Johnson Controls MR4PMUHV User Manual

MR4PMUHV Electronic Temperature/Defrost Control with Relay Pack Product/Technical Bulletin 7
Programming the Control
Use this section to program the control module. After
programming, the control module retains its
programmed settings, even in the event of a power
failure or power-down.
Using the Control Module
During normal operation, the display shows the main
sensor temperature. See Figure 2.
 Press Up or Down repeatedly to scroll through the
main sensor temperature, evaporator sensor
temperature and the binary input status.
 Press Enter to display the Setpoint.
After 15 seconds of inactivity, the display returns to
main sensor temperature.
Unlocking or Locking Access to Programming
1. In sequence, press and hold Enter, Up,
and then Down.
2. Hold these buttons until “- - -” displays.
3. Continue holding until the main sensor
temperature displays (approximately
10 seconds).
Changing the Setpoint
1. Press and hold Enter for
approximately 3 seconds.
2. Release Enter when the new
Setpoint value displays.
3. Press Up or Down to display the
new Setpoint value.
4. Press Enter to save the new
setting.
Note: The control ignores changes and reverts to
the previous saved value unless you press Enter.
Changing Other Function Values
1. Press and hold Enter until HY (the code
for Differential) appears (about
10 seconds). See Table 3.
2. Press Up or Down until the desired
function appears. See Table 3 and
Control Functions.
3. Press Enter. The function’s existing
value appears.
4. Press Up or Down until the desired
setting value appears.
5. Press Enter to save the new value.
After 10 seconds of inactivity, the
display returns to normal operation.
Note: The control ignores changes and reverts to
the previous saved value unless you press Enter.
Initiating a Manual Self-Test
IMPORTANT: Disconnect controlled loads before
running the self-test procedure. Reconnect
controlled loads and cycle power to resume normal
operation.
1. In sequence, press and hold Up and
then Down.
2. Hold for 5 seconds.
Initiating a Manual Defrost Cycle
Press and hold Defrost for 3 seconds to
interrupt normal control operation and
initiate a manual defrost cycle.
Note: If the Defrost Evaporator Temperature is
higher than the Defrost Termination Temperature,
the control does not initiate a manual defrost.
Initiating a Manual Deep Freeze Cycle
1. In sequence, press and hold Enter and
Up.
2. Hold both buttons for 5 seconds.
3. The compressor status LED lights and
the compressor output relay contacts
close.

Johnson Controls MR4PMUHV Specifications