic valve 'ice block', 'dirty', 'wax' etc, these conditions may make expansion pneumatic valve LiuKou fixed position in various possibilities, so may cause traffic is too big or too small.
, expansion of pneumatic valve port internal leakage and sealing is lax. If there is internal leakage, after the compressor stop at expansion pneumatic valve can still hear the flow of the 'hiss' sound, at the same time, see liquid from depending on the liquid lens is still in the flow. Observed from depending on the liquid mirror, of course, when the liquid flows, to eliminate the higher refrigerant backflow caused by interference and bubbles. After confirmed with internal leakage, can remove the LiuKou component inspection seal, if not solved, just need to change the whole pneumatic valve body.
, thermal package installation problem. Installation position and the way is wrong, or contact with muffler is bad, or thermal insulation is bad, can cause fluid for too much.
, thermal expansion pneumatic valve superheat improper adjustment. Fault 2:
the compressor starts, refrigerant flow is larger.
phenomenon: liquid into the compressor; Not the heat; Suction pressure is higher than normal.
may cause analysis:
and installation specification. Because the pipeline flow, indoor machine outdoor position arrangement of wrong, cause downtime refrigerant compressor or evaporator, and in sudden traffic is larger when the phone is switched on.
, compressor in low temperature environment. In the condition of compressor shut down for a long time, refrigerant gradually by temperature is relatively high to low temperature, if the compression at low temperature, may be collected a lot of refrigerant and frozen oil miscibility. In the compressor suddenly boiling when the phone is switched on. This is the request unit after downtime for a long time to boot before, for the cause of the electricity preheating unit.
and external balance pipe plug. Pressure to the sensor cannot quickly passed to the pneumatic valve body, cause closing force is small, pneumatic valve mouth open.
and liquid pipe of solenoid pneumatic valve closing is lax. When stop continuous expansion pneumatic valve provides refrigerants, and concentrated in the low voltage side. Fault 3:
refrigeration system oscillation, or intermittent instability.
phenomenon: inspiratory pressure fluctuation; Suction superheat fluctuation; Expansion of pneumatic valve and sometimes for fluid is insufficient, sometimes too much for liquid.
may cause analysis:
refrigeration system features, design can't restrain system oscillation, 'resonance', similar to the common system does not match.
and selected the oscillation caused by the expansion of pneumatic valve capacity is too large.
, thermal package installation position is not correct. If is accumulated in the muffler, as measured by the temperature of the frozen oil, are prone to oscillation.
and uneven distribution of load on the evaporator. Such as uneven airflow blowing evaporator, the evaporator coil inside each loop refrigerant distribution non-uniform, etc.
, refrigerant contains more water. May cause inflation pneumatic valve ice wall and thawing normal working state.
in the practical work, the thermal expansion of the pneumatic valve operation is often neglected, make thermal expansion pneumatic valve equipment maintenance in a corner. And as you can see failure analysis, need to change the situation of the expansion pneumatic valve to solve the fault is not too much, the key is through analyzing the expansion state of the pneumatic valve, find out other aspects of the problems of the refrigeration system. Pneumatic valve, regularly check and adjust the heat expansion refrigeration equipment to reduce the running cost and prolong its operation life is very important.