"Understanding Your Home" by Building Inspector Mark Visser
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Pressure assist toilets
Compressed air toilets


- Some pressure assist toilets can have a noisy flush. You can't tell which model is noisy by looking at it in the store so ask the retailer for references and actually go through the trouble of checking an installed unit.

- Replacement parts are not always easy to get. Ask the seller or installer about how and where to obtain parts should the need arise in the future. Manufactures of pressure-assisted toilets carry the parts but most retailers don’t. Wholesale plumbing supply outlets carry the parts as well but do not sell to non-plumbers.

- Compressed air toilets are more expensive to purchase than gravity-flow models.

Pressure Assist Toilets

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Pressure assist toilets. Compressed air toilets
The most common type of toilets are those that are gravity fed with water from the tank to create a siphon action to pull waste through a trap way. Manufacturers have been under pressure to create a toilet that uses less water than the conventional toilet. Major improvements have been made with the introduction of dual-flush toilets and low volume toilets.
Water usage for flushing has been greatly reduced with the introduction of pressure-assist toilets. They have been around for several years but mainly for commercial use. Pressure assist toilets are now more widely used in residential homes. Initially there was a problem with the sound level when the toilet was flushed. To a certain degree the newer models are "quieter" and very efficient compared to the earlier compressed air toilets.
Pressure-assist toilets are designed to "push" the contents out of the bowl, as opposed to gravity's siphon action which "pulls".
Compressed air toilets are also known as, but to a lesser degree, power-assisted, pump-assisted, or vacuum-assisted toilets.

When you remove the lid and look inside the tank you do not see water. The only thing that you notice is a sealed plastic tank. This secondary tank holds all of the water needed for a flush. The pressure assist toilet works by compressing air in the plastic tank as water fills the storage tank. Then once the storage tank is charged, it blows the water out under pressure. This strong flow of water cleans the bowl better, removes waste better and flushes further than a gravity fed system. The increase velocity of moving waste to the soil stack will result in fewer blockages. Some manufacturers have added a small water pump to significantly increase the flushing power. This feature however, could be expensive.
To those not hooked up to a municipal water delivery system, adding water to an air filled container is nothing new. Water from the well is delivered to the water storage pressure tank which provides water pressure within the house.

- Greatly reduced water use and lower water bills. A pressure assist toilet uses 1.0 to 1.4 gallons per flush (GPF) or 3.7 to 5 litres per flush (LPF).
- Consistent one-flush performance. The powerful flush leaves no or fewer "skid marks".
- Compared to gravity toilets there are fewer moving part resulting in lower maintenance costs.

You can upgrade a standard gravity fed toilet to a dual flush system but not to a pressure assist toilet.

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