Upflush Toilet Problems

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An upflush toilet flushes water upwards.
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You need an upflush toilet in any location that is below the sewer — which is most often a basement— because, as its name implies, an upflush toilet can flush waste upward. While you might think that's a recipe for disaster, most models accomplish the task time after time without a hitch owing to the macerator, which turns solids into slurry, or the electric pump that transfers the waste to the sewer via a 3/4- or 1-inch pipe. The discharge system, which is described at Upflush Toilet, is far different from that of a gravity-fed toilet and is the source of most upflush toilet problems.


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Upflush Toilet Operation

An upflush toilet looks like a conventional one, but instead of a tank, you'll see a large plastic box on the floor behind it. This box contains the macerator, the pump and a pressure-sensitive microswitch and membrane that tell the pump when to start and when to stop. On the outside of the box, you'll see a 1/12-inch vent pipe and the 3/4- to 1-inch discharge pipe, which are both connected by special fittings. You'll also see an electric power cord, usually a 1/2-inch water supply pipe and possibly drain connections for the sink and shower.


When you flush the toilet, all the bowl contents enter the tank, and the macerator switches on automatically to grind them. When the slurry level in the tank reaches a preset amount, the pump switches on and transfers all the contents to the sewer via the discharge pipe. A check valve on the discharge pipe ensures that nothing can return to the tank once the pump has ejected it.

Some Common Problems

The macerator is basically a rotating knife, and if you flush something it can't handle, it will get stuck, says HomeAdvisor. This can also happen to the pump, and if either isn't working properly, the toilet may keep flushing, and you won't be able to turn it off. You can remedy this situation by unplugging the toilet, lifting the tank lid and removing the obstruction with tongs. If the obstruction is on the pump, you'll have to remove it from the toilet to inspect and service it.


It's also possible for debris to get lodged in the discharge pipe, and when this happens, the pump operates continuously without emptying the tank. It may take a plumber to find the obstruction and clear it, but if the discharge pipes are exposed to freezing outside temperatures, PlumbWorld advises that the problem may be frozen pipes. If so, the system should operate normally when the temperature goes up.

When an upflush toilet serves as the drain for other bathroom fixtures and water backs out of the fixture drains, it means the pump isn't pumping or the pipes are blocked. Check the power outlet and breakers first, because one of them may have tripped, then listen for strange sounds from the pump, which would indicate it needs servicing. You should also inspect the microswitch and membrane, which measure water level and tell the pump when to come on, for problems.


The Toilet Smells Bad

Scale develops in the tank over time, and because the tank always has a small amount of water in it, the minerals can mix with waste and cause a foul odor. Upflush toilets should be descaled periodically to prevent this issue. You should follow the manufacturer's instructions for descaling, but in most cases, you can do it by filling the tank with vinegar and allowing it to stand for a few hours before flushing it away.



Chris Deziel is a contractor, builder and general fix-it pro who has been active in the construction trades for 40 years. He has degrees in science and humanities and years of teaching experience. An avid craftsman and musician, Deziel began writing on home improvement topics in 2010. He worked as an expert consultant with eHow Now and Pro Referral -- a Home Depot site. A DIYer by nature, Deziel regularly shares tips and tricks for a better home and garden at Hunker and Family Handyman.