9
installation
&
operation
manual
|
oxm
/
ogm
heating
system
3.7
HIGH-LIMIT TCR
(TEMPERATURE CONTROL
RELAY)
The high-limit TCR (TCR2) is a protection device to
prevent oil overheating. The high-limit TCR uses a
resistance temperature device (RTD) located near the
tank outlet. The default setting for the high-limit TCR is
194 °F (90 °C) at 0% hysteresis and should always be at
least 18 °F (10 °C) higher than the control TCR set point.
The high-limit TCR hysteresis is not used in the high-limit
control.
See Fig. 7
.
3.8
CONTROL TCR
(TEMPERATURE CONTROL
RELAY)
The control TCR (TCR1) is used to control the
temperature of the oil. The control TCR uses a resistance
temperature device (RTD) to sense the temperature
of the fluid as it enters the heater and will deactivate
the element when the set temperature is reached. The
standard setting for the control temperature relay (TCR1)
set point is 104 °F (40 °C) at 10% hysteresis.
See Fig. 7
.
Figure 7. OXM/OGM motor protection switch (above), showing
stop/off
(A)
and reset/on
(B)
buttons. To reset the MPS, the heating
system must be switched off and either the
reset
button or the
MPS reset/on button must be pressed.
OXM/OGM control TCR and high-limit TCR (left). The standard
setting for TCR1 control dial
(C)
is 104 °F (40 °C).
A
B
C
CN ORNL
HIGH
LIMIO
A
B
C
CN ORNL
HIGH
LIMIO
