Marine Engineer Officers Guide

Electric Motor Burn Out

Maximize your motor life and improve your operations by taking preventative measures against these common causes of electric motor failure:

1 – Motor Overloads

The first is a motor overload, which causes the motor to draw more current. This, in turn, produces more heat than the motor was designed for, which reduces the life of the motor. Motor overloads usually result from improperly sizing the motor or a change in the driven load, including plugging of the system, a broken gear or frozen bearings.

However, if the motor-overload protective device trips and takes the motor off-line repeatedly, it is not nuisance tripping and the cause should be located, rather than simply installing larger protective devices.

2 – Short Cycling

Short cycling is the process of repeatedly stopping a motor that is already heated to operating temperature, and then starting it again before it has a chance to cool. The result of underestimating the starting frequency of an application may lead to more starts per hour than the motor is rated for. Most electric motor manufacturers specify the maximum number, or frequency, of starts for a given motor type.

3 – Electrical Supply

“Low or high voltage is actually not the cause of electric motor failure as frequently as one would suspect,” says Prince, “unless the voltage change is greater than 10%.” Motors do not give satisfactory service if the voltage consistently varies by more than +/- 10% from the nameplate rating.

Phase voltage unbalance in a three-phase supply can cause electric motor failure due to an excess temperature rise. A 3% voltage unbalance causes an 18% temperature rise in the motor and a current increase of six to ten times the voltage unbalance. Phase voltage imbalance should be less than 1% for proper motor operation. If a motor must be operated with a phase unbalance greater than 1%, the motor should be derated. A motor should not be operated if the phase unbalance is greater than 5%.

Single phasing refers to conditions where one phase of a three-phase electrical system is de-energized. Single phasing creates a problematic situation for a three-phase motor that can continue to operate by drawing more current (thus more heat) on the remaining two phases. Many standard motor starters contain overload relays which will not respond to this situation, however, three-phase “phase protection relays” are available to protect motors.

4- Physical and Environmental Conditions

Motors must be rated and installed to withstand the physical and environmental conditions their operation subjects them to.

Restricted ventilation, or covering the motor’s enclosure with materials, will cause a motor to operate higher than the desired temperature. “A typical compressor room or pump house will heat up quickly if the room is not properly ventilated,” according to Senior Member of Siemens’ Large Motors & Pumps, William R. Finley.

Improper lubrication will not only damage bearings, but can also throw grease into the windings.

Moisture in the form of condensation can cause rust within a totally enclosed motor.

Vibration, belt tension and misalignment are among the major causes of motor failures that started as bearing failures. Where vibration is a problem, electrical connections, if not tight and secure, will be an endless cause of trouble.

“Causes of vibration may be in the motor, such as: unbalance of the rotating element, rubbing parts, loose parts, oil film instabilities, anti-friction bearing problems, electrical design and resonant parts. “Causes of vibration may also be external to the motor, such as: foundation, installation, misalignment, adjacent parts in resonance, and changing conditions after installation and start-up.”

High ambient temperatures (over 104° F for a 40° C rated motor) must be taken into account by derating to a lower horsepower or installing a motor designed with proper insulation for operation at higher ambient temperatures.

Black Smoke from the Funnel: What to do?

Black Smoke from the funnel is a sign of poor maintenance and malfunction of the machinery. It is a serious issue as it violates Marpol 73/78 Annex VI and can lead to inspections and detention of the ship. In a ship with multiple machines the identification of the faulty unit is a difficult task.

The reasons black smoke is wrong are:

1. It indicates that shipkeeping and maintenance is not proper and up to the mark.

2. It indicates the lack of competency of the engineers.

3. It is polluting.

4. It increases the risk of an uptake fire.

Marpol Annex VI has set standards for air pollution and the sulphur content of the exhaust gases. Back smoke indicates that the combustion is incorrect. It suggests a bad fuel efficiency and an increase in the fuel consumption.

Causes of Black Smoke

The dark color of the smoke is caused by suspended fine carbon particles due to incomplete combustion taking place. However the offending machine has to be identified before any corrective action can be made. In marine diesel engines the poor combustion is basically due to two main reasons; the first one is insufficient air supply and the second one is incorrect fuel injection.

The air-related problems in marine diesel engines may be due to the following reasons:

5. The turbocharger air filter is choked.

6. The turbocharger turbine blades are fouled and damaged; therefore it is giving insufficient air to the engine.

7. The turbocharger inlet grid in the exhaust manifold is choked, and therefore the turbocharger is running at low speed.

8. The compressor blades are dirty or damaged.

9. The scavenge ports of the engine may be dirty and choked.

10. The scavenge valves may be faulty or damaged.

11. The nozzle ring of the turbocharger is soiled.

12. The engine room blowers are not supplying sufficient air as the filters are choked.

The fuel-related problems that could cause black smoke are as follows:

13. Low temperature of the fuel causing poor atomization and pe*******on.

14. The fuel injectors may be dripping causing after-burning.

15. The timing of the fuel pumps may be wrong.

16. The holes of the fuel injectors may have become large by wear.

17. Incorrect spring pressure of the fuel injectors.

18. Wrong grade of fuel or low fuel quality.

19. Incorrect valve lift of the fuel injection valves.

20. Unbalanced engine. Thermal and power balancing needs to be done.

21. Overloaded engine due to governor malfunction.

22. Some units may not be firing leading to overloading of the other units.

23. Scavenge fire has taken place

Finding the Source of Black Smoke

The black smoke could come from the main engine, the three auxiliary engines, the oil fired boiler, the exhaust boiler, or the incinerator. A quick trip to the top of the funnel may indicate the source. Once the exhaust pipe has been identified, it should be traced down to the engine room In case it is the incinerator or the boiler, the fault can be discovered soon, but in engines with multiple units it must be established that whether the fault is of an individual unit of is it common to all.

In case the smoke is traced to a multi-unit diesel engine, the procedure of finding the smoking unit is as follows:

24. The engine must be checked for overloading and the exhaust temperatures of the individual units must be checked. The difference in temperature of the individual unit and the average temperature must not exceed 50 degrees C.

25. The engine must be checked for scavenge fire and the under-piston temperature must be checked of all the units.

26. The fuel racks of all the fuel pumps must be checked and must be within limits.

27. The air filter of the turbocharger blower must be checked for choking.

28. The turbocharger speed must be checked and the temperature drop across the turbocharger must be checked.

29. The fuel temperature must be checked and it must be within the range 120 to 140 degrees C for heavy fuel oil.

30. In the case the problem is only due to a particular cylinder, the units must be cut off one by one and for about two three minutes any change in exhaust must be observed.

Colors of Smoke

The color of the smoke tells about the condition of the machines. The ideal color of the smoke should be transparent to slight grey.

31. A white color indicates presence of water v***r in fuel.

32. Blue colored smoke indicates the presence of lubricating oil in the smoke.

33. Dark black color indicates inefficient combustion or the lack or air. It could also be due to scavenge fire or economizer fire or boiler problems.

Corrective Actions

34. The fuel rack of unit is stuck. The rack can be manually pulled back and the lubrication should be done to remove the fuel sludge. In case the rack does not free up, then the engine must be stopped and the fuel pump replaced with another overhauled one.

35. The turbocharger speed has dropped. In this case either the turbocharger is fouled or has become damaged. Also it could indicate choked nozzle ring or inlet grid. The first thing that must be done is that turbine washing or dry grit cleaning must be attempted. If after two or three washings the turbine does not speed up, then it needs to be opened up and cleaned at the next available opportunity.

36. The temperature drop across the turbocharger has fallen. Generally a temperature drop of around a hundred degrees C should exist across the turbine. In case it is less, the turbocharger efficiency has fallen down and must be corrected. Turbine washing is the first attempted solution and should be followed up by opening and cleaning the turbine.

37. The turbocharger compressor is dirty. Again the water washing of the blower must be done and if it is unsuccessful then open and clean.

38. The air filter is dirty. Change the air filter and adjust the copper wire meshing to the correct density.

39. The fuel pump timing is wrong. Readjust the timing.

40. The fuel injection valves are faulty. Stop the engine and pressure test all the fuel valves and correct any faults.

41. The fuel is of low temperature. Heat up the fuel to the correct temperature as per the manufacturer’s advice.

42. The incinerator is over-stuffed. Put in only the correct charge each time.

43. Incinerator temperature is low. Increase the temperature and preheat before burning sludge and garbage.

44. Boiler air register is wrongly adjusted. Adjust as per the instruction manual.

45. Boiler main burner is dripping. Stop the boiler purge and then overhaul the burner.

46. Economizer fire. Slow down the main engine and give boundary cooling. Soot blow if temperature of fire is low (below metal burning point). After stopping clean thoroughly and inspect for damages.

47. Scavenge fire. Slow down the engine and stop. After cooling down, clean the under piston space and investigate fault.

Main Components of 4 Stroke Engine ..

Explanation of Lead acid battery..
Batteries are the most important on ship, encase of blackout batteries are responsible for auto-start the emergency generator and light ups indicator lights at panel boards including navigational and radio communication purposes, especially during emergency cases. Watch the video on site below.
Hit like and share.

http://www.offcenterharbor.com/videos/boat-wiring-part-1-lead-acid-batteries-work-wet-cell-gel-cell-absorbed-glass-mat/?prev=yes&awt_m=1bu00kOA29k&awt_email=fpj_smile20%40yahoo.com

VIDEO: Boat Wiring, Pt 1 - How Lead Acid Batteries Work - Wet Cell, Gel Cell, Absorbed Glass Mat In Part 1 of our boat wiring series, get a professional lesson in how lead acid batteries work - Wet Cell, Gel Cell, Absorbed Glass Mat.

Effects of Electrical shock..
Please wear protective clothing, follow safety Procedures to avoid Accident or injury or even death..
Don't Forget to share to the people you care about and to your companion on-board..Think Safety First.

This is How Lithium Battery Works..

For Electrical calculations..visit the site below..
http://www.smps.us/references.html

Electrical Formulas, Calculations, Basic Electronics Engineering Electronics engineering reference online- electrical formulas, circuit theory and design guides, theorems, electricity and magnetism basics. Calculation of impedances of series and parallel circuits. I-V characteristics for transistors and diodes.

Maintenance on 1st stage and 2nd stage of Main Air Compressor, cleaning/recondition and inspection, Replaced 1st stage v/v w/ ready spare, replaced all gasket..

10 Situations When Ship’s Generator Must be Stopped Immediately

The generator onboard, being the powerhouse of the ship, requires regular maintenance and overhauling to ensure efficient and safe operations. A responsible marine engineer will never wait to carry out maintenance procedures until its machinery is on the edge of breakdown. Instead he will take all necessary precautions to prevent his ship from any impending troubles, which can take place because of engine room machinery failure or breakdown.

There is a thin line between the starting of a problem and the problem taking the shape of major issue. It is only a ship’s engineer who can assess this situation.

Still, cases are observed every year wherein the auxiliary engine breakdown occurs even after giving several indications, foreboding the unfortunate.

Listed below are ten cases wherein you must immediately start the standby engine and stop the auxiliary engine in “trouble” before a dangerous situation takes shape of a major disaster:

1. Abnormal/ Q***r Sound: The ship’s generator engine comprises of heavy oscillating and moving parts. The attached auxiliaries such as turbochargers, pumps etc. are also high speed machines which produce good amount of sound. Any abnormal sound, no matter how faint, must never be ignored. In case of an unusual sound, the engine should be immediately stopped and troubleshooting must be carried out.

Incorrect Approach: The engine room is equipped with hundreds of machinery systems. When the power-plant is in operation, sounds from other machinery can suppress an abnormal sound. Even if you hear something unusual from the generator, you may think it’s coming from nearby environment or machinery. Never ignore even the slightest abnormal sound. Take a second opinion and stop the engine for checks.

2. Smoke: When you see smoke coming from or near the generator, it’s high time to stop the generator immediately. No need to offload the generator as the situation has already passed the danger level. Use the emergency stop button provided in local or remote station. Smoke can be due to friction between moving parts, overheating etc.

Incorrect Approach: PANIC is the first thing that will strike a person when smoke or fire is seen. It might reduce the engineer’s thinking process, which will eventually slow down the approach.

Never panic in such situation. Use the remote start button for the standby generator, which will come on-load almost immediately (normally done through local), and emergency stop the running generator.

3. Unusual Lubricating Oil Parameters: If the lubricating oil temperature has increased beyond normal or the oil pressure has dropped below the adequate level, stop the generator immediately and find out the troubling issue, which might be a dirty l**e oil cooler or chocked filter.

Incorrect Approach: If you noticed a drop in pressure, the first thing comes in mind is to change to standby filter. If your standby filter is not primed and put in service in running condition, due to air lock major bearing damages can occur. It’s always better to stop the machinery and then change it to standby filter, only after priming the same.

4. Higher Differential Pressure: Differential pressure is a term used to asses the condition of l**e oil filter by providing a pressure measurement before and after the filter. The difference between the before and after filter pressures is displayed by a gauge. If the differential pressure is in the higher range, stop the generator and change to standby filter.

Incorrect Approach: On numerous occasions, it has been observed that the generator is allowed to run even when the differential pressure alarm is sounded during maneuvering. Engineers usually prefer not to take risk of changing the filter in running condition, as it may lead to blackout if the filter does not perform correctly. They thus plans to change it once the maneuvering is over. However, due to this sometimes the differential pressure increases further and there is a sudden drop in oil pressure, which trips the generator in between maneuvering. It is very much possible to find bearing metal particles when filters are opened for cleaning. This shows that most of the times engineer are aware of the filter problem but fail to see the bigger picture.

5. Overspeed: Generator is a high speed machinery and over-speeding of generator engine has resulted in explosions and causality in the past. Over-speeding of generator is caused mainly due to problem in the fuel system, specifically malfunction of governor. If the generator is running above its rated speed and still does not trip (Read about overspeed trips here), engineers must stop the generator immediately to avoid major accident. Crankcase inspection and renewal of bottom end bolts is then to be carried out.

Incorrect Approach: During trial running of generator after overhauling, the governor droop is altered to get required speed as stated in the manual. It may happen that the generator over-speeds due to wrong setting or due to stuck fuel rack during this time. Cases of not checking the crankcase and not renewing the bottom end bolts are common causes which lead to bearing damages.



6: Cooling Water Supply: Cooling water supply is an essential entity to ensure smooth running of all high temperature moving parts. If there is no cooling water supply due to failure of pumps, the generator should be stopped immediately to avoid overheating damage.

Incorrect Approach: If their is no cooling water pressure in the line, sometimes engineers try to release air from the purging c**k provided near the expansion tank line of the generator. If the water supply is not available (due to failure of supply pump), it will lead to further increase in the temperature and stoping of the generator at later stage, resulting in seizure of moving parts. Always stop the generator first and then do the troubleshooting. Once the generator is stopped due to starvation of water, fly wheel should be rotated with lubrication to avoid seizing of parts.
A Step-By-Step Guide to Overhauling Generators on Ships is a digital book which explains the Generator D’Carb Procedure in a practical way. From planning to running-in and inspection, the guide provides a detailed explanation of all the aspects involved in major overhauling of generators on ships. Click here to know more about the eBook.

7: Leakage from Pipings: If any leakage is found from the fuel, l**e oil or cooling water pipe, it is to be rectified only after stopping the generator. This will allow the engineer to tackle the leakage easily and better maintenance can be carried out.

Incorrect Approach: If their is a small fuel oil or water leak from any of the pipe connections, tightening of the connection may stop the leak but over tightening may lead to sudden increase in the leakage and with high temperature fuel and water splashing, it can cause severe burn to the operator skin.

8. Vibration and Loose Parts: Vibration is one of the main causes which increase the wear rate of moving parts. If loose bolts are found or heavy vibration is detected when the engine is running, stop the generator engine immediately and find the cause for rectification.

Incorrect Approach: It is not a common practice to check the tightness of the foundation bolts of the generator and its attached auxiliaries such as turbocharger etc. on ships. It has been found that many shipping company’s PMS do not include the foundation bolts and other bolts tightening checks in the routine.

9. Non-functional Alarms and Trips: During any point of time, if an alarm of the running generator is detected not to be working, then the generator needs to be stopped immediately as there is possibility that other important alarms and trips are also not working. This can lead to major failure if any accident occurs in the generator.

Incorrect Approach: Ship crew on several vessels have a tendency to ignore alarms which they think are not important. It is many times observed by Port State Control (PSC) that generator alarms and trips are either not working or wrongly set. Such situations will do no good in saving the generator from disaster. Check all the alarms and trips on weekly basis.

10. Water in Oil: Water leaking in oil will decrease the load carrying capacity of the oil and leads to bearing damages. In such cases, the generator must be stopped if the water content is very high. Immediately find the leakage and renew/purify the sump oil before bringing the generator back in operation.

Incorrect Approach: Several cases have been found wherein the generator l**e oil tests were not carried out regularly and the generator was allowed to run with water content in the oil. The effect of small amount of water is not immediately seen, but it will corrode and damage important parts of crankshaft and bearings in the long run.

The stopping of generator is not limited to above points. There can be several other reasons which would require generators to be stopped immediately. However, it is the duty of the engineer to use his expertise and knowledge to avoid any kind of breakdown well ahead of time.

What would be the Marine engineer say? Probably, push the car and start?

Understanding values of Resistor..

Inside of Vertical Composite Boiler,..Checking condition and physical appearance..

Measuring Main engine Cylinder liner clearance..

10 Boiler Operating Mistakes On Ships

Every engine room machinery system requires a specific procedure for starting and stopping it.
Boiler being one of the most important systems on board ships, requires special care and attention during operation
and maintenance. Inability to do so leads to major failures and accidents, which can not only be life-threatening but
also cause huge damage to the ship’s properly.

Mentioned below are 10 boiler operating mistakes that can lead to heavy loss of life and properly on board ships:

1. Starting a Boiler Without Pre-purging the Furnace: Almost all boilers come with an automation system of starting
and stopping comprising of programmed pre-purging and post-purging of furnace before the burner is fired. Never ignore
or isolate this safety feature. If the boiler has to run manually, it must be pre-purged by means of FD fan for at least
2 minutes. Avoiding this step can lead to blowback and even explosion.

Verticale Boiler

2. Ignoring Furnace Blowback: Several accidents in the past involving furnace blowback have lead to fatal situations on
board ships. Still marine engineers often overlook this danger and fire furnace even when the first attempt ends with
flame failure and blowback. One of the reasons for this is stated above i.e. no pre-purging of furnace.

3. Bypassing Safety and Alarm: This is a common practice among seafarers, who bypass some of the safety or automation
sequences to shorten operating procedure of boilers. Such systems are installed to ensure safety of ship personnel and
thus should never be missed.

4. No checks on Boiler Refractory: Boiler refractory provides better heat-exchanging efficiency and closes/seals gaps to
restrict fire, heat, ashes etc. inside the boiler . Regular inspection of boiler refractory is important as damaged
refractory would expose the boiler shell to flame and heat, leading to bulging or even cracking of the boiler shell.

5. Dirty Gauge Glasses: Gauge glasses installed on the boiler are the only physical means to check the water level of the
boiler. Every engineer knows the procedure to blow the gauge glass for avoiding any kind of blockage. Neglecting this
can lead to wrong water level indication and heavy damage to boiler tubes.

6. Pilot Burner Check: Many engineers remove the pilot burner to check the electrode spark. Such practice can lead to
electrical shock and even fire if the surrounding are not properly cleaned or the pilot burner is kept on oily floor
plate with rags. The best way to check the pilot burner operation is to fit it in place and watch the firing from boiler
inspection manhole located opposite of the burner.

AUX BOILER BURNER ASSEMBLY

7. No Clean-up After Burner Maintenance: When any maintenance work is done on the burner assembly (pilot or main burner)
and the surrounding area is not cleaned before trying out the boiler, there are high chances of fire and explosion as
blowbacks are normal during starting-up after maintenance. Oil spilled inside the furnace and over the burner assembly
can add more to this blowback, converting it into an explosion.

8. Cold Condition – Thermal Shock: Never fire a boiler continuously when starting from cold condition to avoid thermal
shock. Thus in cold condition, boiler should be started by following an intermediate firing pattern, for e.g. 2 minutes
of firing followed by 10 minutes of break. Also, once the boiler starts to warm up the “break” time gradually decreases
and the “firing” period increases simultaneously

9. Wrong Operation of EGB Circulating Pump: Exhaust gas boiler (EGB) normally comes with water circulating pump.
It is important to start this pump well ahead, at least 2 hours, of starting the main engine and to be stopped 12 hours
(the time may reduce depending upon the capacity of the boiler and the geographical condition) after stopping the main
engine to avoid thermal shock and EGB fire.

10. Cleaning of EGB tubes: The exhaust gas boiler (EGB) tubes are arranged in the passage of exhaust gases,
which heats the water in the tubes. If these smoke tubes are not cleaned regularly, it can lead to soot deposits over
the tubes and during low load operation or improper combustion oil can mix up with the soot. When ignited, the soot can
lead to major soot fire followed by hydrogen or iron fire.

8 Most Common Problems Found in Ship’s Refrigeration System..

One of the few machinery systems which needs to run continuously on ships is its refrigeration plant. As a lifeline for all perishable food items and temperature sensitive cargo, refrigeration plant is one of the most important systems on ships which requires utmost attention of engineers at all times.

However, just like all other machinery on ships, the refrigeration system can also get into some trouble from time-to-time. Some of these problems are common but require immediate attention. Mentioned below are eight most frequently seen problems in the ship’s refrigeration plant:

Re**er Plant on Ship

Note: Mentioned in “()” are solutions for each problem.

1. Compressor Starts But Stops immediately- When the compressor in the re**er circuit starts and suddenly stops, it can be because of the following reasons:

– Low pressure cut out gets activated (Ensure that all the suction line valves are in open condition, the refrigeration is properly charged and the low pressure cut out is not defective)

– Defective oil pressure cut out (Check for proper functioning of oil pressure cutout and replace the defective cutout)

– Defrosting timer is getting activated frequently (If the defrost timer is getting activated frequently, leading to cutout of compressor, check and repair defrost timer)

– The l**e oil level is below required level (This can be because of leakage of l**e oil from seal or carry over of oil. Rectify the leakage and refill the oil level)

– Foaming of oil leading to reduced oil pressure (Ensure no foaming takes place, renew the oil if required)

– Motor overload cutouts are activating (Ensure that electrical motor trips are working properly.)


2. Compressor Start and Stops Frequently: If while maintaining the correct temperature of the ship’s provision room or re**er cargo, the re**er compressor is frequently cutting-in and out, then such problem needs to be sorted out immediately. The most normal causes for such operation are:

– Wrong Setting of Cutouts: It may be because the high pressure (HP) cutout is set too high or LP cutout is set too low (Check and change the setting to advisable limit)

– Differential Setting Span is Small: The low pressure (LP) cut out is provided with starting and stopping pressure setting. If the setting span is too small, it will lead to frequent cut-in and cut-out of the compressor (Change the setting and increase the span between starting and stopping compressor pressures.)

– Defective Valves: If the compressor discharge valve is leaky or the line solenoid valve is not closing properly, this will lead to variation in sensor pressure and result in frequent cut-in and cut-out of compressor (Replace all the defective valves)

– Clogged Suction Filters: Compressor is provided with a filter in the suction line. If that is clogged, it will lead to frequent LP cut out (clean the filter)


3. Compressor is Running Continuously : The function of compressor in a refrigeration system is to act as a pump to circulate the refrigerant in the cooling circuit. It can happen that to maintain the cooling temperature in the rooms, the compressor is running continuously. If this happens following can be the causes for the same:

– Refrigerant not sufficient for cooling ev***rator (Ensure thermostatic expansion valve is working properly and clean the filters inside TEV)

– Thermostat low pressure cut-out not activated at low temperature/ pressure (Correctly set the LP cut-out to correct setting)

– Refrigerant charge is low in the circuit (Check for leakage of refrigerant and charge with required refrigerant)


4. Unusual Sound from Compressor: One of the most common problems in any machinery is abnormal sound coming from some of its parts. This may be due to trouble with mechanical components inside the compressor or due to the reasons stated below:

– The capacity control setting is too high, leading to knocking sound during starting (Reduce the capacity control setting)

– The oil pressure is low (Ensure that the oil level is maintained and no foaming of oil is developed. Replenish or refill the l**e oil if required)

– Incorrect alignment of compressor and motor (Check the alignment and set motor and compressor in one line)

– Loose foundation (Ensure that the compressor foundation is secured and all foundation bolts are checked for tightness)

– Loosening of driving belt (Ensure to check the elasticity of the belt and renew if the belt is slack)


5. High Compressor Discharge Temperature: It may happen that all the provision rooms or cargo holds are maintained at correct temperature, but in doing so the discharge temperature of the compressor is going above the limit. This problem may arise due to following reasons:

– Excessive suction temperature due to less refrigerant in the circuit (Recharge the circuit to maintain refrigerant quantity in the circuit. Ensure TEV is set properly and supplying enough to the ev***rator, else degree of superheat will result in increase of suction and discharge temperatures of the compressor)

– Leak in the discharge valve leads to generation of heat (renew the leaky valve)

– Leak in the safety valve (Renew safety valve)

– Open bypass between suction and discharge (control the bypass to avoid this)



6. Ev***rator Coil Icing: Another common problem in re**er system is icing of the ev***ration coils which may happen due to:

– Too low temperature setting ( Increase the coil temperature by adjusting TEV or it’s sensor)

– The coil capacity is less (Install large capacity ev***rator coils)

– Defrost is not operational (Check if the defrost system is functioning at regular intervals)


7. Reduced Cooling Capacity: If the cooling capacity of the plant has reduced and it is not being able to maintain the provision room or cargo hold temperature, following may be the causes:

– Inadequate refrigeration (Charge refrigerant in the circuit)

– Insufficient or damaged insulation in the room (Check and renew the insulation)

– Room or hold is over packed (Ensure that the room is not filled above its capacity)

– Malfunctioning solenoid or TEV (Check the functioning of these valves and renew if not functioning properly)

– Poor thermostat location that senses cold temperatures (Place the sensor of the TEV in proper location i.e discharge of the ev***rator)

– Room door is kept open (Ensure to close the door while exiting the provision room)


8. Reducing oil level in compressor: If the oil level in the compressor crank case of the refrigeration system is reducing within short intervals, this indicates leakage or increase in consumption of l**e oil due to following reasons:

– Nozzle or filter clogged (Ensure that the nozzle in oil return line or filter in solenoid valve is cleaned and not choked)

– Foaming of oil due to liquid in suction line (Foaming of oil may arise due to liquid refrigerant entering the crankcase. Replenish oil and troubleshoot cause of liquid in suction of compressor)

– Drive side seal leaking (The compressor is provided with oil seal at the drive side. Ensure it is not leaking and renew it if required)

– Worn out piston rings/ liner leading to oil carryover in the system (Renew the compressor piston rings or liner)