Installation
TRANSDUCER PNEUMATIC TUBING
Static Pressure Control Plastic Tubing (Pneumatic Tubing)
Duct static transducers (all VAV units) and any unit with an optional building pressure control transducer, require pneumatic tubing to be field supplied and installed. Both the duct static transducer (VAV only) and optional building pressure transducer are mounted behind the right hand damper door. All wiring from the transducers is factory installed.
Duct Static Transducer
Plastic tubing (3/16" ID) must be run from the high pressure tap of the transducer to a static pressure tap (field supplied) in the supply duct, located at a point where constant pressure is desired. This is normally 2/3rds of the way down the duct, before the first take off.
Building Pressure Transducer
Plastic tubing (3/16” ID) must be run from the high pressure tap of the building static pressure transducer to a static pressure tap (field supplied), located in the conditioned space. The tap should be placed in a location where over pressurization will cause a problem, for example, in the lobby area where excessive pressure will cause the doors to remain open. The tap should never be placed above the ceiling.
Static Pressure Probe Installation
On units with duct static transducers (VAV units) and any unit with an optional building pressure, a factory supplied Static Pressure Probe must be field installed at the top of the rear corner post on the unit - see Figure.
The factory supplied atmospheric pressure probe and associated mounting hardware are shipped inside the unit control panel. The hardware consists of a mounting bracket and a short section of pneumatic tubing. The pneumatic tubing must be field installed from a factory pressure tap (next to the mounting location for the static pressure probe) to the atmospheric pressure probe (see Installation Instructions, Form XXX.XX- XX).
FORM
If the unit is equipped with both a building pressure transducer and a duct static transducer, a “tee” will be factory installed, and both the Duct Static Pressure Transducer and building pressure will be connected to the “tee” - both building static pressure transducer and duct static transducer will use the same factory supplied atmospheric pressure probe.
The “low” side connection of the duct static or building pressure trans- ducers are shipped with the pneumatic tubing factory installed and routed, to the external factory pressure tap.
42 | JOHNSON CONTROLS |
