WattMaster VAV System - Manual (Page 18)

Technical Guide
Operator Interfaces 18
Setpoint Screen #13
WMVAV Spts ID 59
Economizer Setpoints
Min Position.: xx %
Control Rate.: xx
If the Economizer is not enabled or currently required during the occu-
pied mode of operation, the outside air dampers will maintain the Min
Position setpoint to provide ventilation into the space.
The Control Rate can be used to speed up or slow down the operation
of the outside air dampers to prevent hunting. Unless you actually wit-
ness this damper hunting it is not recommended that the Control Rate
value be changed. Large values speed up the damper, and small values
slow down the damper.
Description Minimum Default Maximum
Min Position 0 % 10 % 100 %
Control Rate 10 90 99
Setpoint Screen #14
WMVAV Spts ID 59
Static Spt..: x.xx”
Deadband....: x.xx”
Control Rate: xx Sec
The WMVAV controller uses the Fan VFD signal to maintain the Static
Spt (duct static pressure) value plus or minus the Deadband value.
Adjustments to the signal are made at a rate equal to the Control Rate
setpoint, which can be used to speed up or slow down the signal to
prevent hunting.
Description Minimum Default Maximum
Static Spt 0.10” WG 0.50” WG 3.0” WG
Deadband 0.01” WG 0.10” WG 1.0” WG
Control Rate 1 Sec 10 Sec 30 Sec
Setpoint Screen #10
WMVAV Spts ID 59
Heating Stages Off
If Supply Fan VFD Is
Below:.........: xx%
If the Supply Fan VFD drops below this value, the heat will stage off.
The Supply Fan VFD will not be allowed to drop below this value while
the unit is in Heating Mode unless the static pressure rises 0.5” above
the static setpoint.
Description Minimum Default Maximum
Below SP 0 % 30 % 100 %
Setpoint Screen #11
WMVAV Spts ID 59
Pre-Heat Output ON
Continuous Below OAT
Level........: xx
° F
If your air handler has at least one heating stage and you require a low
ambient protection or preheating of the air stream, you can enter a sup-
ply temperature value that causes one stage of heating to come on and
remain on continuous if the outdoor air drops below this level. If you
don’t want this protection do not configure any relays for this function.
Description Minimum Default Maximum
Low Ambient Level -50
°
F 0
°
F 70
°
F
Setpoint Screen #12
WMVAV Spts ID 59
Economizer Setpoints
OAT/WB Enable: xx
° F
If the Outdoor Air Temperature drops below the OAT/WB Enable
(Outdoor Air Temperature or the optional Wetbulb Temperature, if
it’s available), the Economizer will be enabled to operate as the first
stage of cooling anytime there is a demand for cooling. If the econo-
mizer is currently in a control mode, it will attempt to maintain the
Supply Air Temperature at the Supply Air Cooling Setpoint.
Description Minimum Default Maximum
OAT/WB Enable -30
°
F 55
°
F 80
°
F
Programming The WMVAV Controller