WattMaster VAV System - Manual (Page 19)

Operator Interfaces
Technical Guide
19
Setpoint Screen #15
WMVAV Spts ID 59
Relief Spt..: x.xx”
Deadband....: x.xx”
The WMVAV controller uses the Relief Fan VFD signal to maintain the
Relief Spt value plus or minus the Deadband value. Adjustments to the
signal are made at a rate equal to the Control Rate setpoint on the
previous Static Pressure screen. If you don’t require relief pressure con-
trol, simply ignore these settings.
Description Minimum Default Maximum
Relief Spt -0.20” WG 0.10” WG +0.20” WG
Deadband 0.01” WG 0.02” WG 0.10” WG
Setpoint Screen #16 & 17
WMVAV Spts ID 59
Set SAT Cool Reset
VLT=0V Spt=55
VLT=10V Rst=55
WMVAV Spts ID 59
Set SAT Heat Reset
VLT=0V Spt=140
VLT=10V Rst=140
These screens allow you to set values for resetting the supply air tem-
perature when the unit is in cooling and/or heating mode. You can
configure the HVAC unit to reset the supply air temperature setpoint
based on the Outdoor Air Temperature, Input Voltage Signal, Space
Temperature, Return Air Temperature or Fan VFD Percentage. These
are the reset values that cause the supply setpoint to reset from its
minimum to its maximum value. Please note that the Supply Air
Setpoint value (Spt) must be set using Setpoint Screen #4 and cannot
be changed from this screen.
*Space temperature setpoints are 74 COOL, and 72 HEAT
Space Temperature Cool Reset Example:
Space Temperature (SPC) = 76 F SAT Setpoint (Spt) = 55 F
Space Temperature (SPC) = 74 F SAT Setpoint (Rst) = 65 F
Space Temperature Heat Reset Example:
Space Temperature (SPC) = 72 F SAT Setpoint (Spt) = 90 F
Space Temperature (SPC) = 70 F SAT Setpoint (Rst) = 120 F
VFD Percentage Cool Reset Example:
VFD Percentage (VFD) = 70% SAT Setpoint (Spt) = 55 F
VFD Percentage (VFD) = 30% SAT Setpoint (Rst) = 65 F
VFD Percentage Heat Reset Example:
VFD Percentage (VFD) = 30% SAT Setpoint (Spt) = 90 F
VFD Percentage (VFD) = 70% SAT Setpoint (Rst) = 120 F
Input Voltage Cool Reset Example:
Input Voltage (VLT) = 0 Volts SAT Setpoint (Spt) = 55 F
Input Voltage (VLT) = 10 Volts SAT Setpoint (Rst) = 65 F
Input Voltage Heat Reset Example:
Input Voltage (VLT) = 0 Volts SAT Setpoint (Spt) = 90 F
Input Voltage (VLT) = 10 Volts SAT Setpoint (Rst) = 120 F
Setpoint Screen #18
WMVAV Spts ID 59
Start Fan Delay
Timer...:10 Sec
This is the amount of time that the main HVAC unit fan will delay
before starting after an occupied signal is initiated or after a power fail-
ure. The default value is 999. With the default value the delay will be
equal to the unit address multiplied by 5.
Example: Controller ID (address) 18 would cause a 90 second delay
when the default value of 999 is used. Controller ID (address) 30 would
cause a 150 second delay when the default value of 999 is used.
Description Minimum Default Maximum
Timer 0 Sec 999 Sec 999 Sec
Setpoint Screen #19
WMVAV Spts ID 59
Mechanical Heat/Cool
Failures Occur After
No Change For xxx M
Once a heating or cooling stage is activated, the Supply Air must change
accordingly by 5° before this amount of time elapses, or a mechanical
failure is assumed and an alarm is generated.
Description Minimum Default Maximum
Alarm Delay 0 Min. 15 Min. 300 Min.