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Start-up
Performing system checkout
Bypass damper
1
Verify the VVT Bypass Controller is securely fastened to the bypass damper shaft and duct work.
2
Verify duct air temperature sensor is installed at the inlet of the damper or in the air source supply duct
upstream of the bypass damper connection.
3
Verify that the high pressure tubing from the controller's airflow (pressure) sensor is connected to the
duct static pressure probe downstream of the bypass damper. Then verify that the low pressure
connector is not blocked.
4
Calibrate damper and pressure sensor:
a)
Disable the air source heating, cooling, and fan outputs using one of the following methods:
• Physically disconnect the air source controller's output wiring to the unit.
• In the i-Vu® or Field Assistant tree, select the RTU Open controller. Go to Properties > Control
Program >
Configuration > Service Configuration > Service Test, then enable Service Test. Make sure all
other outputs under Service Test are disabled.
b)
Select the Bypass controller in the tree, then go to Properties > Control Program > Unit
Configuration > Bypass Control > Details tab.
c)
Click Damper Full Close, then verify that the damper is fully closed.
d)
Click Damper Full Open, then verify that the damper is fully open.
e)
Click Zero Cal to close the bypass damper and zero the pressure sensor. When Done appears, click
Apply.
f)
Enable the air source fan output using one of the following methods:
• Physically connect the air source controller's fan enable wiring at the unit.
• In the i-Vu® or Field Assistant tree, select the RTU Open controller. Go to Properties > Control
Program >
Configuration > Service Configuration > Service Test, then enable Fan Test. Make sure all
other outputs under Service Test are disabled.
g)
Select the Bypass controller in the tree, then go to Properties > Control Program > Unit
Configuration > Bypass Control > Details tab.
h) After the static pressure has stabilized, make sure that Target Damper Position and Duct Static
Pressure are not locked and that Target Damper Position is >0% and <100%. You may have to
adjust the Duct Static Pressure Setpoint slightly to get the damper within this range.
i)
Using a branch-tee, connect a magnehelic gauge to the High connector on the controller's airflow
sensor, then measure the static pressure. If the measured static pressure is different from the Duct
Static Pressure by ±.05 in. (+.012 kPa), click Pressure Sensor Cal, enter the measured value next to
the button, then click Apply.
j)
Remove the magnehelic gauge from the High connector, then reinsert the pressure tubing.
k)
Click Automatic Control to return the bypass to normal control.
VVT Bypass Controller
Installation and Start-up Guide
Carrier Proprietary and Confidential
18
CARRIER CORPORATION ©2017
All rights reserved
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