【 Weak current College 】 maintenance practice for ground source heat pump unit

1. maintenance content

1. check unit operation, see operation records and set alarms
1.1 check unit operation records, analysis of the last warning content
1.2 check alarm possible occurrence points
1.3 records unit current problems

2. check unit external circumstances
2.1 check unit appearance, corrosion and contamination
The unit external 2.2 checking interface, the leakage of solder joints
2.3 check compressor, motor and other parts base fixed
2.4 check and fastening units of all moving parts, the system fixed pipeline components. Including foot bolts and screws, etc.
2.5 check unit pressure hose connector and reliable check compressor base fixed situations
2.6 expansion valve fixed reliability and temperature sensor, balance pipe fixed reliable
2.7 check evaporator, condenser connect fixed and reliable

3. check unit condenser and evaporator of pollution
3.1 check frozen water evaporator case scaling
3.2. detecting water temperature difference between the side and the refrigerant
3.3 evaporator water system contamination for evaporator sewage or recommended chemical cleaning

4. check the system status with lubrication system
Compressor lubricant oil 4.1 check, if necessary, the lubricating oil
4.2 clean or replace oil filter
4.3 clean compressor oil pan
4.4 check and clean the compressor suction strainer
4.5 checking system drying, drying filter replacement

5. check compressor and motor side insulation resistance value and current value
5.1 measurement value compressor motor insulation
5.2 measurement pump motor insulation value
5.3 after running compressor, pump check voltage, three-phase current value

6. check the electrical wiring in the control box, the operational reliability and should be avoided because of exposure to vibration, running wear damage
6.1 check compressor terminal box Terminal fixed reliable within
6.2 check pumps reliable wiring
6.3 check control box incircuit various contacts fixed reliable

7. check all electrical wiring contactors, solenoid valve, electrical components
7.1 check and clean the compressor contactor, pump contactor contacts reliability, no obvious Burns
7.2 check the solenoid valve coil unit in good condition and action correct, if necessary, for maintenance and replacement

8. check the calibration of the sensor unit and instrument, pressure switch setting value
8.1 calibration chilled water, cooling water, and water temperature sensor, the outdoor temperature sensor, flow switch
8.2 verification of high and low voltage sensor, water temperature sensor values
8.3 checksum table, low table high
8.4 check screw compressor spray liquid temperature sensor
8.5 check reliability of high-voltage switch

9. convert system check valves
9.1 check conversion valve performance
9.2 check conversion valve action correctness

10. check the water side set spilled water separator
Detailed inspection and source 10.1 side coil heat exchanger branch pipe leak situation, the valve opens the window well.
Calibration to the source side 10.2 balance valve open position

11. Verify air conditioner side pressure differential bypass valve action status

12. check and adjust the status of the generators running (with reference to the cold water unit debugging code for execution)

2. the main parts maintenance
1. compressor maintenance
1. Visual inspection of the compressor
Checking method: Visual
Check criteria: check compressor valve connection reliability and export, whether there is a leak; testing should be aware of the compressor running voice to determine whether there are abnormal
2. voltage and current measurement
Measure tool: clip-on ammeter with clip-on ammeter working voltage and current. When running the current measuring cables should be in the Centre of the measuring loop.
Measurement standards: 380V running voltage range (± 10%), and run-current should not be greater than the motor nameplate of rated input current.
3. measurement of insulation resistance
Measure tool: megohmmeter
Measurement method: power off the unit, with three megohmmeter detection compressor relatively resistance meets the standards. If the machine head of time is not enabled, you should first be set in the crankcase electric heating cycle
Still, oil heating unit, the unit oil cavity of freon evaporation, improve the accuracy of measuring resistance measurements Note: no measurement under the vacuum State, prevent the insulating layer of insulation breakdown caused by the accident
Measurement standards: compressor motor insulation standards for not less than 500 MB, the actual measurement value should be greater than 100
Megohm is qualified, under the hot and cold insulation value is greater than 8 megohm is allowed to run.
4. determination of the oil products:
Extract from the unit in a little frozen oil loading container, take a drop into acid reagent bottle observation of acidity, with a contrast ratio of color card. Consistent with a controlled than color card colors should not be replaced refrigeration oil can be extracted from the unit in a little frozen oil into the container, to minimize the exposure time in the air, and then use the PH test strip discriminant oil acidity. Comply with the requirements of oleic acid degree does not need to be replaced refrigeration oil blotting paper check oil impurities, such as a carbon emission or other impurities and should be replaced refrigeration oil.

2. maintenance of condenser
Maintenance tool: pipeline cleaning machine or chemical cleaning agent
Maintenance: water cooled condenser with shell and tube water-cooled condenser, condenser cleaning and maintenance work is important to maintain cooling water, cooling water chemical treatment should be conducted on a regular basis to ensure heat transfer tubes not scaling, maintenance can be guaranteed by mechanical cleaningRaising and chemical cleaning maintenance (refer to chemical cleaning procedures).
Mechanical cleaning methods:
1. shut down the cooling water and export the valve
2. detach the condenser and rear end cover
3. clean the condenser end cover, water Chamber cavity scaling and corrosion
4. pipe cleaner cleaning heat pipe
5. after washing with water, until you reach the standard, and then put the end cover
Maintenance standards: maintenance after water room, the overall heat transfer tubes visually clean, no apparent scaling wall
Notes:
1. what methods of cleaning, according to the condenser tube forms to identify and prevent damage to the inner rib pipe.
2. uniform chemical cleaning must
3. the concentration of detergent and cleaning time to follow the manufacturer instructions for
4. rinse time must be clean, completely, without residue.

3. maintenance of the evaporator
1. check the frozen water and evaporator scaling, do a good sewage water exchanger
2. detection of water side and refrigerant temperature difference between
3. When should open maintenance evaporator bottom of sewage sludge discharge valve and the impurities, if necessary, remove the sewage valve, to increase the outfall
4. it should be noted that during the winter does not use water to prevent freezing damage caused evaporator
5. prevent sensor shall fall out lead to induction of temperature is the temperature of the air instead of evaporator temperature, resulting in frequent low temperature alarm
6. maintenance work can reference when sewage, the following steps:
1) running water pump 10 minutes
2) water quality in the outfall inspections
3) according to the color of water, suspended solids, rust, etc., we recommend that users use mechanical cleaning or chemical cleaning
4) cleaning, sewage valve open to most, sewage
5) drainage net again pouring water, running for 30 minutes and then view a water, if necessary, then the job once

4. Unit piping and fittings maintenance
4.1. expansion valve of checking
Testing tools: surface contact thermometer
Checking method: check the expansion valve Junction has no traces according to overheat, compressor unit back to the gas side condensation level determines the unit run time expansion valve opening is appropriate, check that the sensor is loose, bundled with position sensor of the capillary is no wear and tear. On balance pipe connection nut, bolt do antirust protection valve.
4.2 as liquid mirror checks and drying filter replacement
Check tool: surface contact thermometer
Checking method: Visual inspection as liquid mirror display cases in the test strip judge system refrigerant of humidity, confirm the need to replace dry filter, surface contact thermometers for measuring the temperature difference is lower than before and after the filter, that filter clean 0.5 ℃.
Drying filter replacement method:
1. first close the high-pressure fluid, moving units exported angle valve and pumping systems for low-voltage side of the refrigerant (non-vacuum suction), and then locking unit
2. detection of drying filter pressure is lower than the adjacent 2.0kg/c © o, if you add refrigerant pipes to the parts of the emissions of gaseous refrigerant
3. diagonal release of drying filter end cap screws (release note difference before to prevent temperature difference of water into the system), emptying refrigerant then quickly change the old filter, clean and dry the filter cylinder internal, get a new filter, add a small cylinder of port sealed refrigeration oil.
4. vacuum supplement a little refrigerant, open front closed valve maintenance standards: sight glass indicates in a dry area is less than the difference before and after the dryer 0.5 ° c
4.3 electrical components maintenance
Testing tools: Multimeters and selection of ampere meterbr>Maintenance method:
1. check and fastening electric line terminal, check the contactor contacts of Cauterization.
2. the contact points with canvas and grinding to remove oxide, if Burns serious, it is recommended that you replace.
3. check if the solenoid valve, such as 4-way reversing valve, solenoid valve, the unit loading and unloading of solenoid valve, solenoid valve for spraying liquid, electric heating and other actions properly, or to replace or repair and maintenance standards: contact clean, no Burns oxides, Sync contact, non-ripple noise.
4.4 check all safety devices
Maintenance methods: inspection and testing of all security devices (thermal protector, flow switch, pressure switches, and other protection devices), check the tuning parameters
Maintenance standards: thermal protection with good retention, wiring intact, flow switch, open and close motion normal, high and low voltage switch action in 24.5 ± 0.5Bar.

3. test run
Reference water cooled chiller debugging code for execution
Steps in brief:
1. preheating unit
2. computer blank test
3. turn on debug running, view the full load and part load of work status
4. According to the operation of the State, to decide whether to add refrigerant
5. check the superheat and, if necessary, make appropriate adjustments
6. check compressor cylinder head temperature and exhaust temperature
7. press the actual working for plant operation parameters set
8. record run parameters, fills in the maintenance report duplicate customer sign-off (a paying customer, an EMC archiving)