211 Gallon Combination Low-Pressure/Buffer With 3 Heat Exchangers

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  • 211 gallon StorMaxx™ CTEC Tank
  • 3 heat exchangers
  • perfect for combined system
  • removable insulation
  • 39in x 79.5in (D x H)
SKU: StorMaxx-CTEC-213-3HX-V4 Category:


The StorMaxx™ CTEC 211G is a large solar hot water storage tank with 3 built-in coil heat exchangers, a durable steel body and PVC coating. The StorMaxx™ CTEC is great for domestic solar hot water system installations.

SunMaxx StorMaxx™ CTEC Solar Tank water heaters, offer a cost-effective water heating alternative. The insulation can be easily removed thanks to a large zipper in order for the tank to fit in 32 inch entry ways. These tank include three exchanger coils, two bare steel coil for the solar loop and/or boiler tie-in and a 54 square foot stainless steel domestic hot water exchanger at the top of the tank.

StorMaxx™CTEC Tank Features

  • Tank delivered already assembled – easy installation process
  • 3 Heat Exchanger inside the tank
  • Suitable for combined system
  • 211 gallons storage tank
  • 39 IN x 79.5 IN (DxH)
  • Removable insulation

What parts & accessories do I need?

Universal fittings (for FlowMaxx series piping). Easy to stock in your tech-van, less parts to inventory.
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Technical Details


  • Volume: 211 gal
  • Diameter: 39 IN (with insulation)
  • Height: 79.5 IN
  • # of HX: 3
  • Insulation: Removable 

Technical Features:

  • Number of Circulation Ports: 6 
  • Heating Area (Top/Bottom): 25.83 ft2
  • Heat Exchanger Corrugated Tube: 54 ft2
  • Heat Exchanger Water Content (Top/Bottom): 3.83 G 
  • Heat Exchanger Water Content Corrugated Tube: 7 G
  • Heat Exchanger Operating Pressure (DHW): 232 PSI
  • Heat Exchanger Max Temperature (DHW): 230F
  • Heat Exchanger Operating Pressure (Bottom): 44 PSI
  • Heat Exchanger Max Temperature (Bottom): 203F
  • Buffer Tank Operating Pressure: 87 PSI
  • Buffer Tank Max Temperature: 203F
Installing the ports in the bottom parts is not recommended by SunMaxx Solar ™ . They are always installed in the top of the NP tank due to some reason. Firstly the water is filling the tank to determined level. Ports are located above the water surface - no leaking water from tank.  Locating the ports in the bottom parts can cause the leaks and have to be well isolated. Moreover, parts for inslling can cost a huge amount of money. That all issues may lead to some problems,  that SunMaxx Solar ™ install ports on the top locations.
Cleaning the tanks is a process which is simple but easily can cause some troubles. Cleaning the outer layer you can you a pressure washer - it should work. When you want to clean inner site you can also use that device. Before you start remove all the heat exchanger coils carefully, don't cut the rubber membrane. Also the pressure washer can cause some damages in the surface of it, so remember to wash it carefully. After processes place all compactness on their place.
The drain back tank are perfect solution for solar thermal system in the area where climate is challenging.  That means extremely hot or cold temperatures. These tank allows all the water in the system (collector and piping) to drain into the tank reservoir. The water also protects the system form freezing and overheating. Below there is a the simplest scheme of the system with basic components.
The are a lot of different methods how can you check the water level and measure it. The simplest method is to use the wooden stick (length is greater than tank height) or line ended with some heavy weight. After that you can measure the level with measuring tape. For sure you can find some sophisticated methods but using simple one you will reduce amount of money spend on a special equipment.How can you do it in a 5 simple steps:
  1. Remove the top lid of the NP tank.
  2. Take a stick or line and put it to the tank (in both situations this items should touch the bottom lid).
  3. Mark a level of water and take out stick or line.
  4. Measure the distance with a measuring tape - you will instantly know the level of water in your tank.
  5. Put the top lid on the NP tank to close it.
The amount of heat exchangers which can be fit in the tank mainly depends on the size of the NP tank and its increasing with the diameter of the tank. Before you buy the heat exchanger please check two parameters:
  • The height of the NP tank - heat exchangers can't be higher that tank
  • Maximum amount of HX which can be fit in the tank
All the information which you need are located in the table for every tank or in datasheet (LINK). 

Connecting the heat exchanges depends on a customer requirements. The number of HX depends on some factors like tanks size, number of collectors and heat requirements. There are some possibilities to connect the heat exchangers. In our offer 80/80 Stacked 3/4" Corrugated Stainless Steel HX and 90 3/4" Corrugated Stainless Steel HX. Customer can connect HX in few ways. Only Solar Side, no connection in DHW side or both side connected.

DHW&Solar Side Connection - Stacked HX


Connection used in stacked HX. One of the most common type of HX connection. Requires some additional elements like HX Connection Tees. Applicable for connection HX on DHW side and Solar Side. For more accurate questions you can contact the engineering team.

Solar Side Connection - Stacked HX


Connection used in stacked HX. Requires some additional elements like HX Connection Tees. The connection type uses only the Solar Side ports. There is no heat exchanger connected with DHW Side.

DHW&SolarSide Connection - HX


Connection used in single HX. Requires some additional elements like HX Connection Coupling. Applicable for connection HX on DHW side and Solar Side.  One heat exchanger is connected to solar loop, there other is connected to DHW loop. There is a possibility to add more heat exchangers on both side. In this case you will need some extra elements like HX Connection Tees.

SolarSide Connection - HX


Connection used in single HX. Requires some additional elements like HX Connection Tees. The connection type uses only the Solar Side ports. There is no heat exchanger connected with DHW Side.

Sunmaxx Solar tanks are typically used to pre-heat to an existing primary tank. This solutions has some advantages and its definitely more effective than installation the integrated heat source inside the solar tank. Pre-heating help to reduce the heat loses and price of electricity bills. The main factor of this solution is efficiency .
Yes you can. But we are recommending to use dedicated parts to our installations. All products can be easily connected using the SunMaxx Solar products. Moreover they we designed to different type of connections. Changing the parts and system installation may led to some problems or improper way of working the system.  If it is not enough for you , call us we will help you.
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  • 7 years limited on tank and coil heat exchanger
  • 3 years limited on tank and coil heat exchanger in all commercial installations

Additional information

Weight39 lbs
Dimensions39 × 83 in