Can you vent water heater and furnace together?

Asked By: Rozanne Fanjul | Last Updated: 1st March, 2020
Category: home and garden indoor environmental quality
4.6/5 (2,004 Views . 31 Votes)
Many homes are built with the water heater and furnace sharing the same combustion-gases exhaust vent. This practice is common with standard efficiency (80%) furnaces. When installed correctly, this venting arrangement works with an 80% gas furnace (or lower than 80%) + gas water heater.

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Accordingly, can you vent two water heaters together?

Venting dual gas water heaters. Double the size of a single vent. Both heating water at the same time. Likely hood is they will, regardless of how the two tanks are connected, in series or parallel.

One may also ask, can you vent water heater through wall? All natural gas water heaters must be vented to the outdoors to remove the byproducts of combustion. The vents go directly through an outside wall, and can also bring in combustion air to the gas burner. Most of these units require zero-clearance at the sides and rear, which allows them to be installed in a small area.

Also to know is, can furnace and water heater share PVC vent?

The fan, however, does not exert positive pressure into the flue pipe. Category IV Appliances are mainly high-efficiency water heaters and furnaces that use plastic vent pipes. These appliances also operate with positive vent pressure and cannot share a common vent with a gravity-vented water heater.

How do you vent a water heater into a chimney?

  1. Install an increaser in the largest hole in the chimney.
  2. Install smoke caps in the smaller holes and seal them with furnace cement.
  3. Install an increaser on the flue base on the water heater.
  4. Install the 90-degree elbows on the two increasers, and then rotate the elbows so that they're aligned with one another.

34 Related Question Answers Found

Can you put two flues one chimney?

A single chimney can safely have multiple flues inside the chimney, each flue venting an appliance, fireplace, or other device, provided that the chimney was properly constructed, including the necessary spacing or sealant between the individual flues.

How do you size a flue pipe?

The Right Size Flue Pipe
Measure the hole where the furnace vents. The pipe you purchase should match the inside diameter of the hole. It can be larger but must never be smaller or leaks will result. The average stove and furnace today requires a 3 inch diameter pipe, but can go as large as 8 inches.

Can I vent a hot water heater horizontally?

Water heaters with power venting come with an electric blower fan (often very quiet) installed on top of the water heater and can have either vertical or horizontal vent ducts. Since the vent does not rely on the buoyancy of hot air, it can be run horizontally to the outside of the house.

How long can a furnace vent pipe be?

Vent Pipe Size and Length
Two 45° elbows are equivalent to one 90° elbow. The minimum length certified for use with this furnace is 5 ft and one elbow, not including the vent and air intake terminals.

How do you remove a furnace vent pipe?

Access the furnace through the door on the furnace closet. Loosen the clamp where the lower end of the vent attaches to the furnace using the screwdriver or nut driver. Pull off the end of the pipe from the flange. Tap the pipe with the hammer, if necessary, to dislodge it and pull it off the flange.

How do you vent a furnace through a wall?

Direct Venting uses a power ventilating blower or fan (and in some models a heat exchanger plenum to cool outgoing gases passing through the building wall (sidewall direct exhaust) or roof or through an existing unused chimney through which a vent pipe is passed (vertical direct exhaust).

Can you put a power vent on a regular water heater?

Natural gas or propane hot water heaters are generally less expensive to operate than electric heaters, but installing a standard vent in a house without an existing chimney is expensive. It's easier to run the vent if you install a “power-vented” type of natural gas (or propane) water heater.

Why are direct vent water heaters so expensive?

When using a direct vent water heater, water is heated by the heat of fuel combustion. A direct vent system typically results in lower water heating costs, because the exhaust gases are vented vertically, with no extra power required as is the case with the power vent water heater.

Is it OK to enclose a water heater?

In most instances, a home's water heater is placed in the basement. When the basement is finished so it can be used for another purpose, leaving the water heater in plain view can detract from the appearance of the room. You can enclose the water heater by building a wall around it and constructing a utility closet.

What is a Type B vent pipe?

Type B Gas Vent Pipe. Type B Gas Vent has been engineered to heat up rapidly. It remains hot during the operation of the appliance with minimal condensation in the appliance and vent system. Pipe lengths are available in multiple lengths, 6 to 60 inches, with a full complement of adjustable and rigid fittings.

Can B vent run horizontal?

No, a B vent pipe cannot be terminated horizontally. Under no other circumstances may a B vent pipe terminate horizontally, though. An appliance that is approved to vent horizontally is most often not compatible with the use of a B vent pipe.

How hot is water heater exhaust?

If a water heater is set to store water at 140 F to minimize Legionella bacteria growth, the flue gas temperature will be about 160 F when the heater is new. As scale builds up and the heater efficiency falls off, the flue gas temperatures can easily increase to over 350 degrees F.

What size is water heater vent pipe?

Replace the smaller size vent pipe with a proper / required size: most 30 gallons, 40 gallons, and 50 gallons gas water heaters use 3″ diameter vent pipe.

Can I enclose my water heater?

The short answer to whether a water heater can be enclosed is "Yes," but there are some important things to consider when placing a hot water heater in an enclosed area, whether the unit is gas or electric. Any hot water heater must be installed in such a way as to prevent spills and allow easy access to controls.

What causes a water heater to backdraft?

The main reasons for the backdrafting at the water heater are the poor vent installation and the obstructions found in the vent pipe. This problem affects mainly the atmospheric gas type water heaters that use the natural convection for the removal of the products of combustion, known as the exhaust gases.

Why have a power vent water heater?

A power vent water heater uses a fan or blower to assist in the removal of exhaust gases from the hot water heater. Exhaust gases can be pushed through horizontal exhaust pipes with the use of a fan or blower. The main benefit of a power vent water heater is the ability to locate the water heater away from a chimney.

Does a furnace need a fresh air intake?

Since high efficiency furnaces draw air directly from outside, the furnace itself does not require a fresh air intake in order to replace inside air that otherwise would have been drawn from the room the furnace is located in. The open flue on conventional furnaces better allow for the escape of moisture.