Mitsubishi purifier troubleshooting guide

Mitsubishi Purifier Troubleshooting Guide for Marine Engineers

In this article, I am going to share the solution to the most common problems that come with the Mitsubishi Purifiers.

I have worked on four ships with Mitsubishi purifiers, 2 of them were about 15 years old, so you can already imagine the kind of problems I had to face.

With that experience, today, I am going to share the Mitsubishi purifier troubleshooting guide.

How to start troubleshooting the problems with Mitsubishi purifiers?

Let’s suppose; you are on the Watch, Purifier abnormal alarm comes. Steps to be followed for troubleshooting the problem are-

  1. Firstly, acknowledge the alarm from the Engine Control Room and carefully go to the Purifier Room,
  2. There in the control panel, check for the error,
  3. Reset that error from the control panel, and once again start the purifier,
  4. Now take a complete round of the purifier and check for overflow, back pressure, feed rate, and temperature of the oil.
  5. If everything goes well, then fine. If not, continue reading for some common problems that can happen during operation.

Common problems that usually come while purifier is running

These are some of the issues that I came across while the purifier was running fine, and suddenly abnormal purifier alarm came.

Backpressure of the purifier drops suddenly

There are many reasons for a drop in backpressure, but some of the main reasons are

  1. Purifier Feed Pump filter is choked: If the filter is choked, the flow rate decreases, and with flow rate, back pressure also decreases.
  2. Someone disturbed the setting of the Purifier outlet valve: This might sound weird, but there are some people with this kind of attitude. Never mind, make some adjustments and move ahead.
  3. Purifier Bowl starts leaking: If the bowl starts leaking due to any reason, backpressure also drops, thereby giving an alarm. We will discuss the reasons for bowl leakage later in this article.
  4. Bowl is not closing: In this case, backpressure will never develop.

Increase or decrease in Oil Temperature

  1. Oil Temperature Decreases: This generally happens in colder climates when the temperature of the H.F.O settling tank is less, and at the same time H.F.O transfer pump starts, and the temperature of the setting tank drops further.

In this case, Oil Heater is unable to maintain the Set Temperature, thereby giving a low-temperature alarm.

NOTE: If you have 2 H.F.O settling tanks on your ship, then I recommend using both of them one at a time.

When one is in use, raise the temperature of the other one and vice versa.

If you have only one tank, try to fill it up more frequently to avoid filling a large amount of cold oil.

  1. Oil temperature Increases: This happens rarely, but if a High-temperature alarm comes, check the steam controller for proper setting, decrease the steam inlet to the purifier heater.

Purifier Bowl starts Leaking

Some of the main reasons due to which purifier bowl starts leaking while running are

  1. Temperature at the heater outlet is low or high: Take proper actions as discussed earlier.
  2. Feed pump filter is choked,
  3. Bowl is not closing: Check filter before solenoid block, check your hydrophore system, check bowl closing solenoid valve (especially its diaphragm for any defect), check the pilot valve.
  4. Maintenance is overdue: One of the biggest reasons for bowl leakage is maintenance interval; if this is the case, stop the purifier and start preparing for overhaul.

NOTE: You can read the Overhauling procedure of the Mitsubishi purifier by clicking here.

Purifier is not Desludging

Some of the main reasons due to which purifier stops desludging are

  1. Hydrophore pressure is not sufficient: Check hydrophore system, check the filter before solenoid block.
  2. Problem in solenoid valve: Check solenoid valve, especially diaphragm.
  3. Problem in water supply device: Change O-rings and gasket to solve the problem.
  4. Problem in Pilot valve: Change O-rings and other parts if required.

Excessive Vibration in Purifier

At any point of time, if the purifier starts vibrating excessively, Press the EMERGENCY STOP as soon as possible without thinking or trying anything else.

Now, what may be the reason for excessive vibration in the purifier?

  1. Purifier bowl stuck in closed position: Take proper steps as discussed earlier.
  2. Foundation Bolts become lose: Tighten them and start the purifier once again.
  3. Bearings got worn out or damaged: This is the top reason for excessive vibration in the purifier. This may also result in the seizure of the shaft.

NOTE: To avoid seizure of the shaft, don’t let the maintenance of vertical and horizontal shaft to exceed 8000 hours.

Also Read Vertical and Horizontal shaft maintenance of the Mitsubishi purifier.

These were some of the common reasons due to which a running purifier may give an alarm,

Now let’s suppose, you stopped the purifier, did an overhaul, and started the purifier once again.

Also Read: Starting Procedure of Mitsubishi Purifier

Common problems that usually come after Purifier Overhaul

Now we will discuss some of the common problems that come after overhauling a purifier.

Purifier not running on rated R.P.M.

  1. Worn out Friction Pads: When we overhaul the purifier Bowl, we don’t generally remove the motor to check the condition of friction pads.

Changing the friction pads can solve the R.P.M. issue.

NOTE: If you don’t have new friction pads, you can make some scratches on the old friction pads with the help of a hack saw blade and reuse them.

  1. Purifier brakes are not released: Sometimes, we stop the purifier by applying Brakes but forget to reset them before starting.
  2. Problem with Purifier Motor: If there is some problem in purifier motor, overhaul it, change the bearings, and try out once again.

Purifier is not desludging

  1. Water valve is closed: If you forget to open the water, purifier will not open or close the bowl, so open the water and try again.

NOTE: Always make a habit of cleaning the solenoid valve block filter, whenever any maintenance is carried out.

  1. Leaky solenoid valve: Check for the proper functioning of solenoid valve, especially check the diaphragm of the solenoid valve (the hole in the diaphragm sometimes get choked)
  2. Problem in Pilot Valve: If the above problems are not there, the next thing to check for is the pilot valve. Sometimes due to duplicate spares or our own carelessness, we do some damage to the O-rings of the Pilot valve.
  3. Problem in water supply device: If you didn’t overhaul the water supply device, consider overhauling it to eradicate the issue.

Purifier Bowl is Leaking

This is the most common problem we have to face if we take overhauling of the purifier very casually.

Let’s look at some of the common mistakes that can be avoided during the overhauling of a Mitsubishi purifier.

  1. Clear all the holes with compressed air,
  2. Don’t damage the O-rings while fitting them back,
  3. Take the utmost care while taking out and putting back the main seal ring.
  4. Assemble all the parts in the correct sequence referring to the maintenance manual,

Try to avoid these mistakes

Other reasons for a leaking purifier bowl are already discussed in the previous paragraphs.

Steps to carry out Mitsubishi Purifier Troubleshooting

  1. Firstly, press the desludge button on the control panel, now go near the Ammeter of Purifier motor, Amperage should spike at the time of desludge and come back to the normal range once the speed of the purifier stabilizes.
  2. Again press the desludge button and go near purifier overflow port; once desludge takes place, open the port, and observe the following with the help of a torch.
    • At what time bowl starts leaking: After feed valve is open if the bowl starts leaking immediately, this means the bowl is not closed properly. In this case, check the pilot valve, water pressure, water supplying device.
    • If bowl leaks after some time of opening the feed valve: check for the diaphragm of solenoid valve, main seal ring, etc.

With this, we have come to an end of Mitsubishi Purifier troubleshooting guide,

I hope many of you have come across the issues listed here, please share this troubleshooting guide with your friends on social media to support this blog.

I will keep updating this list in the near future to share some more information about Mitsubishi purifier.

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