Johnson Controls YORK YK MaxE, Operation Manual

Page: 29 / 184

FORM 160.54-O1
29
JOHNSON CONTROLS
2
delta p
Displays the pressure difference between the condenser
and evaporator (condenser minus evaporator). This is
also called the Head Pressure. Only appears when Head
Pressure Control is enabled.
head pressure setpoint
Displays the active Head Pressure Setpoint to which the
head pressure is being controlled. Only appears when
Head Pressure Control is enabled.
heating Condenser Liquid flow switch (Led)
Displays the status of the flow switch in the heating
condenser tube bundle. Illuminates when liquid flow is
present. Otherwise, it is extinguished.
Condenser Liquid flow switch (Led)
Displays the status of the flow switch in the standard
condenser tube bundle. Illuminates when liquid flow is
present. Otherwise, it is extinguished.
pid Control Mode
Only appears when Hot Water Control is enabled.
Displays the function the Control Valve is controlling.
If the chiller is equipped with both Heat Recovery and
Head Pressure Control and both are enabled, there is
not a control valve for each feature. Rather, there is
one common valve that is either performing Hot Water
Control for Heat Recovery or it is performing Head
Pressure Control. It will not be performing control for
both features at the same time. Normally, it will be
performing Hot Water Control unless certain operat-
ing conditions cause it to switch over to Head Pressure
Control. When performing Hot Water Control, “HOT
WATER” is displayed. When performing Head Pressure
Control, “HEAD PRESSURE” is displayed. There are
also conditions under which it is not controlling either
one, in which case “INACTIVE” is displayed. Which
feature will be controlling the valve at any given time
and when it is inactive is determined by operating con-
ditions as shown in the flow chart in Heat Recovery
Section 24 in Service Manual 160.54-M1.
Control Valve output
Displays the position command being sent to the control
valve. If Hot water control is enabled and there is flow
in the Heating Condenser, the valve is performing Heat
Recovery Control. Otherwise, if Head Pressure Control
is enabled, it is performing Head Pressure Control.
Displayed over the range of 0.0% to 100%. The actual
value of the output signal for a given error depends on
whether the PID OUTPUT setpoint is set to DIRECT or
REVERSE. If set to DIRECT, the 0.0% output will be at
minimum; the 100% output will be at maximum. If set
to REVERSE, the 0.0% output will be at maximum; the
100% output will be at minimum. Only appears when
Hot Water Control is enabled or Head Pressure Control
is enabled.
Control Valve Control Mode
Displays whether the Control valve is in automatic or
manual control. Only appears when Hot Water Control
is enabled or Head Pressure Control is enabled.
prograMMaBLe
hot Water Control
(Enabled or Disabled; default Disabled) Allows the
Service Technician to enable and disable the Hot Water
Control for the Heat Recovery feature. When enabled,
Control Valve will control the Return Condenser Liquid
Temperature to achieve the Hot Water Setpoint (see
below).
hot Water setpoint
(65.0 to 125ºF; default 95ºF) Sets the temperature to
which the Control Valve will control the Leaving Heat-
ing Condenser Liquid Temperature. Only appears when
Hot Water Control is enabled (see above).
head pressure setpoint
(15.0 to 60 PSID; default 23.0 PSID)Sets the pressure
differential to which the Control Valve will control the
Head Pressure. When both Hot Water Control and Head
Pressure Control are enabled, the Control Valve will
normally be performing Heat Recovery (controlling to
the Hot Water Setpoint). However, it will switch over
to Head Pressure Control when certain operating condi-
tions are met as shown in the flow chart in Heat Recovery
Section 24 in Service Manual 160.54-M1. Only appears
when Head Pressure Control is enabled.