Pressure Line Connections For Vav - York Sun Select YV28 Manual

Figure 28: Completed exhaust air hood assembly
Item Description
A Exhaust air hood assembly

Pressure line connections for VAV

About this task:
For VAV unit operation, field setup of the pressure
lines is required to obtain readings of the supply
duct pressure and building space pressure. Follow
the instructions below to complete this setup.
1. Open the control panel access door. The
duct pressure sensor (DPS) is located on the
mounting plate in the bottom right corner of
the control box as shown in Figure 29.
Figure 29: DPS location
22 Installation Manual: YORK Sun™ Select YV28 to YV50
®
Johnson Controls Ducted Systems
Item Description
A Duct pressure sensor
B Control panel door
2. For best results, use a pressure-transmitting
tubing with 3/16 in. I.D. for tubing lengths of
up to 100 ft, 1/4 in. I.D. for tubing lengths up
to 300 ft, and 3/8 in. I.D. for tubing lengths up
to 900 ft.
3. Drill a hole in the knock-out in the bottom
of the control box shown in Figure 30. Drill
the hole in a size that fitd both the building
pressure and supply-air pressure tubes. Use
protective measures to ensure that the tubing
does not develop a cut from contact with any
sharp edges.
Figure 30: Knock-out location
Item Description
A Knock-out for pressure tubes
4. Determine the length of tubing required
to run from the DPS (identified in Step 1),
down through the hole in the knock-out in the
bottom of the control box, and to the desired
location for obtaining the building pressure.