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Question: 04-38 Code Section: Date: OBC Reference:

Question: If a thermostatic mixing valve is installed downstream of the hot water tank to regulate the hot water to the entire house to 120 degrees F. Do you still require a pressure balance shower faucet?

(On. Reg. 403/97) Sentence tells us that a pressure balanced faucet is NOT required provided the supply of hot water is controlled by a master thermostatic mixing valve conforming to CAN/CSA-B125.

The Ministry is cautioning inspectors and installers that not all mixing valves are certified as master thermostatic mixing valves and that if they are not then shower valves must be controlled by a pressure balanced valve or by a point of use mixing valve.

CSA further states that a distinction between a master thermostatic mixing valve and a point of use mixing valve is the master thermostatic must be tested to ASSE 1017 which are the same requirements as the CAN/CSA-B125.

P.S. Master thermostatic mixing valves are defined in the CSA document as : a device for controlling line water temperature in potable water systems and intended to be installed at the hot water source.

Interpretation: Approved at AMES

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