Fuses; Leds; Earth Grounding Wire; Red Led Indications - Regency 4720 Installation Manual

Regency ® Model 4720 Control/Communicator Installation Manual (P/N 150476, Rev. A)

Fuses

3.3.2
PC board revisions prior to Revision L still use Revisions A-K for overcurrent protection.
• F1 is a 2.5-A Fast Blow Fuse that provides overcurrent protection for an AC Siren Speaker
connected to Terminal 4 of the Model 4720.
• F2 is a 1.5-A Fast Blow Fuse that provides overcurrent protection for touchpads and any
accessories connected to Terminal 5 of the Model 4720.
• F3 is a 1.5-A Fast Blow Fuse that provides overcurrent protection for expansion modules and
smoke detectors connected to Terminal 10 of the Model 4720.
• F4 is a 4-A Fast Blow Fuse that provides overcurrent protection to the battery.
To avoid fire hazards, the Model 4720 is designed with backup
nonreplaceable fuses in series with the replaceable fuses
(power-limited design). It is VERY IMPORTANT that you
replace fuses with FAST-BLOW type fuses with the SAME
AMP rating as the old fuse. If you replace a fuse with a higher-
rated or slow-blow type fuse, the nonreplaceable fuse will
blow, and the panel will have to be returned to the factory for
repair.
NEVER put a jumper across any fuse. A jumper across a
replaceable fuse will cause one of the nonreplaceable fuses to
blow. A jumper across a nonreplaceable fuse could cause a
fire.
When a replaceable fuse blows, find the cause of the excess
current by (1) using an ohmmeter and (2) replacing the fuse,
then connecting up one device at a time to see which device
causes the fuse to blow. Repair the short, then replace the
fuse with the same type and rating. Keep spare fuses in your
tool kit.

LEDs

3.4
The red LEDs are normally OFF, and come ON under the following conditions:
LED #
1 Top right corner
2 Lower right side
3 Lower right side
4 Middle, right side
5 Top, center

Earth Grounding Wire

3.5
The magnetic field of a nearby lightning strike can induce damaging currents in the wiring of an alarm
system. Even distant strikes can affect the panel through the AC or telephone wiring. The 4720 has built-in
transient protection devices, but in order to work, they must be able to shunt the transient currents to earth
ground. The green Earth Grounding Wire (included) must have one end installed under one of the four (4)
mounting screws of the Model 4720 printed circuit board. The other end must be connected to a good earth
ground. If this is not available via the ground wire of the building's 3-conductor AC wiring, then a separate
heavy gauge wire should be run to a metal cold water pipe or grounding stake. This wire should be run as
short as possible, and sharp bends should be avoided.
Table 3.4a:
Location on PC Board
CAUTION:

Red LED Indications

Condition(s) Causing Red LED to Light
Terminal 4 (AC siren speaker) overcurrent.
Terminal 5 (touchpads and accessories) over-
current (higher than 1.1 A)
XBUS overcurrent (higher than 1.1 A).
Battery wired backwards.
Terminal 10 (smoke detector) overcurrent.
11
Revised 10/98