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FORM 160.54-M1
ISSUE DATE: 10/25/2019
• Control Valve Output Settings:
a. TYPE – Makes the control signal to the Heat
Recovery Control Valve either 0 to 10 VDC
or 4-10mA (default 0 to 10 VDC).
b. PID OUTPUT – Makes the control signal to
the Heat Recovery Control Valve either Di-
rect or Reverse acting (default Direct). Set to
Direct for this application.
c. SET – Is used to manually set the Heat Re-
covery Control Valve to any position be-
tween 0.0% and 100%.
d. AUTO – Returns the Heat Recovery Control
Valve to Automatic Control Mode (default
Auto).
• Hot Water Control – Sets the proportional gain of
the control:
P – Sets the proportional gain of the control
over the range of 0.00 to 5.00(default 2.00)
I – Sets the integral gain of the control over
the range of 0.0 to 5.00 (default 2.00)
D – Sets the derivative gain of the control
over the range of 0.0 to 5.00 (default 0.00)
Hot Water Setpoint
Leaving Heating
Condenser Water
Temperature
FIGURE 93 - PID CONTROLLER DIAGRAM
JOHNSON CONTROLS
+
PID
Error
Control
-
P
I
(PID Gains)
JCI COMPANY CONFIDENTIAL
• Remote Input Type – Configures the LTC I/O
Board input (TB9-3/4) to accept either a 0-10
VDC or 4 to 20mA input signal type for the Re-
mote Hot Water setpoint input.
When Hot Water Control is active, the Control Valve
Output is modulated by a direct acting PID control.
The inputs to the PID control are the Leaving Heat-
ing Condenser Water Temperature and the Hot Water
setpoint (the Active Hot Water setpoint displays the
setpoint in use). The PID control error is defined as
(Hot Water setpoint – Leaving Heating Condenser Wa-
ter Temperature). The PID control's proportional, inte-
gral and derivative gains are programmable using the
CHANGE SETPOINTS key. The Control Valve posi-
tion is displayed as 0.0% to 100% in the box labeled
CONTROL VALVE OUTPUT. The control output to
the valve is Direct Acting (when the Leaving Heating
Condenser Water Temperature rises above the Hot Wa-
ter Setpoint, the valve is driven more open to provide
greater cooling to the standard lower tube bundle). The
following diagram shows the PID controller.
Analog
PID Control
Output
Output
Conditioning
(0.0–100.0%)
D
Type
(0-10V,
4-20mA)
SECTION 28 - HEAT RECOVERY
Analog
Output
(0-10V,
10-0V,
4-20mA [2-10V],
20-4mA [10-2V])
Output
(Direct,
Reverse)
LD27941
239
28
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