Solar Thermal Information

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Product range
Code 255050A Dual line pump station, 3 speed, flow and return connection, flow meter scale: 1/2–5 gpm 3/4" female
Code 255056A Dual line pump station, without pump, flow and return connection, flow meter scale: 1/2–5 gpm 3/4" female
Code 256050A Single line pump station, 3 speed, return connection, flow meter scale: 1/2–5 gpm 3/4" female
Code 256056A Single line pump station, without pump, return connection, flow meter scale: 1/2–5 gpm 3/4" female
CALEFFI
Solar pump stations
series 255 & 256
Function
Solar pump stations are used on the primary circuit of solar heating
systems to control the temperature of the hot water storage.
The pump inside the unit is activated by the signal from a differen-
tial temperature controller. The unit contains the functional and
safety devices for an optimal circuit control, and is available with
both flow and return connection or with return connection only.
General
The solar pump station is a pre-installed and leak-tested unit with
fittings for transferring heat from the collector to the storage tank.
It contains important fittings and safety devices for the operation of
the solar thermal system:
• Ball valves in flow and return in combination with check valves
to prevent gravity and thermo circulation.
• Ports for flushing, filling and emptying the system.
• Air vent for manual bleeding of the solar thermal system.
• Flow meter for displaying and setting the flow rate.
• Thermometer in flow and return for displaying
both temperatures.
• Pressure gauge for displaying the system pressure.
• Safety relief valve to prevent overpressure.
• Three-speed solar pump for wide range of flow rates.
Technical specifications
Body: brass
Temperature gauge: steel / aluminium
Seals: PTFE / EPDM
O-Rings: EPDM / Viton
Union gaskets: AFM 34, asbestos free
Insulating shell: EPP, thermal conductivity value = R4
Performance
Medium: water, glycol solutions
Max. percentage of glycol: 50%
Max. working temperature: 360°F (180ºC)
Max. working pressure: 150 psi (10 bar)
Safety relief valve temperature range: -20 to 360°F (-30 to 180ºC)
Safety relief valve factory setting: 90 psi (6 bar)
Min. opening pressure for check valve: Δp: 1/4 psi (2 kPa)
Adjustment range of flow meter: 1/2 to 5 gpm (1 to 20 l/min)
Max return flow meter temperature: 265°F (130ºC)
Pressure gauge scale: 0–90 psi (0—6 bar)
Temperature gauge scale: 32–320°F (0—160ºC)
Connections: 3/4" female straight thread
Filling/drain hose connections: 3/4" male hose thread
Expansion tank connection: 1/2" male straight thread
Pump
Wilo solar model: Star S-16 U15
Body: cast iron
Power supply: 115 V - 60 Hz
Max. pressure: 150 psi (10 bar)
Max. temperature: 230°F (110ºC)
Agency approval: cULus
Wilo Star S-16 U15 hydraulic characteristics