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Used in Closed Loop Heating Systems

Commercial Hydronic Buffer Tanks

10-119 Gallon
Long Lasting
Superior Performance

Vaughn's Hydronic Buffer tanks are designed to be used in closed loop heating systems with low-mass boilers, geothermal systems, wood boiler installations, and chilled water applications. A buffer tank helps to improve system efficiency in hydronic systems operating below the design load conditions by preventing the low-mass boiler from short cycling. System short cycling can cause the heat pump or boiler to operate less efficiently and may also lead to premature equipment failure. Vaughn buffer tanks are manufactured using a heavy gauge steel inner tank surrounded by a minimum of 2" foam insulation, resulting in very low standby heat loss. The vessel is protected by a high-impact composite jacket material that cannot rust or corrode. The hydronic buffer tanks are available in sizes ranging from 10-119 gallons, and are manufactured with four 1.5" tappings for primary/secondary connections. An immersion temperature control well is located in the middle of the tank to ensure accurate temperature sensing for heating and geothermal applications, along with a conveniently located boiler drain for periodic sediment removal. Also included is a fitting for an air eliminator at the top of the vessel, reducing air accumulation (and the potential for corrosion) in the system.

To size your Hydronic Buffer Tank, use the following formula:

Hydronic Buffer Tank Size = [Required System Volume] – [Actual System Volume]

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  • Heavy gauge carbon steel storage vessel
  • Four 1.5" NPT primary/secondary connections
  • Optional Air eliminator prevents air accumulation in the system
  • Immersion thermostat control well for accurate temperature control
  • 3/4" boiler drain provides easy access for sediment removal
  • Warranty 3 year, non-pro-rated
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Additional Product Details

Dimensional Data

10 20 16 21.5 14.75 11.125 9 7.5
20 20 16 32.75 25.25 17.125 9 7.5
30 20 16 40.625 32.75 20.875 9 7.5
40 20 16 56.25 48.5 28.75 9 7.5
50 22.75 19 49.75 41.375 25.375 9.375 7.875
80 26 22 57.25 48.375 28.875 9.375 7.875
100 26 22 67.5 58.875 33.875 9.375 7.875
120 28 24 67.5 58.875 34.125 9.375 7.875
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Recovery Capacity (Gal./Hour) For Various Wattages & Water Temperature Rises

Wattage 130° 120° 110° 100° 80° 60° 40° 20°
1500 4.6 5.0 5.5 6.1 7.6 10.1 15.4 30.7
2000 6.3 6.8 7.4 8.2 10.2 13.6 20.5 41.0
2500 7.8 8.5 9.2 10.2 12.8 17.1 25.6 51.2
3000 9.4 10.2 11.1 12.3 15.4 20.5 30.7 61.5
3500 11.0 11.9 13.0 14.3 17.9 23.9 35.9 71.7
4000 12.6 13.6 14.9 16.4 20.5 27.3 41.0 82.0
4500 14.1 15.3 16.7 18.4 23.1 30.7 46.1 92.2
5000 15.7 17.0 18.6 20.5 25.6 34.2 51.2 102.5
5500 17.3 18.8 20.5 22.5 28.2 37.6 56.3 112.7
6000 18.9 20.5 22.3 24.6 30.7 40.8 61.5 123.0
7200 22.6 24.5 26.8 29.5 36.9 49.1 73.8 147.6
9000 28.3 30.7 37.2 41.0 51.2 68.3 102.5 205.0
10000 31.5 34.1 37.2 41.0 51.2 68.3 102.5 205.0
12000 37.8 41.0 44.7 49.2 61.5 82.0 123.0 246.0
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  • Custom primary/secondary connection size: specify 1.5", 2" or 3" (1.5" connections standard)
  • Electric backup elements
  • One or two side-mount, all copper heat exchanger. Specify 3/4" (single or double wall) or 1" (single wall only)
  • Air Eliminator
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Buffer Tanks Specific Questions

It depends.  The Uniform Plumbing Code (UPC), section 510.5 states In seismic zones 3 and 4 water heaters shall be anchored or strapped to resist horizontal displacement due to earthquake motion. Strapping shall be at points within the upper one-third (1/3) and lower one-third (1/3) of its vertical dimensions. At the lower point a minimum of four (4) inches (102mm) shall be maintained above the controls with the strapping."  If the installed location is in these seismic zones then a strap/restraint system is required.  Otherwise please consult with a plumbing engineer to determine the proper installation method for your water heater.
Yes, Vaughn advises that a drip pan with a proper drainage connection be installed under your water heater.   In some locations drip pans are required by code and in other situations they are highly recommended, but not required.  In either case, if a water heater leak or a dripping relief valve could result in property damage then a drip pan must be installed under the water heater, even when not required by code.
Vaughn uses a blown-in polyurethane foam insulation for all cement lined water heaters and tanks up to 120 gallon capacity. This insulation has an R value of 7.2 per inch. Most Vaughn tanks have a minimum of 2 inches of insulation resulting in an R value of 14. Certain models are available either standard or as an option with 3 inch insulation and therefore have an R value of 21.
The water heater must be stored in the orientation of intended use (vertical, horizontal). The recommended ambient air temperature range is between 50 and 105 degree F and not exceeding 65% Rh. Under no conditions should the unit be subject to freezing temperatures. The unit is intended to be stored indoors, protected from the elements. Desiccant material should be inserted into the electric control panel and heating element terminal house (if applicable). Prolonged storage will require periodic inspection of desiccant. For cement lined tanks only, place approximately 10 gallons of water in the tank before closing and sealing all openings to ensure a humid atmosphere for the lining is maintained. Cap and seal all openings and tank tappings and/or flanges. Provide the necessary protection to ensure the tank and all accessories are protected from physical contact that could result in damage. Shrink wrapping or other suitable protective plastic may be applied to the exterior. Start up and installation guidelines must be followed, with particular attention to testing of the electric heating element.
Legionella is the bacteria responsible for Legionnaire’s Disease, an acute bacterial infection of the lower respiratory tract. This bacterium was first identified in 1977 by the Centers for Disease Control. Pontiac Fever is a less severe, non-pneumonia, flu-like disease that is associated with and likely caused by Legionella bacteria.   Legionella is a fairly common water bacterium and has been found to exist widely in many surface water sources including lakes, rivers, streams and ponds.  It can also be found in ground water sources and some soils.   At the levels found in these naturally occurring sources it typically does not pose a threat to public health.  When the bacterium enters a domestic water system it can find an ideal host environment of warm water temperatures (105-115°F), stagnant water areas (isolated storage tanks and dead-end piping legs) and ample food sources (sediment, scale, deposits and biofilm). Under these conditions Legionella can rapidly colonize, forming higher concentrations that can pose the public health threat of Legionnaire’s Disease.    There are many methods of controlling colonization of Legionella bacteria; a widely accepted and preferred method is to maintain the hot water system storage temperature continually at or above 140°F.  Unfortunately, the elevated temperature necessary to minimize the growth of and kill Legionella bacteria has the potential to cause serious thermal shock and scalding injuries.  As such, many plumbing engineers will specify that the water heater be set to maintain water temperatures at 140°F or higher to reduce the risk of Legionella, but then specify the appropriate mixing valve to ensure safe delivery of hot water to the fixtures.  For a more thorough discussion of Legionella please go to here and the following link to the US Department of Labor OSHA information regarding Legionnaires’ Disease OSHA here
Yes. The heat exchanger is fully removable in all Vaughn indirect water heaters. The benefit to having a removable heat exchanger is that the coil can be removed for cleaning and de-scaling for improved performance and efficiency when used in hard water applications. It should be noted that the heat exchanger is not removable and the coil cannot be cleaned in many other indirect water heater brands.
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