CAUTION
Do not cross 24VAC and 24VDC wiring on EVFDR relay.
VAV units
Differential pressure transducer
Figure 1: Label on unit/VFD for VAV with pressure transducer
For VAV option units, the differential pressure transducer (0-5" W.C) is factory wired and mounted
inside the VFD control box. The transducer senses gage pressure (static) and converts this pressure
difference to an analog signal. The unit is wired for 0–5VDC output for DSV, DSH, or CSV C-gen
units.
The transducer is supplied with two 1/4-inch OD pressure fittings and accepts field provided 1/4-
inch push-on tubing for lengths of up to 300 feet. The positive (HIGH) and negative (LOW) pressure
ports are indicated on the transducer. Connect unit RETURN AIR tubing to negative (LOW) fitting
and SUPPLY AIR tubing to positive (HIGH) fitting.
Note:
Do not enter Setup mode when powering on the VFD.
Do not change parameters 4009 and 4011 for the VAV option on DSH, DSV, or CSV C-gen units.
These 2 parameters are used for B-gen units only (Simplicity 1A, not SEC.)
For these units, use the Smart Equipment (SE) controller to set the VAV setpoint.
CAUTION
Do not adjust the VFD setpoint to greater than the maximum design pressures of the duct system or
the unit.
Note:
•
Only use 24VAC from SE controller to the differential pressure transducer (Term. Exc.)
VFD for D-Series (DSV/DSH) Air-cooled Self-Contained Units, and C-Series (CSV) Water-Cooled Self-Contained Units,
C-Gen
10
Johnson Controls
