800 Gallon Non-pressurized Buffer Tank


800 Gallon Commercial Solar Hot Water Storage Tank

SKU: StorMaxx-NP-0800G-6FT Category:
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How to order? 

  • Place your order online or contact our office to order directly with the sales team.
  • Orders placed online will be confirmed within 24 hours by our order team.
  • SunMaxx Solar™ is a manufacturer of solar hot water equipment.
  • Availability and production lead-times vary based on our production queue.

Manufacturer Direct Pricing

Please note the referenced prices online are for manufacturer direct pricing only. For wholesale & distribution inquires, please contact our office for an offer.

Want to speak with our office? Call us 1-877-786-6299


The Non-pressurized Commercial Solar Hot Water Storage Tanks are perfect for Large Domestic Hot Water Preheating applications and can be used for small radiant/space heating applications for residential commercial and municipal locations.

Due to their special construction and design these Commercial Solar Hot Water Storage Tanks are able to be shipped within a crate that is only 18 inches wide allowing them to be easily delivered to and maneuvered around almost any work site – simple on site tank assembly is required.
Commercial Solar Hot Water Storage Tanks are available with a number of internal copper coil heat exchangers designed to meet the needs of nearly any solar water heating application need to be bought separately!

Need Assistance?
If you have questions need help or simply feel uncomfortable placing your order online feel free to contact the product representative at 1-800-786-0329.

StorMaxx™ NP Tank Features

  • Suitable up to 20 collectors ~ 580 ft2 required
  • Max 5 heat exchanger inside the tank
  • Standard sensor ports for all tanks – see in tech. specification
  • Solar & Ice Storage Buffer Tank

  • Perfect for Large DHW Preheating and for small radiant/space heating
  • Foldable design, easy to transport and move through standard 32″ doors
  • Possibility to designate port locations for the manufacture of your tank
  • Water fill port at the top of the tank (1″) included

  • Tanks made in USA
  • Heat exchangers made in USA

What parts & accessories do I need?

Heat exchangers are not included with a tank. They must be purchased separately. For the assistance please call our sales representative.

StorMaxx™ NP Port Location Guide

Possibility of designing port locations for the manufacture of your tank.
Please use the information below to complete the diagram. StorMaxx™ NP Port Location Worksheet can be downloaded in Downloads & Datasheet section down below the page.

The image on right represents three diagrams of an NP tank. You will be writing on the EXTERNAL TANK SURFACE diagram to designate port locations for the manufacture of your tank. Please use the information below to complete the diagram.

Sensor Ports
Sensor ports are standard on all tanks. All 4’ tall tanks get 2 sensor ports, one 2” below the water level, and one 2” above the water base. All tanks taller than 4’ get a third sensor port centered between the other two. Sensor ports are placed near requested piping ports unless otherwise specified.

Piping Ports
You must choose the ports you want installed in the tank and specify their locations. Above water level pass-throughs should be placed on the blue line. Available ports are listed in the chart below. On the EXTERNAL TANK SURFACE diagram, draw a circle where you want each port, and write the letter code from the chart below in the circle designating the port type. If you want your below water level ports at specific heights, write the measurements on the diagram.

Above Water Level Ports
Available PVC Pass-Throughs

CodeDiameter (in)Suitable for:
A13/4" copper
B1-1/41" copper, 3/4" SS flex
C1-1/21-1/4" copper, 1" SS flex
D21-1/2" copper
port location

StorMaxx™ NP Tank Usecases/Applications

  • Hotel and restaurants
  • Commercial projects
  • Dairy farms
  • Office buildings
  • Students dormitories
  • Hospitals
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Technical Details

Technical details

  • Max Temperature: 180 °F
  • Dimensions: 63in x 72in (D x H)
  • Weight: 281 lbs
  • Construction: Round, 0.032 embossed aluminum
  • Wall Material: EPDM Liner
  • Cover sheet: Aluminum
  • Insulation Material: Rigid R14 isocyanurate foam
  • Tank Sizes: 150 – 5000 gal

For the technical details please see the StorMaxx data sheet in Downloads & Datasheet section.

Technical Features:

  • Suitable for installation in Category E; For engineering calculations, please contact our engineering team for consulting services.
  • Seismic Cleats allow for installation of tanks in seismic zones
  • For HX Sizing: Please contact SunMaxx engineering for proper sizing.
  • Folded construction: tanks fit easily through standard doorways and other openings
  • Both tanks and heat exchangers are made in USA

The technical drawings presented below show placement of pipe pass-through ports, sensors, number of water coil heat exchangers, solar loop heat exchangers and the mounting of the tank to the surface. Please contact our Engineering Department for more information regarding custom designs.

np mount1
np mount2
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. Drain back
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). NP tab  

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.


  • 7 years limited on tank and coil heat exchanger
  • 3 years limited on tank and coil heat exchanger in all commercial installations