Full Answer
Can a common vent heat up a water heater?
In many cases, the exhaust from the larger appliance heats up the common vent, improving the flow of the water heater vent. While properly installed common venting systems are completely effective, there is the potential for backdrafting problems if they are not installed correctly.
What type of venting is used in a water heater?
Atmospheric Venting Standard water heaters—the most common type—often use a method known as atmospheric venting. The vent consists of a vertical or upward-sloping vent duct that typically ties into a common vent. The system works solely through natural convection—based on the principle that hot air rises.
How does atmospheric venting work on a water heater?
Atmospheric Venting. The system works solely through natural convection—based on the principle that hot air rises. Hot exhaust from the water heater naturally rises up through the vent and into the air outdoors, creating a draw that promotes this upward airflow. The power of the draw increases as the vent duct heats up.
How does a standard water heater work?
Standard water heaters—the most common type—often use a method known as atmospheric venting. The vent consists of a vertical or upward-sloping vent duct that typically ties into a common vent. The system works solely through natural convection—based on the principle that hot air rises.
Can two water heaters be vented together?
0:131:40How to Pipe 2 Water Heaters in Tandem Water Heaters NowYouTubeStart of suggested clipEnd of suggested clipSide we need the same rise vertically. And the same distance horizontally until they feed togetherMoreSide we need the same rise vertically. And the same distance horizontally until they feed together to go up a pipe if you do it exactly like this the heaters will be balanced.
What is code for venting a hot water heater?
Clearance to combustibles: for gas fired water heater vents: 6" minimum clearance from single-wall vent pipe or flue-vent connector to any combustible material. Single wall vent pipes cannot pass through a ceiling, floor, firewall, or wall.
Can two gas appliances share a vent?
If venting two or more appliances on the same flue, you have to know the flue can handle it, as determined but the BTU input and other factors. Both or all appliances have to be on the same floor. So, no furnaces in the basement or room heaters on the second level of your home.
How do I plumb my second hot water heater?
0:001:27How to install a second additional water heater in series - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd bridge a second gas line to your new water heater so you just split it add all the same partsMoreAnd bridge a second gas line to your new water heater so you just split it add all the same parts there as well is the exhaust is tapped in from this one. And put on to the second. One.
How do I know if my water heater is Backdrafting?
To check for proper draft, I simply cup my hands around the draft hood without actually touching it. If the water heater is backdrafting, I'll feel warm, moist air coming out of the draft hood.
How far can you horizontally vent a water heater?
National fuel gas codes allow the vent connector to have 1-1/2′ of horizontal run for every inch of vent connector diameter. In other words, a 4-inch vent connector would be allowed to have a 6-foot horizontal run. There are exceptions that allow for longer runs, but this is a good guideline to follow.
What is a stack vent?
Stack Vent. The extension of a soil or waste stack above the highest horizontal drain connected to the stack. Stack Venting. A method of venting a fixture or fixtures through the soil or waste stack.
Can a gas water heater and furnace Share vent?
Vent connectors serving equipment vented by Natural draft (typical water heater) Shall Not Be Connected Into Any Portion of Mechanical-draft systems (80% and higher efficiency gas furnaces). This Means: With Any New Furnace Installation — A Gas Water Heater Must Then Be Separately Vented.
Can you vent a water heater into a chimney?
When venting a gas water heater to a chimney, be aware that holes in the chimney can prevent a good draw on the water heater, causing downdrafts and presenting the risk of carbon monoxide poisoning. To avert this problem, you can vent the water heater to the largest hole in the chimney and cap the remaining holes.
Should water heaters be in series or parallel?
Equipment being equal, two or more heaters connected in parallel will deliver more hot water than the same heaters connected in series. In a parallel configuration, the hot water demand is taken equally from each unit.
Are two water heaters better than one?
Having two heating elements that run independently, dual-element water heaters are typically more energy-efficient than their single-element counterparts. Using less electricity can help lower your monthly energy bills and be better for the environment.
Why does my house have two hot water heaters?
In series, the water comes in to the first water heater, then passes through the second hot water heater, and finally goes to your fixtures. If you turn off the second water heater, then the water in the second one cools down between uses. This results in very long warmup times.
Can you vent a water heater out the side of a house?
The exhaust gases and excess heat produced by your water heater are then vented back outdoors. A direct vent water heater uses special coaxial venting that has separate chambers for intake air and exhaust in a single assembled vent piece. The venting runs from the water heater through the side of your home.
Can I use PVC to vent gas water heater?
A standard will be needed for plastic flue pipes that should include a temperature gauge and a high limit probe. Then PVC, CPVC and polypropylene flue gas piping can be safely used on high efficiency boilers and water heaters.
Can you use flexible duct for water heater?
Every once in a while, we run across flexible vent connectors on water heaters or furnaces. They basically look like a flexible dryer duct, and there's no way this could be a proper installation. But they're actually just fine.
How far does a water heater vent have to be from a window?
If the water heater is installed above the door or window, it needs 12 inches of clearance. A direct vent installation only requires a 12-inch setback from the door or window. If the window does not open, the water heater requires a 12-inch setback.
What piping method is used to add a second water heater?
Once it's determined that adding a second tank makes sense, there are two basic piping methods that work well: reverse-return and series. Each offers independent operation if one water heater fails or needs servicing. Other incorrect piping methods commonly but erroneously used to add a tank not only perform poorly but may also cause stagnation and ensuing water-quality problems.
How much does it cost to add a water heater to a home?
But depending on the extent of the re-routed distribution lines, installation of a separate stand-alone water heater can cost at least $900. Swapping out the too-small heater for a larger unit is another alternative, but the drawback is that the cost of the tank and its installation can easily exceed $1,500. Provided that the existing water heater is relatively new and functions properly, we often recommend adding a second heater and coupling the two to double the supply capacity. This solution averages $700, a substantial savings over the cost of a stand-alone installation.
How many gallons of water should I put in a 40 gallon water heater?
So, if a 40-gallon water heater produces a gallon of thermal expansion, the tank volume should be at least 4 gallons. The majority of potable water thermal expansion tanks are available in a 4.5-gallon volume tank with a factory air-charge of 40 psi. Following installation, that air pressure should be increased to within a few pounds of your incoming municipal or private cold-water pressure.
What is the maximum pressure for a twinned heater?
Twinned heaters can be served by a common expansion tank large enough to handle their combined volumes, or each heater can have its own properly sized expansion tank. These must be rated for potable water and a minimum pressure of 150 psi. Note that standard heating system expansion tanks are rated for a maximum of only 30 psi. Be aware also that thermal expansion tank manufacturers may base their sizing requirements on warmer incoming water temperatures and lower finished water temperatures than may be the case, either of which can lead to undersized thermal expansion tanks, a stressed heater, and a dripping relief valve.
How long does a water heater last?
Water heater life expectancy averages 10 to 15 years. While standard efficiencies hover around 80%, a few gas-fired models offer up to 99% efficiency. The built-in redundancy of a second tank offers the added luxury of never being without hot water, even if one tank fails. And as energy costs rise, the relatively higher price ...
What to do when you run out of hot water?
One of the first things done by the average homeowner who is running out of hot water is to turn up the thermostat on the storage tank. This actually makes some sense because less hot water is required to achieve the same mixed temperature ratio. Raising the storage temperature from 120°F to 140°F will increase energy costs for a standard water ...
Do fossil fuel water heaters have flues?
But remember, a fossil-fuel water heater requires adequate flue-pipe sizing to effectively vent the carbon monoxide produced. If both the new and existing water heaters must share a flue, the flue size must be increased at the junction by at least one pipe diameter.
How Do You Connect Two Tankless Water Heaters?
You have three main choices when you’re using two tankless water heaters. You can install them with independent plumbing, in tandem, or with one dedicated to one appliance.
Are Two Heaters Better Than One?
There are some circumstances where it is better to run two smaller tankless water heaters together rather than choose one much larger unit. For example, with two units, you have some redundancy, so if one breaks down, you can still get some hot water from the other.
What is the venting system for a water heater?
All water heater venting systems use a vent duct or pipe—also called a chimney or flue— to bring exhaust gases from the water heater to the outdoors. The duct may be metal or plastic, depending on the type of vent system. Water heater ducts may lead directly outdoors, or they may tie into a larger vent duct that also serves a gas or propane furnace ...
How does a water heater work?
The system works solely through natural convection—based on the principle that hot air rises. Hot exhaust from the water heater naturally rises up through the vent and into the air outdoors, creating a draw that promotes this upward airflow. The power of the draw increases as the vent duct heats up.
How does a direct vent system work?
With a direct-vent system, air for combustion is drawn from a vent pipe that runs through an exterior wall or the roof. Exhaust gases are vented outdoors through a separate vent duct or through a separate chamber of the same pipe (this requires a double-wall vent duct). Direct-vent systems essentially "breathe" outdoor air, so they are not subject to the effects of backdrafting in the home. They also reduce the risk of accidental fires caused by flammable vapors around the water heater.
What is the process of burning a water heater?
All water heaters that burn natural gas or liquid propane (LP) gas require a venting system. The process of burning of the gas is called combustion and it creates heat, exhaust gases (including highly poisonous carbon monoxide ), and moisture. The water heater's ventilation system removes these byproducts from the home, ...
Why is my water heater venting back?
Proper Venting Prevents Backdrafting. The most common problem associated with water heater venting is a condition called backdrafting, in which exhaust gases from the water heater fail to exit the home via the vent and instead end up in the house. Backdrafting can have many causes, but it is most commonly due to poor vent design or installation ...
Where does the air come from in a propane water heater?
In addition to venting, gas and propane water heaters need an air supply for combustion. This may come from the atmospheric air in the house, or it can come through a vent pipe that pulls air from the outdoors.
What is direct vent?
Direct-vent systems essential ly "breathe" outdoor air, so they are not subject to the effects of backdrafting in the home. They also reduce the risk of accidental fires caused by flammable vapors around the water heater.
How long should a flue pipe be?
The flue piping of the system, whether for single or multiple appliances, should be as short a run as possible, and rise 1/4″ per running foot up and toward the chimney. Whenever possible, do not exceed 10 feet of flue pipe length. Avoid using more than two 90-degree turns in the piping.
What happens when the draft of the stove rises?
When the draft of the appliance rises, the fan wheel of the burner moves air easier. As the draft on the appliance drops, the fan wheel must work harder to move the same amount of air. Proper chimney and flue design, along with proper draft control, allow for an efficient combustion process.
Where should the flue piping be sealed?
The area around the flue piping should be sealed where it enters the chimney.
Do you have to follow the manufacturer's recommendations on venting?
Always follow the appliance manufacturer’s recommendations on venting the particular appliance. It is also just as important to obey your local codes and requirements.
Can you connect more than one oil heating appliance to a chimney?
Connecting more than one oil heating appliance to a common chimney can be easy and beneficial once we understand the basic guidelines. When following the guidelines for installation, the system will work for you. Disregard these guidelines, and the system can work against you. The flue and chimney sizing not only controls the exhaust ...
