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Calefactio’s service valves kit is designed for tankless water heaters under 2 gallons. It combines two isolation valves including drains, a pressure relief valve, a union tee, and a port on the cold side for an expansion tank. The expansion tank function is to absorb the increased volume of water which results from the heating process, thereby keeping the system’s pressure below the relief valve setting. It also acts as a water hammer or shock absorber to absorb a sudden change in fluid velocity after the sudden closing of a faucet.

Documents &

Sale Sheet Submittal Data Instructions



  • Secure seal
  • Lead free
  • Facilitate maintenance with dedicated ports
  • Easy identification of hot and cold valves
  • Provided with 150 PSI pressure relief valve (PRV)


  • Water never comes in contact with the tank
  • No rust or corrosion of the steel shell
  • Strong welded construction
  • EPDM bladder without restriction
  • Resistant electrostatic paint finish
  • Factory precharge on all models

Technical data


#Model #Model Connexion Maximum température Maximum pressure
2 tankless water heater valves TK075NPT ¾” FNPT 180°F 150 PSI
1 pressure relief valve PRV075-150 ¾" MNPT 180°F 150 PSI
1 expansion tank PRV075-150 ½" MNPT (stainless steel) 180°F 150 PSI
1 union tee

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