PLUMBING

There are three basic types plumbing in residential construction. Water supply, waste, and mechanical (gas or oil to appliances).

Let us start with water supply. Cold water first comes into the building from either the utility meter or well. When the water enters the building it reaches a fork in the road and some is piped into the water heater and the rest is piped directly to the cold side of fixtures, toilets, and hose bibs. Water entering the water heater is of course heated and delivered to the hot side of fixtures.

The water heater tank is filled with water. Beneath the tank is either a burner like that of a stove or inside the tank there are electric heating elements kind of like those seen inside an electric oven. There is a thermostat on the tank that either turns on the burner or the electric element when the water in the tank begins to cool.

Water heater tanks also have a number of safety devices. Keep in mind, a water heater is closed tank with a heat source. Did anybody say “Pipe bomb”? To prevent tank explosion a temperature pressure relief valve is present. This is a valve that releases the water and pressure through a discharge pipe (hopefully terminated in a safe location) when the tank improperly reaches a temperature of 210 degrees or the pressure exceeds 150 pounds per square inch the discharge pipe activates and releases the water.

There is one other type of water heater that is becoming more popular. This is the on-demand water heater. These are sometimes called the flash water heater. These are also called non-storage water heaters. These do not have a tank. Instead they are about the size of a suit case and are installed inside or outside of the building. Cold water enters this device and a computer sensor activates a burner (typically fueled by natural gas). This burner heats the water quickly and it leaves this device as hot water. This is a highly efficient as there is no tank to keep warm, but since there is an unlimited amount of hot water supply, water can easily be wasted by taking extra long showers.

Once the water is used, it’s going to have to leave the building sooner or later. That’s where the waste pipe comes in. Waste pipe is simply a pipe network that is bigger in size than the water supply pipe. It’s a larger pipe because by gravity, it carries both liquid and solid waste out to the sewer or septic system. All very simple but there is one more thing we need to know about waste pipe. Inside the waste pipe there are stinky and combustible gases. So what prevents stinky gases from the toilet from rising up and out of all the bathroom basins and sink drains? Enters the water trap. The water trap is a “U” shaped pipe that is seen underneath sinks and basins. Every drain barring the toilet has a water trap. The water spot in the toilet acts as a trap. The water trap holds a little water at all times to act as a seal to prevent gases from working their way up and out the drain. One more thing waste pipes have. Waste pipes are vented. Waste pipes connected to the waste pipe system that pass through the building and poke out through the roof. There are no covers because if rain water gets in, it’s simply sent into the sewer. Without vents in our waste pipe system water traps would siphon out (or suck dry) and waste would have more difficulty going down the pipe. Imagine you are playing with your straw while enjoying a soda. The vents is like taking your finger off the straw for the soda to drain out. If there is no air behind the waste, it would have difficulty making it to the sewer.

Mechanical plumbing is basically the pipe that brings fuel (typically gas or oil) from the gas meter or other fuel source to appliances such as the furnace, the water heater, the gas stove, the gas oven, and/or the gas dryer. The basics to mechanical plumbing is that gas runs through rigid pipe (usually black steel) and this pipe pokes out from a wall or floor behind or at a gas appliance. From there a gas valve should be established and a flexible gas connector should be established from this valve to the appliance.

In newer construction one may find corrugated stainless steel pipe, which is all flexible. It has yellow coating and should only be installed by one certified to install this system.

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