Macerator Toilet Problems


April 22, 2020

This article is purely to give advice on problems with macerator toilets the Basement Sump and Pump Co are unable to service or repair macerators.

Macerator toilets are commonly used in homes across the UK and remove waste when it is flushed from below the drainage line.

Macerator systems are quiet and powerful but there can sometimes be problems. Macerator toilet pumps can fail, block or even break.

We have provided a list below of the potential problems related to macerators and how these can best be dealt with.

Some of these tasks can be carried out by yourself, however, for peace of mind we would always recommend a trained specialist carries out the solutions to your macerator problems.

Macerator Is Still Running And Will Not Turn Off

One common problem that our customers have is that their macerator toilet keeps running even when turned off. This problem is caused when the pump has already flushed and continues to do so even though the macerator is clear. There are a number of reasons why this might occur:

  • Blocked macerator or pump
  • The rubber membrane has become damaged
  • Blockage in waste outside of the outline pipe
  • The microswitch is misfiring

Blocked macerator or pump

To unblock the macerator, a technician will first turn off the power supply. They will then remove the lid of the macerator. The blockage will most likely be toilet paper or other waste that has become stuck in the blade.

To remove this waste the technician will then use pliers and then turn the blade counterclockwise and carefully remove the waste accordingly.

Macerator Toilet that needs cleaning

Macerator Toilet that needs cleaning

If the macerator pump is blocked then the motor will need to be removed from the toilet. It will then need to be turned upside down so the pump impellers are visible.

Just like with the macerator, pliers will be used, and the engineer will clear the waste. The motor will then be put back into the macerator toilet.

Misfiring microswitch

This is a common problem that occurs in macerator toilets and this occurs when the waste is stuck between the switch and tank floor, which tricks the switch to thinking that the tank is full. The engineer will clear all the waste by hand and restart the pump.

The Rubber membrane is damaged

The rubber membrane will become damaged over time due to the water applying pressure on the seal. This will mean that potentially waste can get into the switch. The only real fix is that you will need a new replacement system that can be fitted by a specialist engineer.

Macerator Toilet Is Vibrating and Making A Loud Noise

If the macerator toilet is vibrating and making a loud noise, then it is more than likely that something has got stuck in the blade mechanism of the macerator.

A service engineer can fix this for you by removing the foreign object from the blade manually removing the object and by turning the pliers counterclockwise.

Macerator Pump is Starting on Its Own

If the macerator pump keeps starting by itself, then it is potentially a problem with the microswitch. For problems to occur with the microswitch it has to have either a fault with a misfiring microswitch or the rubber membrane may have become damaged.

If the microswitch is misfiring it leads the macerator into thinking that the tank is full when it is in fact empty. This will need to be replaced and then the pump can reset.

If there is damage to the rubber membrane, then waste will be able to get into the switch and cause problems to the system. A service technician will need to fit a new switch and rubber membrane.

Macerator Toilet Is Continually Tripping the Electrics

Macerator toilet pumps that continually trip the electrics is something that will need to be handled with care. This usually means that the water is getting into it which means the circuit will cut off so it will not lead to further damages.

With the obvious dangers of water and electric it is recommended that only a trained technician is given the job of repairing the macerator.

If the motor has become damaged or is faulty then a specialist engineer will need to install a new macerator as the motor will be unrepairable.

The Macerator Does Not Smell Nice

If you have had a macerator operating for a long period of time, then it is more than likely it will need a deep clean. The macerator should ordinarily have instructions on how to clean it.

Macerator Toilet Pump is Foaming From The Vent

If your macerator is foaming out of the air vent then it is due to the over use of toilet cleaner or bleach being used. If this continues for a long period of time, then the motor will stop working because it is overheated this is because the toilet pump cannot pump water out correctly.

The solution would be to replace the microswitch to ensure the toilet pump system works correctly.

Macerator Is Running But It Is Not Pumping Water Out

If the macerator is running but is not pumping the waste away, then it is possible that the waste pipes are frozen. In just the same way that central heating systems pipes can become frozen so can those of the macerator.

The service engineer will first turn off the macerator and if the waste has overflowed then they will remove it. Hot towels will be used to heat up the pipes and loosen up the frozen blockage allowing the macerator to pump out the waste.

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  1. Carolyn

    Please could I have a quote for replacement of a macerated pump

  2. Rob

    Hi Carolyn, Thank you for contacting The Basement Sump and Pump Company. If you can send your contact details onto or call 0800 019 9949 and one of our customer services team will be in touch for a possible quote for a replacement of a macerated pump?

  3. Alan davison

    My macerator was working fine then the motor got blocked with someone using wipes and it pop the fuse, i cleaned it replace fuse and it works fine apart from it takes all the water from bottom of toilet, what do you think the problem is please

  4. Joe

    I believe something is blocking the macerator.
    I have the vent coming off the top, it looks like a major problem just to get the lid off?
    Is there a liquid I can pour in to dissolve the blocking?
    Or will time in the water help breakup whatever is blocking it?
    Thank you…

  5. Rob

    Thank you for getting in touch. The HG Drain Unblocker should help dissolve what is blocking up the macerator.

  6. Martin Wheatley

    Hi there, we have a Grunfoss macerator unit that is only about 2 years old. I think there is a blockage, when the toilet is flushed hardly any water leaves the toilet bowl and it takes a long time for this to gradually drain away (the still pump runs to empty the macerator tank). There is also a wash basin in the cubicle – the water seems to drain away from this ok.

    Any help and advice would be most welcome

  7. Rob

    Thank you for getting in touch. We would advise you to contact the manufacturer for support in this matter.

  8. Rory

    Hi please help …..we have had our toilet just a few weeks but the water rises up inside the bowl when flushed and then water spits out of the the shower drain. What can we do to fix this please

  9. Rob

    We would advise the first course of action be to arrange a plumber to get for any issues/ blockages in the pipe.

  10. Alexandria

    Hi my unit keeps making noise for a while, the button on the unit has stopped working and its pumped poop water into my toilet bowl

  11. Rob

    This issue could be caused by a blocked pipe or fault in the system itself, the best thing to do is initially speak to the manufacturer.

  12. Michael

    How much is a service and a micro switch replacement .

  13. Jean Moats

    Hello, my toilet in the basement, pump keeps running about every 40 minutes for about 30 seconds. I unplugged the unit for about a week and plugged it back in to see if that would do anything. At first I did not hear it. I heard it again so I went to unplug it and take the back off to see if it was clogged. The noise had stopped and I smelled a slight burning smell as I walked down the stairs. I flushed the toilet and it did not flush. I am assuming the motor burned up ?

  14. Rob

    Thank you for getting in touch Jean. If you can email us at or call us on 0800 0199 9949 our customer advisor will discuss what the best option is to rectify the issue.

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