Maintenance Guides 1 min read

Diagnostics and troubleshooting: Insufficient capacity of the industrial cooling system

Technical analysis: Troubleshooting industrial cooling system insufficient capacity: heat load calculation, flow balance

1. Description of the problem and scope of application

This manual is intended for systematic diagnosis and troubleshooting of underpowered industrial cooling systems. The main symptom is the inability of the system to maintain the set temperature of the process, which leads to overheating of the equipment, reduced production efficiency, increased energy consumption and, in critical cases, to emergency shutdowns.

Field of application: The guide covers diagnostics of chillers (compression and absorption), cooling towers, dry coolers and heat exchangers used in various industries of Ukraine.

Severity Classification:

  • Critical: Immediate shutdown of the technological process, risk of significant damage to the main equipment, threat to personnel safety. Requires immediate intervention.
  • Severe: Permanent decrease in production productivity, significant increase in energy consumption, possibility of progressive damage to system components in the short and medium term. Requires urgent diagnosis and repair.
  • Minor: Small but persistent deviations from optimal cooling parameters. It can lead to serious problems if the fault is ignored or progressed.

2. Precautions

CAUTION: Before starting any diagnostic or repair work on the industrial cooling system, all safety standards must be strictly followed, including DSTU EN 378, DSTU ISO 45001.
  • Lockout-Marking (LOTO): Be sure to isolate and block all sources of energy (electrical, hydraulic, pneumatic) in accordance with established company procedures. Check the absence of voltage with a multimeter.
  • Stored Energy: Be careful with refrigerant build-up pressure, hot surfaces, electrical charge on capacitors, and energy from compressed air or springs. Before disassembly, make sure that there is no pressure and no energy.
  • Personal protective equipment (PPE): Always use appropriate PPE: safety glasses/shields, gloves (heat resistant, chemical resistant), protective clothing, protective footwear. When working with refrigerants or chemicals for water treatment, use specialized PPE (for example, respirators, chemically resistant suits).
  • Refrigerants: Refrigerants can cause frostbite on skin contact and are dangerous if inhaled. Provide adequate ventilation. Використовуйте тільки сертифіковане обладнання для роботи з холодоагентами.
  • Hot surfaces: Compressors, condensers and hot gas lines can be very hot. Allow the equipment to cool or use heat-resistant gloves.
  • Rotating parts: Always make sure all rotating parts (fans, pumps) are completely stopped and locked before working.

3. Necessary diagnostic tools

For effective diagnostics, the following set of metrologically verified tools is required:

Tool Specification/Model Measuring range Purpose
Digital multimeter True RMS, at least 600V AC/DC, 10A AC/DC Voltage: up to 1000V; Current: up to 10A; Resistance: up to 40 MΩ Measurement of voltage, current, resistance in electric circuits (motors, sensors, starters).
Current measuring clamps True RMS, at least 400A AC/DC Current: up to 1000A AC/DC Measurement of operating currents of electric motors of compressors, pumps, fans without breaking the circuit.
Infrared pyrometer With laser sight, emission factor 0.95 -50°C to +800°C Non-contact temperature measurement of surfaces (pipelines, compressor housings, electric motors).
Contact thermometer Type K/T thermocouple, calibrated -50°C to +200°C Accurate measurement of the temperature of liquids (water, glycol) at the inlet/outlet of heat exchangers.
Collector of manometers (manometric station) For R-134a, R-404A, R-407C, R-410A; Accuracy class 1.0 Pressure: -1 to 40 bar (low), -1 to 60 bar (high); Temperature: -40°C to +60°C Measurement of the pressure and temperature of the refrigerant in the suction and discharge circuits.
Pressure sensors are portable For water/glycol, accuracy class 0.5 Pressure: 0 to 10 bar Measurement of pressure drop on heat exchangers, filters, pumps.
Portable ultrasonic flow meter For pipelines with a diameter of 25-200 mm Consumption: 0.01 to 10 m/s Non-contact measurement of flow rate of coolant (water, glycol).
Vibration analyzer 3-axis accelerometer, FFT analysis Frequency: 0 Hz to 10 kHz; Speed: 0.1 to 100 mm/s (RMS) Diagnostics of the state of bearings, imbalance, inconsistency of rotating mechanisms (compressors, pumps, fans).
Thermal imager (infrared camera) Sensitivity <0.05°C, resolution 320x240 Temperature range: -20°C to +350°C Detection of hot spots (electrical connections), temperature distribution on heat exchangers, insulation, detection of refrigerant level.
Refrigerant leak detector Electronic, sensitivity up to 3 g/year Detection of refrigerant leaks in the system.
Ultrasonic thickness gauge Range 1.2 to 225 mm, accuracy 0.01 mm Measurement of the wall thickness of heat exchanger tubes to assess corrosion/erosion.

4. Initial assessment checklist

Before starting a detailed diagnosis, perform the following steps to collect primary information:

Checkpoint action Record/Result
Visual inspection of the system Inspect all equipment (chiller, cooling tower, pumps, pipelines) for visible damage, leaks, contamination, unusual sounds or vibrations. Record any anomalies: oil stains, frost, water droplets, traces of corrosion, insulation damage, foreign objects.
Checking work logs Examine the records for the last 1-3 months: history of temperatures, pressures, activation of emergency alarms, performed repairs or changes in the process. Identify trends in parameter changes, repeated accidents, recent interventions.
History of emergency alarms Check the cooling system controller alarm log. Record error codes, time of their occurrence and frequency. For example, "Compressor discharge pressure high", "Water flow low".
Environmental conditions Record the temperature and humidity of the surrounding air, especially for outdoor equipment (cooling units, air condensers). Note: Air temperature ___°C, Relative humidity ___%.
Parameters of the cooling liquid Measure the temperature of the liquid at the inlet and outlet of the heat exchanger/chiller. Check the set value of the controller. Note: Tinput ___°C, Tout ___°C, Setpoint ___°C.
Coolant consumption Check flow meter readings (if applicable) or estimate visually/using a portable flow meter. Note: Consumption ___ m³/h or normal/reduced.
Pressure in the coolant system Measure the pressure at the inlet and outlet of the pumps, as well as the pressure drop at the filters and heat exchangers. Note: Ppump inlet ___ bar, Ppump outlet ___ bar, ΔPfilter ___ bar, ΔPTO ___ bar.
Electrical parameters Measure the operating current and voltage of electric motors of compressors, pumps and fans. Note: Icompressor ___ A, Ucompressor ___ B. Compare with nominal values.
Status of the managing controller Check the controller screen for active alarms, operating mode, set parameters. Record all controller messages.

5. Systematic diagnostic route (Block diagram)

This route will help you consistently identify the root cause of the malfunction. Follow the branching logic:

  1. Start: Insufficient cooling capacity (high process temperature).
  2. Check 1: The chiller is running, but the liquid outlet temperature is above the set point?
    1. NO:
      • Check if the chiller starts at all.
      • If not, check the power supply, starters, overload protection.
      • If it starts but does not cool, go to Check 2.
    2. YES: Go to Check 2.
  3. Check 2: Is the ambient temperature within the tolerance for condenser operation?
    1. NO:
      • If too high for the air condenser/cooling room, the system may be overloaded under operating conditions. This is not an internal fault, but a design limitation or external factor.
      • If it is too low, problems with icing of the evaporator or low discharge pressure are possible.
      • Probable cause: Operation outside the operating range.
      • Solution: Correct working conditions or modify the system.
    2. YES: Go to Check 3.
  4. Check 3: Measure the temperature difference (ΔT) on the cooled heat exchanger (evaporator) and the liquid flow.
    1. ΔT is low, the flow is normal:
      • Probable cause: Low coolant load (insufficient heat transfer), refrigerant problem (insufficient charging, evaporator contamination).
      • Go to Section 6: Trouble-Cause Matrix, Symptoms "Low Evaporator ΔT at Normal Flow".
    2. ΔT high, flow rate low:
      • Probable cause: Coolant flow problem (filter clogged, pump malfunction, closed valve).
      • Go to Section 6, Low Coolant Flow Symptoms.
    3. ΔT is high, the flow rate is normal:
      • Probable cause: Excessive coolant load (exceeding the calculated one), low efficiency of the chiller (contamination of the condenser, non-condensable gases, excess refrigerant, compressor malfunction).
      • Go to Section 6, High Coolant Load or Condenser/Compressor Problems symptoms.
  5. Check 4: Check refrigerant pressures (suction and discharge) and manifold temperatures.
    1. High discharge / condensing pressure:
      • Probable cause: Excess refrigerant, non-condensable gases, condenser contamination (air/water side), fan malfunction cooling towers/condenser.
      • Go to Chapter 6, High Condensing Pressure Symptoms.
    2. Low suction / evaporation pressure:
      • Probable cause: Insufficient refrigerant charge, refrigerant flow restriction (TRV, filter drier), evaporator contamination, low heat load on evaporator.
      • Go to Chapter 6, Low Evaporation Pressure Symptoms.
    3. Low discharge and suction pressure:
      • Probable cause: Compressor malfunction (valve wear, insufficient performance), severe decrease in heat load.
      • Go to Section 6, General Low Refrigerant Pressure Symptoms.
  6. Check 5: Analyze electrical parameters of compressors, pumps, fans.
    1. Increased compressor/pump current:
      • Probable cause: Mechanical overload (bearing wear, contamination), electrical problems (inter-turn short circuit).
      • Go to Section 6, "Increased Operating Current" symptoms.
    2. Reduced compressor/pump current:
      • Probable cause: Insufficient load, phase problems.
  7. If the cause is not found: Consult the manufacturer's documentation or service center.

6. Malfunction-cause matrix

This matrix links common symptoms to their likely causes, diagnostic tests, and expected results.

Symptom Probable causes (by probability) Diagnostic test Expected result (if the cause is confirmed)
High coolant temperature
  1. Increasing heat load
  2. Contamination of heat exchangers (evaporator, condenser)
  3. Insufficient filling of refrigerant
  4. Non-condensable gases in the refrigerant system
  5. Problems with the flow of the coolant (water/glycol)
  6. Compressor failure
  • Checking the technological process
  • Visual inspection, thermal imager, ΔP on heat exchangers
  • Manometer manifold, leak detector
  • Manometer manifold (high subcooling)
  • Flow meter, ΔP on pumps/filters
  • Current clamps, vibration analyzer
  • Qactual > Qcalculated
  • Dirt/scale, ΔP > 0.5 bar (standard); Tcondens. - Trev. > 10°C
  • Low suction pressure, high superheat
  • High discharge pressure, Tdischarge > Tcondens.
  • Consumption < Qnominal, ΔP > 0.2 bar (filter)
  • Reduced operating current or vibration > 4.5 mm/s
High discharge/condensation pressure
  1. Condenser contamination (air/water)
  2. Non-condensable gases in the system
  3. Refrigerant refilling
  4. Insufficient cooling air/water flow (cooling tower/fan)
  5. The ambient temperature is above normal
  • Visual inspection, thermal imager, ΔP on the water condenser
  • Manometer manifold (high subcooling)
  • Manometer manifold, refrigerant scales
  • Fan/pump current measurement, visual inspection
  • Measurement of Texternal.
  • Dirt/scale, Tcondens. - Trev. > 10°C
  • Injection pressure > calculated, subcooling > 8°C
  • Discharge pressure > calculated, increased operating current of the compressor
  • Fan current < nominal, blocked airflow
  • Toutside. > design
Low suction/evaporation pressure
  1. Insufficient refrigerant charge (leakage)
  2. Contamination of the evaporator (water side)
  3. Refrigerant flow restriction (filter-drier, TRV)
  4. Low thermal load on the evaporator
  5. Compressor failure
  • Manometer manifold, leak detector
  • Visual inspection, thermal imager, ΔP on the evaporator
  • Measurement of temperature difference before/after TRV, visual inspection of the filter
  • Checking the technological process
  • Current clamps, vibration analyzer, valve check
  • Low suction pressure, high overheating, leak detection
  • Dirt/scale, ΔP on the evaporator > 0.5 bar
  • A large drop in T on the TRV, the TRV freezes partially
  • Qactual < Qcalculated
  • Low operating current, vibration > 4.5 mm/s, poor compression
Low coolant flow (water/glycol)
  1. Clogging of filters/nets
  2. Pump failure (cavitation, wear)
  3. Partially closed or defective control valves
  4. Air in the circulation system
  5. Increased resistance in the pipeline (corrosion, deposits)
  • ΔP on the filter, visual inspection
  • Flow meter, current clamps, vibration analyzer
  • Visual inspection, valve position check, pneumatics/electrics
  • Sounds (gurgling), visual inspection of the expansion tank
  • Ultrasonic thickness gauge, visual inspection
  • ΔP on the filter > 0.2 bar
  • Pump current < nominal or > nominal, vibration > 4.5 mm/s
  • The valve does not fully open, there is no control signal
  • Uneven flow, noise
  • Reducing the diameter of pipes, irregularities inside

7. Root cause analysis of each malfunction

7.1. Increase in heat load

Explanation: The cooling system is designed for a certain thermal load that occurs during the production process. If the actual heat load increases (for example, due to an increase in production volumes, process modifications, the use of new equipment with a higher heat output, or even due to a failure of the insulation of the heat sources), the system may not be able to cope with the heat removal.

How to confirm: Compare the current technological parameters (production speed, equipment capacity) with the design data. Perform a heat balance calculation for the current state. Use a thermal imager to detect areas with abnormal heat release or damaged thermal insulation.

Damage: Constant operation of the system under conditions of excessive load leads to premature wear of compressors, pumps, increased consumption of electricity, as well as to a reduction in the service life of cooled technological equipment due to overheating.

7.2. Fouling of heat exchangers

Explanation: Heat exchangers (evaporator and condenser) are critical components for heat transfer. Contamination of their surfaces (scale, biofilm, silt from the water side; dust, dirt, grease from the air side; oil or refrigerant decomposition products from the refrigerant side) creates additional thermal resistance. This significantly reduces the efficiency of heat transfer, forcing the system to work under increased pressure or with a greater temperature difference than necessary.

How to confirm:

  • Water side: Measure the pressure drop across the heat exchanger (ΔP). An increase in ΔP above 0.5 bar (compared to the clean state) indicates internal contamination. Visual inspection after draining water or opening inspection hatches. Water analysis for the presence of deposits.
  • Air side: Visual inspection of condenser/evaporator fins. Measure the air temperature before and after the heat exchanger. A decrease in the temperature drop or an increase in the discharge/suction temperature indicates contamination.
  • Refrigerant side: Manometer manifold for subcooling/superheating assessment. Abnormal values ​​may indicate internal contamination or the presence of oil.

Damage: Decrease in system efficiency, increase in energy consumption (compressor works longer and under higher load), increase in operating pressure (risk of emergency operations), corrosion under deposits, possible compressor damage due to increased pressure or overheating.

7.3. Insufficient/overfilling refrigerant or non-condensable gases

Explanation: The amount of refrigerant in the system is critical for its efficient operation. Insufficient filling (often due to leakage) leads to low suction pressure, insufficient cooling of the evaporator and increased overheating. Overcharging results in high discharge pressure, excessive subcooling and can cause hydraulic shock in the compressor. Non-condensable gases (usually air or nitrogen introduced into the system through a leak or during installation/repair) settle in the condenser, reducing the effective heat transfer area and significantly increasing the discharge pressure.

How to confirm:

  • Insufficient refueling: Low suction pressure, high overheating (over 10°C), icing of the evaporator part, refrigerant leak detector.
  • Overcharging: High injection pressure, low superheat (less than 3°C) or no superheat, high refrigerant level in liquid receiver.
  • Non-condensable gases: High injection pressure, while the injection temperature is significantly higher than the condensation temperature corresponding to this pressure (according to the refrigerant tables). Subcooling of the refrigerant at the outlet of the condenser > 8°C.

Damage: Inefficient operation of the system, increase in energy consumption, damage to the compressor (due to overheating during underfilling or hydraulic shocks during refueling), refrigerant leakage is an environmental problem and a violation of DSTU EN 378.

7.4. Violation of the balance of heat carrier flows (water/glycol)

Explanation: An adequate and stable flow of heat carrier (water or glycol solution) is necessary for effective heat removal. Reduced flow can be caused by clogged filters, malfunctioning circulation pump (wear, cavitation, electrical problems), partially closed or malfunctioning control valves, air pockets in the system, or increased resistance in the piping due to corrosion/deposits.

How to confirm:

  • Filter clogging: Measure the pressure drop across the filter. If ΔP > 0.2 bar for clean filters (the value may vary, compare with the design), the filter needs cleaning.
  • Pump failure: Measure the fluid flow with a portable flow meter and compare it to the nominal. Check pump operating current (current < rated at low flow may indicate cavitation or impeller wear; current > rated at low flow may indicate mechanical problems). Listen to the pump for unusual noises, measure vibration.
  • Valve problems: Visually check the position of the valves. Check the control signal on the control valves.
  • Air in the system: Listen for characteristic gurgling sounds in the pipelines, check the liquid level in the expansion tank.

Damage: Insufficient heat transfer, local overheating in process equipment, cavitation in pumps (which leads to their rapid wear), increased energy consumption of pumps, uncontrolled process temperature fluctuations.

8. Step-by-step troubleshooting procedures

8.1. Restoration of normal heat load

  1. Step 1: Review the process flow. Determine if there have been changes in production (increased power, new formulation) that may have increased heat generation.
  2. Step 2: Assess the thermal insulation efficiency of process equipment and pipelines using a thermal imager. If damaged insulation is found, repair or replace it in accordance with DSTU EN 13162.
  3. Step 3: If the load increase is constant, review the design capacity of the cooling system. An upgrade or addition of additional cooling modules may be required.
  4. Verification: After eliminating the cause, check the coolant temperature and the process temperature. They should stabilize at a given level.

8.2. Cleaning of heat exchangers

8.2.1. Water side cleaning (evaporator, water condenser)

  1. Step 1: CAUTION: Apply LOTO procedures. Isolate the heat exchanger from the system, drain the coolant.
  2. Step 2: Open the heat exchanger covers. Visually assess the degree of pollution (scale, biofilm, silt).
  3. Step 3: Mechanical cleaning (for tubular heat exchangers): use specialized brushes of the appropriate diameter and cleaning machines to remove deposits. Follow the heat exchanger manufacturer's recommendations.
  4. Step 4: Chemical cleaning: For stubborn deposits, use specialized chemical cleaning solutions. CAUTION: Follow the safety rules when working with chemicals (PPE, ventilation) and disposal of used solutions in accordance with DSTU ISO 14001. Flush the system to neutral pH.
  5. Step 5: After cleaning, assemble the heat exchanger, fill it with coolant, remove the air.
  6. Verification: Start the system. Check the ΔP on the heat exchanger (must return to design values ​​< 0.2 bar). Check the compressor discharge temperature (for the condenser) or the evaporation temperature (for the evaporator). They should decrease to normal working values.

8.2.2. Cleaning of the air side (air condenser, dry cooler)

  1. Step 1: CAUTION: Apply LOTO procedures. Turn off fans.
  2. Step 2: Remove large debris (leaves, paper) by hand or with compressed air (from a distance so as not to damage the ribs).
  3. Step 3: Use an industrial pressure washer with a wide spray nozzle (not a point jet) and special condenser cleaners. Wash in the direction opposite to the air intake.
  4. Step 4: Rinse thoroughly with clean water.
  5. Verification: Start the fans. Check the compressor discharge temperature - it should decrease. Visually make sure that the ribs are clean.

8.3. Correction of refrigerant charging and removal of non-condensable gases

  1. Step 1: CAUTION: Apply LOTO procedures before working with depressurization. Work with refrigerants should be carried out in PPE and with certified equipment. Connect the manometer manifold.
  2. Step 2 (for underfilling): Use a leak detector to locate and eliminate any leaks. After repair, evacuate the system to deep vacuum (0.5 Torr or 67 Pa). Charge the system with refrigerant to the weight specified by the equipment manufacturer using a refrigerant scale.
  3. Step 3 (for refilling): Slowly drain excess refrigerant into a certified recovery cylinder. CAUTION: Never release the refrigerant to the atmosphere. Monitor the manifold pressure and temperature of the gauges until the nominal values ​​are reached.
  4. Step 4 (for non-condensable gases): If non-condensable gases are detected, they must be removed (degassing). This can be done by pumping from the upper point of the condenser into a special cylinder with further disposal or by using special installations for the regeneration of the refrigerant. After that, perform a complete vacuum and refill.
  5. Verification: Start the system. Check suction and discharge pressure, superheat and subcooling. They must correspond to the calculated values ​​for the given refrigerant and operating conditions (for example, superheat 5-8°C, supercooling 3-6°C).

8.4. Restoring the balance of coolant flows

  1. Step 1: CAUTION: Apply LOTO procedures before working on pumps or valves. Check and clean all filters and screens in the coolant circuit. If ΔP on the filter > 0.2 bar, replace or wash the filter element.
  2. Step 2: Check the operation of the circulation pump. Measure current, voltage, vibration. If the current deviates from the nominal, or the vibration exceeds 4.5 mm/s (RMS), the pump may need to be repaired or replaced. Check for cavitation (noise, uneven pressure).
  3. Step 3: Check the position of all control and stop valves. Make sure they are fully open or installed correctly according to the flow diagram. Check the control signals on the automatic valves.
  4. Step 4: Remove air from the coolant system through the air valves (vents) at the upper points. Check the fluid level in the expansion tank and, if necessary, top up the system.
  5. Step 5: If internal piping is suspected, consider chemically flushing the circuit.
  6. Verification: Start the pumps. Measure the coolant flow rate (must match the design) and pressure drops on heat exchangers and filters (must be within normal limits). The temperature of the coolant should stabilize.

9. Preventive measures

The root cause Prevention strategy Monitoring method Recommended interval
Increase in heat load Regular review of technological processes, assessment of heat balance during changes. Optimization of thermal insulation. Analysis of production data, calculation of heat balance, thermographic control of insulation. Quarterly / when changing the process.
Contamination of heat exchangers Water treatment (filtration, corrosion/scale inhibitors, biocides). Regular mechanical/chemical cleaning. Air filters for air condensers. Water analysis (pH, hardness, salinity), ΔP monitoring on heat exchangers, visual inspection. Water analysis: weekly. Inspection/Cleaning: monthly (air), quarterly/semi-annually (water).
Insufficient/overfilling of refrigerant, non-condensable gases Regular checks for refrigerant leaks. Proper vacuuming of the system during installation/repair. Accurate filling by weight. Use of leak detector, refrigerant pressure/temperature monitoring, overheating/subcooling, visual inspection for oil stains. Monthly / quarterly (leak check).
Violation of the balance of coolant flows Regular cleaning/replacement of filters. Planned maintenance of pumps (checking bearings, seals). Calibration of control valves. Removing air from the system. Monitoring of ΔP on filters, liquid flow, operating current and vibration of pumps. Checking the operation of the valves. Filter cleaning: monthly. Maintenance of pumps: every six months/yearly.
Malfunctions of compressors/fans/pumps Scheduled maintenance according to the manufacturer's recommendations (replacement of lubricant, filters, bearings, belts). Vibration control. Monitoring of operating current, vibration, body temperature, lubrication pressure. Lubricant analysis. According to the PPR (planned and preventive maintenance) schedule, vibration control: monthly.

10. Spare parts and components

The timely availability of quality spare parts is critical to quickly restoring the cooling system. UNITEC-D GmbH offers a wide range of components that meet DSTU EN, ISO standards.

Description of the part Specification When to replace Category UNITEC
Filter elements for water/glycol Mesh (50-200 microns), cartridge (1-25 microns) When ΔP > 0.2 bar is reached or according to the maintenance schedule (monthly/quarterly). Filtration of liquids
Circulating pumps According to the design flow and head (for example, from 5 to 100 m³/h, head 10-50 m) In case of significant wear (vibration > 7.1 mm/s), loss of productivity, damage to seals. Pumping equipment
End seals for pumps Material: silicon carbide/graphite/EPDM When leaks are detected, according to the PPR schedule of the pump. Sealing elements
Refrigerant R-134a, R-404A, R-407C, R-410A (depending on the system) If necessary, refueling after eliminating the leak, complete replacement in case of contamination. Refrigerants and lubricants
Temperature/pressure sensors PT100, NTC, 4-20mA, 0-10V In case of failure, inaccuracy of readings (calibration check). Sensors and automation
Control valves 2-way, 3-way, with electric drive/pneumatic drive In case of jamming, malfunction of the drive, loss of tightness. Shut-off and regulating fittings
Condenser fans Diameter, power, number of revolutions (for example, 800 mm, 1.5 kW, 900 rpm) With significant wear of bearings (vibration > 7.1 mm/s), blade damage, electric motor malfunction. Ventilation equipment

To order and select the necessary components, visit our UNITEC-D Electronic Catalog.

11. Links

  • DSTU EN 378: Refrigeration systems and heat pumps. Requirements for safety and environmental protection.
  • DSTU ISO 14001: Environmental management systems. Requirements and instructions for use.
  • DSTU ISO 45001: Occupational health and safety management systems. Requirements and instructions for use.
  • Instructions for operation and maintenance from equipment manufacturers.
  • UNITEC-D training and professional development materials.

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