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pneumatic versus electromechanical controls

a regular supplier such as Johnson Controls, Automated Logic, Invensys, Siemens, etc? Each can give you a sampling of their controllers and requirements.

Most VAV box controllers are fairly standard affairs these days, with integrated motors and control boards. DDC or straight electric/electronic versions are available.

You may (may) be able to salvage the flow-cross volume pick-ups but the k-factors have to be known for programming purposes.

Most of the sequences are "canned" (pre-programmed into the board) being so common.

The controllers I see are field-installed on factory-naked boxes whereas in years past the controllers were shipped to the VAV box factory for installation there. This should tell you that field adaptation is commonly done.

The controllers I see also have integrated damper motors and so slide over the shaft. Knowing the shaft diameter, round or flat and other characteristics is helpful.
"If you do not know the answer, say, "I do not know the answer", and you will be correct!"

-Ernie White, my Dad


  • jhansen
    jhansen Member Posts: 59
    converting pneumatic controls

    i have a custoomer that we have been servicing their hvac system including aa honeywell pneuamatic control system. due to many inoperative vav boxes they requested i put together a quote for converting from pneumatic to electromechanical control system and upgrading the vav boxes. where do you suggest i start collecting my information from. and any other input would be appreciated.

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