• Caleffi Solar Expansion tank - 5 gallons - 259018

    - 3/4 inch straight thread connection

    Product ID • CAL259018000

  • $82.75
  • Quantity:
  • Free Shipping Eligible


Caleffi Solar Expansion Tank 5 gallons - 259018 is used for solar hot water heating systems using flat panels or Evacuated Tubes.

Modern solar heating systems can reach temperatures of up to 385°F during inactivity. The result is the vaporization of the solar liquid and extreme temperatures in the solar circuit, up to the solar station. This damages parts of the system, including pumps, connection joints and the diaphragm in the expansion tank. Furthermore, in the event of prolonged heat absorption, for example in the summer, when on vacation or if the electricity is out, the pressure of the solar systen can increase to the point of activating the safety relief valve. In order to support the highest possible inactivity temperatures, the special heat-resistant diaphragm in the Caleffi SolarPlus 259018 expansion tank can withstand temperatures up to 210°F.

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Manuals & Docs

Technical Specs

Caleffi Solar Expansion Tank 5 gallons - 259018 Techs and Specs

  • Capacity
    5 gallons
  • Body
    Welded Steel
  • Connection
    3/4 inches Male Thread
  • Coating
    Epoxy paint
  • Diaphragm
  • Solutions Medium
    Water and/or glycol
  • Maximum percentage of glycol
  • System temperature range
    32 to 250°F
  • Maximum diaphragm temperature
  • Maximum working pressure
    150 psi
  • Pre-charged pressure
    35 psi
  • Weigth
    17.4 pounds

Info & Links

Solar Heating and Solar Domestic Hot Water with Flat Panels Example

Solar Heating / Solar Domestic Water with Evacuated Tubes and Boiler Example

Solar Domestic Hot Water, Solar Heating and Solar Pool Heating with Flat Panels

Solar Domestic Water with a Water Heater as a Backup Heat Source Example

Solar Panels for Domestic Water and Space Heating with a Boiler as the Backup Heat Source Example

Solar Panels for Domestic Water and Space Heating Pre-Heating into a Gas Combination Boiler Example

Solar Space Heating with a Backup Gas/Electric Boiler Installation Diagram

Hot Water Output examples for 3 locations

Solar Hot Water System Install - Waitsfield Vermont

Solar Hot Water System Install - Maine

Solar Hot Water System Install - Upstate New York

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