UniMaxx™ Solar Pump Station Booster Pump

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The Star 30 with a 1 ½” union is an advanced replacement pump for SunMaxx’s UniMaxx™ solar pump stations. Its unique design allows the connection of two pumps in series, making it ideal for drain back systems or situations requiring higher pumping head & capacity. This pump operates efficiently within a wide temperature range and delivers impressive performance under various conditions. Its durable construction, low power consumption, and easy installation make it a cost-effective solution for your solar hot water system, reducing both time and costs associated with maintenance.

SKU: UniMaxx-Plus-SC-S30-B Category:


Solar Pump Station Booster Pump

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.

The Star 30, equipped with a 1 ½” union, is the standard replacement pump for SunMaxx’s UniMaxx™ solar pump stations. This variant allows for the connection of two pumps in series, commonly used in drain back systems or systems that require more pumping head & capacity.


  • Replacement pump suitable for solar systems
  • Threaded connection: 1 1/2IN
  • Model: Wilo Star S30 U25
  • Permissible temperature range: -14°F to 230°F
  • Mains connection: 115/120 V, 60 Hz
  • Protection class: IP 44
  • Max. operating pressure: 145 PSI
  • Power consumption: 1/10 HP
  • Max. Amperage: 1.08A
  • Pump Materials: Pump housing – Grey cast-iron, Impeller – Polypropylene, Shaft – Stainless steel insulation – EPP, Fittings – Brass, Seals – Viton/teflon, Bearing – Carbon

Product Highlights The Star 30 with a 1 ½” union is a specially designed replacement pump. It enables the connection of two pumps in series, enhancing pumping head & capacity, particularly for drain back systems.

Adopt the Star 30 with a 1 ½” union for your solar pump station. This advanced replacement pump will deliver superior pumping capacity, reducing downtime and maintenance costs in your solar hot water system.

Product Description

The Star 30 is the standard booster pump for SunMaxx’s UniMaxx™ solar pump stations.  Adding the booster pump will increase the pressure of fluid flow in the system. These pumps also guaranteed to fit and work properly with your SunMaxx solar hot water system.

List of components

1) 1½” male union thread
2) 1½” union nut
3) 3 speeds asynchronous motor inside a housing
(degree of protection : IP44)

Features & Benefits

  • 3 different speeds options available
  • Two pumps may be used when additional head pressure is needed
  • Ideal for small commercial and large residential solar hot water and heating systems
  • UniMaxx Pump Skids are built with Wilo Star S30 U25 pumps
  • flows up to 30 GPM
  • Larger, custom pump systems are available upon request

Technical Details


  • Model: Wilo Star S30 U25
  • Permissible temperature range: -14°F to 230°F
  • Mains connection: 115/120 V, 60 Hz
  • Protection class: IP 44
  • Threaded connection: 1 1/2”
  • Max. operating pressure: 145 PSI
  • Power consumption: 1/10 HP
  • Max. Amperage: 1.08A

Pump Materials:

  • Pump housing: Grey cast-iron
  • Impeller: Polypropylene
  • Shaft: Stainless steel insulation – EPP
  • Fittings: Brass
  • Seals: Viton/teflon
  • Bearing: Carbon

Below, the pressure drop characteristic of UNIMAXX-PLUS-SC-S30-R solar pump, which is the heart of the solar hot water pumping system, is presented:

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.

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System Charge Kit

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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.