Merlin MJ3800 Installation And Operating Instructions Manual page 9

INSTALLATION STEP 4
Attach the Cable Tension Monitor (Required)
Your MJ3800 is supplied with a cable tension monitor.
This safety device is supplied to monitor the cable for
ANY slack that may occur and will reverse the door
when excessive slack is detected, eliminating service
calls.
The cable tension monitor MUST be connected and
properly installed before the door opener will move in
the down direction.
NOTE: The cable tension monitor is shipped for left
side installation. It is preferred that the cable tension
monitor be installed on the same side of the door as
the opener.
If required, it can be mounted on the opposite side of
door. Remove the snap-ring holding the roller in place
and reassemble it on the opposite side of the cable
tension monitor.
1.Position the cable tension monitor as shown
(Figures 1 and 2). The cable tension monitor
should be located as close to the drum as
possible.
NOTE: There must be no obstructions in the
installation area that prevent the cable tension
monitor or the cable itself from closing completely
when slack is detected.
2.Make sure cable tension monitor is located over
a wood support member.
NOTE: If the cable tension monitor can not be
mounted into wood with the lag screws provided, it
can be mounted into 25mm (1") or greater pasterboard
using the wall anchors (2) and the #8 hex head screws
(2) provided in the hardware bag.
3.Mark and drill 5mm (3/16") pilot holes for screws
(pilot holes are not required for anchors).
4.Attach the cable tension monitor to the wall
using the hardware provided. Make sure that the
roller is on top of the cable.
5.Run bell wire to opener. Use insulated staples to
secure wire in several places.
6.Connect bell wire to the green quick-connect
terminals (polarity is not important) (Figure 3).
NOTE: Cable must have tension through entire travel.
Make sure there is no slack in cable on opposite side
of the door during normal operation. If this condition
exists, adjust cables as required.
Figure 1
Figure 2
Figure 3
Staples
9
Opener
Torsion Bar
Drum
Cable
2"-6"
(5 cm-
Cable
15 cm)
Tension
Monitor
1/8"-1/4"
Cable Tension
(3 mm-6 mm)
Monitor Roller
With Door Closed
Preferred Orientation
Drum
Cable
3/4" Min.
(18 mm Min.)
WHT/GRN
WHT/GRN
Wall
Cable Tension
Monitor
Strip wire (11mm)
To insert or release wire,
push in tab with
screwdriver tip