Honeywell W7752D Manuale Utente

 

 EN2B-0285GE51 

R0909 

13

 

 

 

Excel 10 FCU Controllers can operate with either two-pipe or 

four-pipe systems. A two-pipe system requires a changeover 

input to the controller (hardware or network input). 

 

Excel 10 FCU Controllers can operate with a variety of 

actuators for heating and cooling equipment. Floating 

actuators can be used; this requires that the valve run time be 

specified during configuration of the controller. 

 
The actuator runtimes can be configured in the range 20 sec 
to 600 sec in steps of 1 second. 
 
Valves will be synchronized by driving the valve fully closed 
(150% of the valve run time) under the following conditions: 
 
•  whenever the control level reaches 0% or less; 
• at 

power-on; 

•  whenever the occupancy status changes to a lower mode, 

e.g., from occupied to standby or unoccupied; 

•  when synchronization has not taken place within the last 

24 hours. 

 
Once synchronization has been completed, the output control 
will be returned to the normal control loop. 

 

Valve action can be configured as either direct or reverse. 

When in a two-pipe system with a changeover input, a floating 

actuator can be used which has the middle position (50%) as 

the zero energy position. The cool range is then 0 to 50% and 

the heat range 50 to 100%. The output must be configured as 

floating-mid. 

 

Multi-stage systems can be controlled with up to three 

different stages of heating/cooling control. Switching levels 

are specified in % of control level (see Fig. 10) as is a 

hysteresis setting which applies to all switching levels. 

Heating and cooling switching levels and hysteresis are 

specified separately. Min. OFF times can be configured, and 

for one-, two- and three-stage systems, a min. ON time can 

also be configured. 

 

PWM electronic valves and thermal actuators can also be 

connected and can be configured as either direct or reverse 

action. The cycle time must be specified during configuration. 

In the case of PWM valves, the zero and full positions must 

also be configured. 

 

Additionally, the W7754K1001 features an extra socket 

(located to the left of the terminal blocks) containing a digital 

output suitable for connection to a solid-state relay employed 

for low-voltage PWM control in high-current electric reheat 

applications.