RESOL BS/4 Solar Hot Water Complete Pump Station
Complete solar hot water pump station for open loop solar hot water systems. Includes everything needed for a full pump station replacement in one order:
The RESOL DeltaSol® SLL is the current replacement for the DeltaSol BS/4. It provides the same core differential temperature control with improved reliability and ongoing manufacturer support.
Replacing the complete pump station is often more economical and efficient than replacing individual components. All components are matched to work together, reducing installation time and improving reliability.
Suits a wide range of Australian open loop solar hot water systems including Apricus, Hills, Dux, Chromagen, Bosch and systems previously running Resol or Senztek controllers.
The original DeltaSol BS/4 has now been replaced by the updated SLL model, which provides the same functionality with improved reliability and ongoing support.
It is best suited to systems where precise control, multiple sensor inputs or more advanced setup options are required.
This is a complete solar hot water pump station replacement, not just a controller or pump.
If your solar hot water system is not working correctly, the pump station or controller is often the cause. This unit restores reliable circulation and temperature control for efficient system performance.
COMPLETE SYSTEM SOLUTION - Commonly used by plumbers and solar technicians for reliable system repairs.
✔ What this pump station includes
- Grundfos 15-20 CIL2 circulating pump
- RESOL DeltaSol® SLL controller (replaces BS/4, BS/2, BS Plus, AX and AL) — 3 sensors (roof, tank and inlet)
- AVG or AW pump unions
- AVG or AW solar-rated non-return valve
- AVG flow meter
- UV stabilised full enclosure cover — wall mount or tank side mount
- Thermal heat paste and roof sensor joiners
All components are matched to work together, reducing installation time and improving reliability.
✔ Common signs your pump station needs replacing
- No hot water or poor heating
- Pump not running
- System not circulating
- Controller not responding
- Intermittent or unreliable operation
✔ About the Resol controller
Resol controllers are widely used in solar hot water systems and are known for their reliability and advanced control features.
The DeltaSol range offers flexible system configurations, multiple sensor inputs, and precise control of circulation for efficient heat transfer.
This allows more precise system control and improved heat transfer compared to standard controllers.
✔ When this pump station is suitable
- Replacing an existing pump station
- Pump or controller failure
- Systems requiring full upgrade
Ideal for replacing older or faulty pump stations in residential solar hot water systems with improved efficiency.
✔ When it may NOT be suitable
- Systems requiring controller-only replacement
- Heat pump systems
- Electric booster-only issues
This allows better system performance, improved heat transfer, and reduced reliance on electric boosting. 👉 If you’re unsure, this Resol version is the best choice for systems requiring flexibility and long-term reliability.
✔ Controller Options: Aestiva vs Resol vs Senztek
We offer this pump station with different controller options depending on your system requirements:
- Aestiva: modern differential controller with smart heat management features, including overheating and stagnation protection. Ideal for users wanting advanced protection and efficient system performance.
- Resol: highly configurable controller suited to a wide range of system layouts, with flexible programming and multiple sensor inputs. Best for more complex or customised systems.
- Senztek: simple, reliable and widely used replacement controllers. Ideal for straightforward system repairs and standard solar hot water setups.
If you are unsure which controller is best for your system, contact us and we can help you choose the correct option.
✔ Compatible systems
Commonly used in:
- Apricus
- Hills
- Dux
- Chromagen
- Bosch
- Systems using Resol or Senztek controllers
**The RESOL DeltaSol® SLL controller is the replacement controller for the Resol DeltaSol BS/4, BS/2, BS Plus, AX and AL controllers.**
- Microbuttons for quick access to the manual mode and the holiday function
- 3 relay outputs (incl. 1 potential-free extra-low voltage relay)
- 4 inputs for Pt1000, Pt500 or KTY temperature sensors
- 1 V40 impulse input
- 2 PWM outputs for the speed control of high-efficiency pumps
- 10 basic system layouts to choose from
- Automatic function control according to VDI 2169
- Heat pump demand (optional)
- Solar Hot Water Parts stock complete replacement pump stations for solar plumbing repairs. Sometimes its more economical and efficient to replace everything with a much more up to date selection of products. The advantage with some of the better quality controllers on the market is that they have visible temperature readings which makes it possible to monitor your systems to detect/prevent possible problems. By adding a quality controller to a complete covered pump station, with the best circulating pump and valves on the market, you have upgraded your systems efficacy and have good peace of mind your system will be working to its best potential.
