Power Vent Water Heater
Buying Tips
What the power vent water heater is, how it works, review of the top features, how to buy, installation tips and more. Explore the most popular manufacturers of power venting heaters: Rheem, AO Smith and Bradford White.
Power vent water heater is similar to direct vent models, but it uses an electrically operated fan or blower. The blower is used as the assistance to mechanically exhaust the combustion gases to the outside while forcing the fresh air in. Blower assembly is factory installed, so except the installation of the venting pipes there is no other work needed.
Choosing power vent water heaters. Installation tips
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Use the power venting water heaters (PV) when replacing an old electric type or if there is no access to the chimney.
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Use the PV when installing the water heater near the exterior wall.
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When the electrical power is provided (you can plug it into the electric wall outlet).
Note: When choosing the location for your hot water heater, consider the inlet and exhaust vent system piping and combustion air supply requirements. Venting system must comply with local codes and be installed per manufacturer specification. It must be able to run from the water heater to the termination with a minimal length and the number of elbows.
Popular manufacturers of the power vent water heaters
If you are looking for an energy efficient water heater that uses power vent and is coming from the well-known manufacturer in US or Canada, here are the recommendations: Rheem, Bradford White, AO Smith, Kenmore or American. There are also other popular brands such as Whirlpool, State, GSW, John Wood, but we will cover, three the most popular:
AO Smith
There
are over 20 different models from AO Smith
Power vent water heaters are mainly coming from ProMax series, only one is from the Vertex series. The available sizes are in the range from 40 to 75 gallons.
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Vertex Power Vent has the highest energy efficiency of over 90%, mainly thanks to the fully submerged coil heat exchanger. The water heater uses the combined vertical and horizontal vents through the outside wall. The vent pipes are made of the PVC, PP, ABS or CPVC material and have the 4" diameter vents that can run up to the maximum of 128 feet.
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ProMax Power Vent models also offer flexibility and inexpensive CPVC, ABS and PVC pipes. The exclusive 3-position rotatable blower outlet provides greater flexibility during installation. Combined vertical and horizontal vents can run up to 180 feet, using the 4" pipes.
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ProMax Ultra-Low NOx Power Vent has two models, both Energy Star like the models from the above two series, but with the burner that reduces the greenhouse gases significantly.
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ProMax Side Loop (SL) is also available with the power venting and these include side-mounted recirculating taps for use in combined space and potable water heating.
Bradford White
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Ultra High Efficiency model of 60-gal introduces the ultra high efficiency and Low NOx burner. The 4" vent pipe can run up to 170 feet.
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Defender Safety System TTW1 - the vent pipe can be installed either through the wall or through the roof with the 2" or 3" PVC, ABS or CPVC vent pipes that can run up to 120 ft.
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Defender Safety System High EF TTW - these 40, 50 and 60-gal Energy Star models use the 3" vent pipes up to 120 feet.
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High Performance TTW is found as a 55-gal model that utilize vent pipes up to 180 ft.
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Defender Safety System and Non-Defender TTW2 - designed in three sizes 48, 65 and 75-gal these use 3" and 4" pipes with the length of 180 ft.
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TTW Extra Recovery High EF - utilize the powerful blower motor that has the great resistance to the outside winds and can work in difficult venting situations. It uses 3" and 4" vent pipes that run up to 180 feet.
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Rheem
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Professional Classic Plus series consists of the heavy duty power vent models with the 60 and 75-gal tank capacity that use the flexible venting with up to 100 feet vent pipes and new whisper quiet blower. Flexible venting includes PVC, ABS or CPVC vent pipe options with the vertical or horizontal termination.
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40 and 50-gal models from Professional Classic Plus and Professional Classic series are Energy Star rated and have the same venting options as the above heavy duty models.
- Professional Classic series also comes with the Ultra Low NOx type of heaters that are Energy Star compliant.
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Performance series of 40 and 50-gal power vent models are Energy Star approved while high demanding unit of 75-gal is not because of the low energy factor. Venting options are the same as found on the above units.
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Venting Options
The vent pipe of the power vent water heater can terminate horizontally through the exterior wall or vertically through the roof, with the adequate supports along its length.
There are two venting options you should consider for your water heater:
Single pipe system can be installed as the concentric system (two pipes in one) or as the one-pipe system that uses a discharge pipe while internal air, through the heater, gets into the gas chamber for combustion. When the internal air is used, designated room has to be provided with an access to sufficient air supply.
Water heaters with two separate venting pipes use one pipe to supply the air from the outside and the other to discharge products of combustion. They can run either horizontally or vertically.
When the pipes are run vertically, keep in mind to install the elbow fittings at the end of the pipes to prevent the rain or snow to enter. For horizontal termination, provide the slope downward, to prevent potential condensate that can affect the blower operation.
If the water heater is installed in an unconfined space within the building, infiltrated air is usually adequate for proper gas combustion. If it is installed in confined space provisions for the ventilation air must be provided.
Note: If the power vent water heater has to be installed as a replacement for the existing power vented unit in pre-existing venting, the proper inspection has to be performed to ensure that requirements are met.
Venting tips
Buying the venting kit from the manufacturer is worry-free purchase, as they meet standards and safety requirements, but in some cases they can be purchased from plumber suppliers also. Use manufacturer guide and specifications to determine the BTU rating, model, venting lengths and other requirements so you can properly size the system.
For example; plastic pipes cannot be used on tankless water heaters, only stainless steel, due to the acidic nature of the products of combustion.
PVC, ABS or CPVC pipes are recommended for tank-type storage tanks, and the most common sizes are 2", 3" and 4" in diameter, Schedule 40. Very flexible for installation, power vented gas heaters can be installed as far as 180' from the exterior wall and side by side with other furnaces or boilers.
When assembling the air inlet and vent outlet, both pipe diameters must be of the same size. This requirement applies for both 2" and 3" diameter pipes.
Based on the venting length there is a number of elbows allowed. Use manufacturers guide to determine the right length and the number of bends. Venting should be as direct as possible and with a minimum number of bends (pipe fittings), with no reduction in vent diameter, unless otherwise stated.
Some manufacturer manual guides explain that reduction in diameter at any point is allowed as long as the maximum and minimum length requirements are met.
Power vent water heaters, when installed in the building, cannot be connected to the chimney and share venting with other appliances as the significant building depressurization will occur affecting the performance of all gas combustion appliances.
All venting materials and components must be joined with the approved primer-cleaner and solvent cement, but do not cement the vent pipe to the heater. Rubber coupling and gear clamps are supplied with the water heater to connect the vent to the blower. These connections must be properly sealed to prevent leakage of the products of combustion into the living area.
Drawbacks
You should be aware of several drawbacks:
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Sound. The power vent water heater should be installed away from the living room because the fan noise might be annoying.
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Electricity must be provided.
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Sufficient air must be provided.
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PV units are more expensive than the direct or atmospheric vent types.
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Doesn't work during the power outages.
Conclusion: Correct installation of the vent pipe system is mandatory for the safe and efficient operation. With the unobstructed flow of combustion and ventilation air, power vent water heater will work properly for many years.
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