Identifying your controller
The RESOL DeltaSol® BS/4 was the differential temperature controller fitted to a range of Australian solar hot water systems in its 1–2 sensor configuration. If your controller is labelled DeltaSol® BS/4 and was set up with one roof sensor and one tank sensor, this is your original part.
The RESOL DeltaSol® BS/4 is no longer manufactured. The current direct replacement is the RESOL DeltaSol® SLL, described below.
The RESOL DeltaSol® SLL is the current replacement controller for the RESOL DeltaSol® BS/4, BS/2, BS Plus, AX and AL. It is the smallest controller in the SL series, optimised for small and medium-sized solar thermal systems, with 2 pre-configured basic systems available. It offers automatic function control to the VDI 2169 directive and a V40 flowmeter input for heat quantity measurement. The tube collector function makes it suitable for both flat plate and evacuated tube collectors.
The DeltaSol® SLL supplied in Australia is a market-specific version, confirmed by RESOL. It does not include a thermal disinfection function, an SD card slot, or VBus RPT remote parameterisation. If your existing controller uses any of these, please contact us before ordering.
RESOL DeltaSol® SLL — Specification
- Relay outputs: 2 semiconductor relays, 1 A each, 2 A total at 240 V
- Sensor inputs: 4, for Pt1000, Pt500 or KTY sensors
- Flow input: 1 x V40 impulse input for heat quantity measurement
- PWM outputs: 2, for high-efficiency pump speed control
- System layouts: 2 pre-configured
- Function control: automatic, to VDI 2169
- Tube collector function: yes — suits evacuated tube and flat plate
- Thermostat function: yes
- Data interface: VBus®
- Power supply: 100–240 V, 50–60 Hz
- Ingress protection: IP 20 — indoor, dry location only
- Ambient temperature: 0 to 40 °C
- Dimensions: 110 x 166 x 47 mm. Mounting centres 130 mm
What you receive: the RESOL DeltaSol® SLL 1-2 sensor controller, supplied with two new sensors — one 20m roof sensor and one tank sensor. New sensors are always supplied with a replacement controller and must be fitted at the same time. Reusing existing sensors with a new controller voids warranty.
