Zone Damper Actuator
Check the Modular cable between the controller and the actuator.
Be sure both ends of the cable are fi rmly connected to the mating
connectors on the actuator and the VAV/Zone Controller. Be sure
the damper moves freely and is not bound. Do this by pressing
the actuator clutch button and rotating the damper shaft in both
directions to verify smooth operation. If binding is present, fi x
the problem as required. Remove power from the VAV/Zone
Controller. Reapply power and observe the damper rotation. If
the actuator does not drive the damper in both directions, the
actuator is probably defective or damaged. Another test that can
be performed is to swap cables with another known operating
actuator to determine if the cable could be bad. If the problem
goes away, you have a defective cable that must be replaced. You
can also try swapping a functioning actuator with the suspected
defective actuator. If this solves the problem, the defective actua-
tor will need to be replaced.
Diagnostics
VAV/Zone Controller Expansion Module
If the VAV/Zone Controller Expansion Module does not seem to
operate correctly, fi rst make sure the E-BUS cable between the
Expansion Module and the VAV/Zone Controller is fi rmly con-
nected at both ends. Be sure that the Expansion Module has been
confi gured correctly. The Expansion Module must be confi gured
using the Modular Service Tool SD, Modular System Manager
SD, or Prism 2 computer software for your application before it
will operate. You must confi gure the number of heat stages, and
if it is a fan terminal you must confi gure whether it is a Series
Flow or Parallel Flow Fan Terminal unit. On a single duct non-fan
terminal unit when a call for heat is initiated, the LED labeled
RLY2 should light up. If the Expansion Module is confi gured as a
fan terminal, on a call for the fan, the LED labeled RLY1 should
light up. If the LEDs do not light up, the Expansion Module is
probably defective and must be replaced.
40
VAV/Zone Controller Package
TROUBLESHOOTING
