SmartMaxx™ Solar Hot Water Controller for Domestic Hot Water & Space Heating with 3 Relays


Premium commercial & residential solar hot water controller Made by SunMaxx Solar in Germany.

  • Suitable for 95% of all solar hot water systems
  • Easy to program and setup (included wizard) 5 min setup
  • Made in Germany
  • Three relays (control up to three different pump / control circuits)
  • Easy mounting bracket on back of each controller
  • Relay rating 2A (up to 4A if fuse changed)


SKU: SmartMaxx-Pro-L4 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


SmartMaxx™-Pro Controller Series

SunMaxx Solar offers pre-packaged solar hot water heating systems for both the do-it-yourself customer and the professional installer. Each system includes the primary components required when installing a solar hot water heating system. It is our goal to keep our product cost low in order to ensure that we are making renewable energy products more affordable to the community.
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Easy to mount & install

Each SmartMaxx controller includes integrated ease mounting housing (for mounting to a wall or other surface).
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Universal with Muli Relays

Universal for all solar hot water systems. Suitable for commercial or residential use. Includes three switch relays. Please see the full manual for all pre-programmed designs.

Features & Benefits

  • Self-explanatory full text menus for quick understanding
  • Wiring terminals for up to 6 sensors (PT1000)
  • Conforms to CAN/CSA E60730-2-9-1 (R2007)
  • Ideal for small commercial and large residential solar hot water and heating systems
  • Full Graphical display
  • Standard SmartMaxx Pro L4 max. amperage is 2A.
  • The product version can be updated to 4A if needed

Technical Details


  • Mains Voltage: 100 – 240 VAC
  • Mains Frequency: 50 – 60 Hz
  • Power Consumption: 0.5 – 2.5 W
  • Controller Max. Amperage: 2 or 4 A
  • Overall Dimensions: 6.42 x 4.33 x 2.04 in
  • Aperture Installation Dimensions: 6.18 x 4.17 x 1.22 in
  • Display: Full Graphical / 128 x 64 dot
  • Network Connections: CAN Bus
  • Real Time Clock: RTC / 24hr Power Reserve
  • Temperature for operation: 32 – 104 °F
  • Temperature for transport / storage: 32 – 140 °F
  • Air Humidity for operation (@77°F): 85%


Before you start making it on your own, please read the 3 easy steps, which can help to understand it.

Step 1 – Insert screwdriver into the upper hole. Push the lock clamp inside down. Keep the screwdriver in this position.

Step 2 – Insert wire/cable into the lower opening

Step 3 – Remove screwdriver. The clamp will lock the cable.

learning this prevent form damaging and incorrect wire/cable connection to the controller.

In the controller there are five possible slots (S1 to S5), where the temperature sensor can be connected.  Every slot can be used for a single temperature sensor and usually S1 is used for bank of solar collector.  Moreover there is a possibility to connect VFS sensors, which are usually mounted on Domestic Water Skid and Solar Pump Skid. These sensors measure water temperature and flow rate. Operational value of voltage is 12 V AC/DC applicable and suitable for all this connection in the solar controller..

There is a possibility to buy an additional accessories like DataLogger which is collecting the most important data during controller working time.  It is useful accessory which can help to optimize the whole system. Remember that you have to buy a USB Power for DataLogger, that it is not included in the package for more details please contact the engineering team.

SunMaxx’s Pump Stations are an all in one solar hot water component featuring a circulator pump, a digital controller and valves engineered to keep your system circulating the solar heat transfer fluid through the collectors and into the storage tank.

SunMaxx will size a pump station specific to your needs. No need to do the math!!!

Our pump station’s fill valve has GHT hose threads on the outside. You can easily make an adaptor using the following three fittings, which can be purchased at your local hardware store or plumbing supply.

  • Schrader valve x ¼” male NPT
  • Reducing Bushing, ½” NPT Male x ¼” NPT Female
  • Hose fitting, ½” NPT male x ¾” swivel GHT female

Use Teflon tape on the NPT threads of the Schrader valve and bushing in constructing the adaptor. When attaching the adaptor to the pump station, be sure to use two tools: one to hold the fill valve in place, and one to tighten the adaptor. That way, you won’t create leaks in the pump station itself while testing.

Take a deep breath and let all your air out… of your Solar thermal system One of the biggest issues with a successful commissioning is air removal. Any time you spend with this detail will be time well spent. Air pockets become entrained within your HTF and like to find places to hide. Air pockets can form between your HTF and the inner wall of piping (especially with flexible piping) and can only be removed through persistence and time. Here are a few things you can do to help this process. First, be sure that your air purger is located on the high and hot side of your collector series. The hotter the fluid the less the ability for dissolved gasses to stay in solution and the higher the air vent, the more likely you will effectively remove trapped air that, due to its buoyancy, will rise to the top. Once you feel most of the air has been removed this way, you can shut that air eliminator off or remove it all together. If you install a Titan Power Plus collector, you will have a manual air bleeder permanently installed in your line set connections. If you install a ThermoPower collector, you will include an air vent that should be isolated and de-commissioned at this point. Now, down to the pump station. The UniMaxx pump stations have an integral air eliminator with a scoop that will allow entrained air to collect and be bled off manually by opening the valve up to a full turn until HTF comes out. This can be done each day for the first few days or periodically checked. Smaller systems will take much less time removing the air. Another way of enabling the removal of air is to run the pump at maximum speed during commissioning, this will help to break the friction that holds the bubbles to the inner wall thus forcing the bubble through and out. After words, you should adjust your pump speed accordingly. If air persists in your system, it will inevitably find its way to the suction side of your pump and cause cavitation and eventual pump failure. If your pump appears to be not pumping, it is likely that although it is receiving 115v, it cannot pump because of air pockets. Simply unplug your pump and manual override and give it a few minutes. Air will work its way out, pump can run and then you need to go back to the air purging steps. Please view our SunMaxx technical manual (linked) for further instruction in effective system commissioning.

To check the temperature sensor you can use the digital multimeter tool and check the resistance of the sensor.

A simple steps which allow to check the temperature sensor:

  1. Turn the system off (electricity) – safety us the most important
  2. Open the controller box
  3. Check if the connection is not loose
    • If loose fix the connection by pushing the sensor wire inside the terminal
    • Close the controller box and check if that fixed the issue
  4. Check the sensor wire resistance with multimeter (turn the multimeter switch to the resistance measurement) – reading should be around 1.101 kOhm at room temperature and around 1.250 kOhm for hot water
    • If readings are different sensor might need replacement

This short advice should help you to solve the problem.

Available Solar Controllers

How to Order:

If you are confident with your solar hot water heating requirements you can place your order online by clicking on the add to cart button which is located above. All orders are reviewed by our solar hot water heating department and the customers are contacted in order to ensure that you have ordered the correct merchandise for your application. In the event you have any questions our sales staff are available from 8:30AM to 5:30PM EST.

Silicon Solar Inc ships products internationally please ask your sales representative for a shipping rate to your destination.

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.