The RESOL controller for standard Solar Thermal Systems including BS/2, BS/4 and BS PLUS controllers

Includes a heat dump function, drainback functionality including a booster function, and more.


    • Drainback option
    • Heat quantity measurement
    • Function control
    • Commissioning menu
    • Unit °C and °F selectable
    • HE pump control via adapter

DeltaSol® BS/4, BS Plus

    • 3 basic system layouts (DeltaSol® BS/4), 10 basic system layouts (DeltaSol®BS Plus) to choose from
  • Tube collector function, thermal disinfection function, time-controlled thermostat function

Technical Data:

Inputs: 4 Temperatursensoren Pt1000
1 semiconductor relay (DeltaSol® BS/2), 2 semiconductor relays (DeltaSol® BS/4, DeltaSol® BS PLUS )
Switching capacity: 1 (1) A 240 V~ (semiconductor relay) 
Total switching capacity: 
1 A 240 V~ (DeltaSol® BS/2)
2 A 240 V~ (DeltaSol® BS/4, DeltaSol® BS Plus)
Power supply: 100 ... 240 V~ (50 ... 60 Hz)
Supply connection: type Y attachment
0,45 W (DeltaSol® BS/2)
0,74 W (DeltaSol® BS/4)
0,38 W (DeltaSol® BS Plus)
Temperature controls class: I (DeltaSol® BS/4, DeltaSol® BS Plus)
Energy efficiency contribution: 1 % (DeltaSol® BS/4, DeltaSol® BS Plus)
Mode of operation: type 1.C.Y action
Rated impulse voltage: 2.5 kV
Data interface: RESOL VBus
® current supply: 35 mA
Functions: differential temperature controller with adjustable system functions: function control according to BAFA guidelines, operating hours counter, tube collector function (DeltaSol® BS/4, DeltaSol® BS Plus), heat quantity measurement and pump speed control
Housing: plastic, PC-ABS and PMMA
Installation: wall mounting, mounting into patch panels is possible
Indication/Display: System-Monitoring-Display for visualization of systems, 16-segment and 7-segment display, 8 symbols for indication of system status and operating control lamp
Operation: 3 push buttons at the front
Ingress protection: IP 20 / EN 60529
Protection class: II
Ambient temperature: 0 ... 40 °C / 32 ... 104 °F
Pollution degree: 2
Dimensions: 172 x 110 x 49 mm / 6.77" × 4.33" × 1.92"

default BS/4 - Technical Product Brief (1.18 MB)

default BS/4 - Installation & User Manual (2.96 MB)

Free Resol DeltaSol BS/2-V2

CTUVUS Certified

Free Resol DeltaSol BS/4-V2

CTUVUS Certified

Free Resol DeltaSol BS PLUS-V2

CTUVUS Certified



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