Tempering/Mixing Valve Operation

[GSSFC]

I am installing a new hydronic radiant heating system in the addition of my house. I am comfortable doing the work, I just have a question about how the mixing valve works.

Is the maxing valve variable or static operation. I ask, because the supply temperature from the boiler is relatively constant at 180*F. The return temperature of the radiant system will of course vary. If I utilize the return water to temper the supply water down to 120*F, will the tempered water temperature always be 120*F even if the return water temp is 80*F or 110*F?

Hope that makes sense! Thanks in advance.

Thanks, Tim

 

[Ezzie]

The mixing valve operates as a temperature regulator that prevents the output from exceeding a temperature point that it is set for. Depending on which valve you have, they are usually adjustable. Normally there is a cold water in on one side, a hot water in (from boiler) on the other side and the output is a blend of the two at the desired max. temp.

In your design, is it a closed loop system or an open loop system? If closed loop, the "cold" would be in the return side coming from the floor.

 

[GSSFC]

The mixing valve operates as a temperature regulator that prevents the output from exceeding a temperature point that it is set for. Depending on which valve you have, they are usually adjustable. Normally there is a cold water in on one side, a hot water in (from boiler) on the other side and the output is a blend of the two at the desired max. temp.

In your design, is it a closed loop system or an open loop system? If closed loop, the "cold" would be in the return side coming from the floor.

Hi Ezzie,

It is a closed loop system, and I understand where the cold supply would come from.

My question, is will the tempered water output temperature be constant even if the cold water supply temperature varies?

Thanks, Tim

 

[nate379]

Temp doesn't hold the same on mine.

 

[duaneb9729]

the short answer is yes