Troubleshooting Common Problems: Thetford Toilet Won’t Flush

The necessities of life. You can’t get along without them. One of these necessities is a working toilet. When it doesn’t flush things can get quite uncomfortable. Learning how to fix your non-flushing toilet becomes another necessity in life especially when you are in an RV or trailer.

When you are troubleshooting any mechanical item, always go for the simplest fix first. If it is the problem you save time, money, and energy. Then if it isn’t the problem you have ruled one possibility out. The simplest fix in a Thetford toilet would be the fuse.

To learn more about troubleshooting a Thetford toilet just continue reading our article. it has the information you want to know about so you can fix your non-flushing toilet without calling in a professional. It only takes a few minutes to get this information.

Thetford Toilet Troubleshooting


Replacing the fuse is always a good idea for your first troubleshooting option. Many times this 3-amp fuse will blow on you for any number of reasons. That is why you should do what other owners do and carry spare fuses.

Then if your fuse continues to blow after repeated replacements, you have another electrical issue that you need to deal with. A short in the system or a malfunctioning control panel will most likely be the source of the problem.

Replacing the control panel is often your only solution and if you buy through Thetford expect to pay an elevated cost. Another place to look will be in the toilet itself. If you see debris coming into the bowl with the water, then you need to add a little filter to the waterline.

An inline water filter should solve this problem for you and it doesn’t take long to install. Unlike finding the fuse box to replace a fuse.

Cassette Porta Potti Won't Flush

It may be a small toilet but there may be a wide range of sources keeping it from flushing. Like other Thetford electric toilet models, the first place to look will be the fuse. It could have blown and all that needs to be done is replace it.

Another source of the problem may be the microswitch. If it has gone bad and malfunctioned then you will most likely have to replace it. Another place to look will be the pump.

For some reason, the pump may not be as cold-protected as you would think. Even a good frost can damage it. The only recourse you have here is replacing it. To find the pump you need to remove the toilet paper holder and follow the wires.

Then do not forget about those tiny little animals that like to explore RVs and trailers. Sometimes a mouse or a rat can get inside and chew a wire. It has happened to at least one owner so double check to make sure all your wires are connected and not broken somewhere.

Thetford Toilet Manual Flush Problems


Usually, there is very little that can go wrong with a manual flush toilet. There are not as many parts that can break or become disconnected and mice certainly cannot chew through any exposed wires.

If you have a flushing problem, you can check the freshwater hose. This hose can come loose and lose its connection to the bellows. next, check your water valves to see if they are open or closed.

This is a simple thing but sometimes people forget to open them after some other important duty they need to perform. While you are checking the valves look for blockages in the line or at the bellows.

Then check the bellows themselves. They may have been torn or split in some fashion and you lose all flushing power. Finally, at the bottom of the toilet, there are 3 plastic fittings. If any of them are broken, that will stop the toilet from flushing.

That problem is a warranty fix if your toilet is still under a Thetford warranty.

Thetford Toilet No Power

Like other issues, there are a few sources for this problem. The first place to look will be the fuse. You can’t escape it. When the toilet doesn’t flush and you see there is no power, the fuse could have blown without you knowing about it.

Then you should check the microswitch. It is possible to push this switch too hard and push the switch out of position. All you have to do is open up the plastic cover and see if the switch is dangling loose.

Press the switch to see if it still works and if so, re-position it and you should be good to go. Next on the list would be the fuse holder. If the contacts are bad then you won’t have a good connection robbing you of any power you need. Just clean up the holder to make a good connection.

Finally, check the control panel to make sure it is working and has not malfunctioned on you. Replacing this part is about your only option if it is bad.

Where Is The Fuse on a Thetford Cassette Toilet?


In some trailers, the fuse is going to be in a very inconvenient spot for you. It is well hidden and you have to pull the toilet out of its place. After you do that, you will find a removable cover on the back wall.

After removing that cover, you should be able to find the fuse. It is said that if the fuse inside the fuse box is one size, for example, 3-amps, then you should replace it with a 3-amp fuse.

You are not supposed to go higher as that fuse is protecting something further down the electronic line and a larger sized fuse, for example, a 5 or 6-amp one, will let too much power go through and ruin that protected part. or assembly.

The exception to this rule would be if a previous owner put the wrong size fuse into the fuse box.

Thetford Toilet Won't Stop Running

You can check the water valve and buy a replacement kit. But that may not be the problem. It may but it is a little bit of work and you may still end up with the toilet not shutting off.

The most likely problem will be the defuser. many campgrounds do have a high iron content and that content will damage your toilet system. Part of the damage will be a clogged defuser.

The lime and sediment do build-up and will create a shut-off problem for you. A simple soaking in pure vinegar should help get rid of the lime and sediment. You will need to remove the defuser and place it in a large enough pot, bowl, or another container.

After soaking, use a small wire to clear out any small holes so that there is a clear path for the water to flow. Before re-installing the defuser test it out to make sure it works again.

Thetford Toilet Won't Open


The slider can be an issue if it is not locked into place. Also, you may find that the slider blade doesn't work when sliding it back into place, you did not get it back far enough.

Another suggestion is that somehow you put the slider in backwards and it won’t work until you remove it and re-install the correct way. Then there is the weight problem.

Not the slider’s or the toilet’s but yours. Sometimes people‘s weight pushes the plastic toilet out of shape. When this happens, the slider gets jammed and will not work.

To fix this you have to remove the cassette and look up into the loo hole. Then take the appropriate head screwdriver and loosen the screw on the white cog. Remove the cog, test the slide then replace the cog in the right position.

How Do You Flush a Thetford Cassette Toilet?


For some models, this is a very simple process. All you have to do is look on the wall near the toilet, if it is a cassette-style toilet, and find the little button to push. it should be right next to the level indicator.

All you have to do is push that button but not too hard and the toilet should flush. The level indicator lets you know when the holding tank is full and needs emptying.

Some Final Words

Thetford seems to have made a very simple toilet operation so that you can troubleshoot most problems yourself. That makes repairs simple especially when you are out in the wilderness far from any professional and expert help.

The above information should get you on the right path to being able to fix those simple problems with ease. A few moments of your time and the right parts are all you need.

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