8 Common Upflush Toilet Problems And How To Fix Them?


Upflush toilets are increasingly becoming common in homes with basements or minimal space to install traditional bathrooms. These innovative toilets allow you to eliminate waste when flushing from below the sewer line. However, there are certain common upflush toilet problems that you need to learn how to deal with.

For example, creating a macerating system that is powerful and quiet, yet compact for installation in tiny spaces often presents a huge problem. Macerating pumps come with their fair share of pros and cons.

Although they require minimal plumbing work and suit basement bathrooms, they often block, fail, or break at some point, and you’ll need to learn a few tricks to solve such problems.

In this blog, we help you identify common potential issues with upflush toilets and how to deal with them. Read on!

Sanigrind Pro Upflush toilet

#1: My Macerating Toilet Keeps Running And Will Not Switch Off

One of the most common problems with macerating pumps is that they occasionally fail to switch off. The pump can flush and keep flushing, even when the macerator is clear.

More often, diagnosing the source of this hitch is not easy. It could be triggered by one problem or a mixture of issues, including:

  • A blockage in the macerator or pump
  • A blockage in the waste pipe leading to the external drain system
  • Damage to the pump’s rubber membrane
  • A faulty microswitch

The Solution

  • A blockage in the macerator – Turn off the power to the pump at the mains supply and physical check if there is a blockage in the pump’s macerator unit. If so, clear it using a pair of thin-nosed pliers as you slowly turn the blade counter-clockwise.
  • A blockage in the pump – Check if cotton buds or other debris are blocking the impellers and remove them. To access the pump, lift the motor out o the unit and turn the unit upside down.
  • A blockage in the waste outlet pipe – Check if the return valve is blocked as this can return the waste as it hits the blockage. To clear this, use thin-nosed pliers to remove the lid of the upflush unit and clear any blockage in the return valve. Sometimes, the return valve can be faulty and will require replacement.
  • The microswitch is misfiring – A misfiring microswitch is another common problem with upflush toilets. Solid waste can get lodged between the switch and the tank floor, which causes the switch to think that the tank is full and needs flushing. In such a case, you will need to clear the tank manually and restart the pump.
  • Damaged rubber membrane – The unit’s rubber membrane can get damaged and cause endless flushing. The rubber membrane is the thin sheet of rubber that water presses upon to switch on the pump. Once it is damaged or loses its seal, waste water can enter the switch and cause it to fail. Fortunately, if your macerating toilet is still within its warranty period, the manufacturer should cover the cost of replacement.

#2: My Upflush Toilet Is Vibrating Violently

If the macerator/pump is making a horrible vibrating noise whenever you flush the toilet, then there could be a foreign object caught in the macerator blade. You can choose to get your hands dirty and fix the issue yourself or call in a service plumber.

The Solution

Turn off the power to the pump at the mains supply (Never remove the macerator lid unless the pump is turned off). Carefully remove the cover and check inside the pump’s macerator if there is any foreign object that tangles the blade. Use a pair of thin-blade pliers to remove the object as you slowly turn the blade counter-clockwise.

#3: My Macerator Keeps Starting Randomly

If the pump keeps firing randomly at different times of the day or night even without someone pressing the push button, then there could be a problem with the microswitch. This issue could be caused by a fault with the rubber membrane that triggers the switch or there could be some waste lodged between the switch and the floor.

The Solution

  • Misfiring microswitch – If the problem is a misfiring microswitch, check if there is any foreign object between the switch and tank floor. This can cause the switch to think that the tank is full and trigger the flushing. Fix the issue by removing any excess waste near the microswitch and restart the pump.
  • The rubber membrane is damaged – If the rubber membrane wears out or loses its seal, waste water can enter the switch and cause it to malfunction. In such a situation, you will need to replace the rubber membrane and the switch. Also check if the push button is stuck in the wrong position.

#4: My Upflush Toilet Continually Trips The Electrics

Macerating pumps use electricity to shred waste and pump it upwards into your septic tank or sewer line. If your upflush toilet system continually trips the electrics, it could be severely damaged and should be handled with great care. First, turn off the mains electricity supply and examine the pump for damage. In many cases, the motor seal is probably faulty. If the unit’s motor seal is damaged, the motor itself could be full of water and will definitely cause a short circuit in the pump’s electronics.

The Solution

Contact a qualified electrician to check the electrical connection.

#5: My Macerating Toilet Is Leaking/Foaming Up

If your macerating toilet’s microswitch grows too old, it may not fire until the tank gets sufficiently full. Eventually, when the microswitch is activated, the spinning mechanism may cause wastewater to escape through the air vents.

The Solution

First, try replacing the rubber membrane that protects the microswitch. Usually, as the rubber ages, it becomes loose, requiring more and more pressure to activate the switch. But if the problem persists after replacing the rubber membrane, it may be necessary to replace the entire microswitch.

#6: My Upflush Toilet Smells Terrible

If your pump has operated for a few years, it is important to give it a thorough cleaning. Follow the manufacturer’s instructions for cleaning the unit correctly.

The Solution

Use a high-quality upflush toilet descaler to clean the pump. Avoid general cleaning chemicals or bleach since they can damage pump components.

Masking the smell

#7: My Macerating Toilet Keeps Blocking And Backs Up To The Shower Basin

If your upflush toilet frequently blocks and backs up to the shower basin, it’s likely that the internal unit or waste pipe is blocked. Waste pipe blockage often occurs when the outlet pipe was installed incorrectly. Typically, the waste pipe should be installed at 45 degrees to ensure that solid waste is thoroughly cleared from the pump and won’t flow back to the tank.

The Solution

First, try removing any blockage from the macerator or water tank. If it fails to work, then the blockage is probably in the waste pipe. You will need to call a certified plumber to inspect and clear the blockage. More importantly, ensure the pipes are installed at an angle of 45 degrees.

#8: My Macerator Is Running But It Is Not Pumping Out

This problem often arises when the waste pipe is frozen, especially in winter.

The Solution

First, switch off the macerator unit and try to remove some of the waste manually, especially if the waste threatens to overflow. Wrap some hot towels along the length of the waste pipe to help loosen up the frozen blockage and finally flush out the waste.

Common Upflush Toilet Problems FAQs:

How Much Does It Cost To Install An Upflush Toilet?

While prices vary widely depending on your specific circumstances, the average cost to install a macerating toilet ranges between $210 and $320 (assuming you won’t be installing completely new plumbing systems- which can get much more expensive). The cost can run as high as $550 if you require a new plumbing network.

Does An Upflush Toilet Need A Vent?

All plumbing fixtures must be properly vented. Your upflush toilet should vent into your house’s main vent stack, which usually extends from the main sewer line all through to the roof. The macerating tank features a vent connection on top to help you with that.

Can You Put A Toilet In The Basement?

With traditional toilet systems, it is impractical to have a toilet in the basement as most models rely on gravity to eliminate waste. However, upflush toilets feature a powerful macerating pump to push up waste even if the toilet is positioned below the main sewer line.

How Do I Clean My Upflush Toilet?

To clean your upflush toilet, pour 1-2.5 liters of non-acid Toilet Cleaner and Macerator Descaler into your toilet bowl. Switch on the macerator pump for a few seconds to enable the descaler to enter the macerator. Switch off the macerator again and allow the descaler to work for 2 hours. Finally, flush the toilet to get a sparkling clean toilet.

How Long Do Upflush Toilets Last?

On average, macerating toilets last about 10-15 years before any mechanical components need to be replaced. American Standard toilets come with a 10-year warranty.

Why Does My Upflush Toilet Smell?

Bad smells can be triggered by a build-up of solid waste or limescale in the 2-3 inches of water that always remains in the macerating unit. To determine if it’s your upflush toilet that’s emitting the bad odor, flush the toilet or fill the basin with water and then unplug it.

In some cases, the smell can emerge from the tank itself, although it is often scent-sealed. Always choose upflush toilets that are EPA-friendly to minimize the chances of bad odor.

Smith Edwards

Smith Edwards is a licensed plumber and writer with over a decade of hands-on construction and home improvement experience and has been providing home improvement advice for over 12 years. Along with his wife Julie, they are bathroom experts from home improvement to shaving and everything in between!

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