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Premium Commercial Controls
ERV
48
6.3.3.3 CW Mod: Chilled Water Modulating Coil
If this is a dual temp coil used for heating and cooling, see
Combined Tempering
.
The mode is determined by the outdoor temperature and the cooling lockout
temperature settings.
This type of cooling modulates a 0–10VDC chilled water valve using PI control. The KP and Ti
can be adjusted to fine tune the control. The NO4 cooling enable contact is engaged whenever
the cooling output is at 1% or higher.
The cooling status can be monitored in the
Unit Status
. The screen shows:
u
Cooling Control Variable which will be supply or return air, as selected
u
Cooling setpoint
u
Whether cooling enable 1 ON
u
Command (0–100%) to valve, where 0 = 10VDC output and 100% = 0VDC.
u
Cooling Status
TEMPERING CONTROL
The cooling status values are shown. Multiple values may be true.
MESSAGE
MEANING
Cool Locked Out by OA
The cooling OA lockout is lower than the OA temperature.
Lockout Overlap
The OA lockouts for heating and cooling overlap. (No vent mode).
The heating takes preference.
Econ Only
If economizer is open less than 100%.
Econ Mode
If in economizer mode.
Unit OFF
Unit is off.
