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vav solutions

vav solutions

vav solutions

(OP)
I HAVE THE FOLLOWING QUESTION,  A NEW VAV SYSTEMS HAVE 5 FIVE BRANCH, BUT ONLY TWO HAVE VAV BOX, I DONT SEE PROBLEM WITH IT, BECUASE WHEN A VAV BOX CLOSE, THE STATIC PRESSURE IN THE DUCT INCREASE AND THE SENSOR INSTALLED 2/3 LENGHT OF THE DUCT SEND A SIGNAL TO THE PID CONTROLLER AND DECRESASE THE FRECUENCY AND THE SYSTEM WORK CORRECTLY.  

RE: vav solutions

Dynamics/duct shape might have an affect, but I think what you say is generally a pretty safe assumption.

RE: vav solutions

To evaluate what you are trying to accomplpish, you need to answer a few questions. Does the air handler fan run continuously? What controls heating or cooling mode? What happens if a non-VAV space is satisfied and a VAV space is not? What about the reverse? Is there re-heat?

RE: vav solutions

(OP)
THE AHU RUN CONTINOUSLY, AND WORK IN COOLING MODE, NEVER HEAT.  WE INITIALLY BALANCE THE SYSTEM WITH ALL BOX OPEN TO GARANTICE THAT THE AIR GO TO THE NON-VAV SPACE.  WE HAVE INSTALLED A PRESSURE SENSOR IN 2/3 OF DUCT.  IF ANY BOX CLOSE THE PRESSURE INCREASE AND SEND THE SIGNAL TO THE VFD, CONTOLLLING THE AIR INSIDE THE DUCT.

RE: vav solutions

(OP)
THIS SYSTEMS DONT HAVE RE-HEAT.

RE: vav solutions

I assume it okay for the three non-VAV spaces to be continuously cooled. If that's true then I don't see a problem. There's nothing magical about the 2/3 duct location for the pressure sensor. It simply a rule of thumb for a full VAV system. In your case, you need to make sure it's located in the duct trunk between the fan and the first VAV box.

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