System Sensor 2551 and 2551T Plug-in Intelligent - Manual (Page 3)

D500-04-00 3 I56-292-05
NOTE: If the sensor’s sensitivity limits or the MOD400R
limits do not appear on the back of the sensor, the
MOD400R is not suitable for field sensitivity test-
ing of that unit.
C. Smoke Entry Test per NFPA 72
The field test tool is the Gemini Model 501 aerosol gener-
ator. Set the generator to represent 4%/ft to 5%/ft ob-
scuration as described in the Gemini 501 manual. Using
the bowl shaped applicator, apply aerosol until unit
alarms. If the Gemini unit is not available, a punk, cot-
ton wick, or cigarette are acceptable means of generating
smoke to test all System Sensor ionization and photo-
electronic sensors.
NOTE: This test only verifies proper operation of the sen-
sor and is not used to test sensitivity.
D. Direct Heat Method (Hair dryer of 1000-1500 watts)
Direct the heat toward the thermal collector. Hold the
heat source about 12 inches from the detector in order to
avoid damage to the plastic. The detector will reset only
after the collector has had sufficient time to cool and the
power source has been momentarily interrupted.
After testing, detectors must be reset from the control
panel. Notify the proper authorities that the system is back
on line.
Sensors that fail these tests should be cleaned as described
under CLEANING and retested. If the sensors still fail these
tests they should be returned for repair.
CAUTION
Dust cover is not a substitute for removing sensor during
new construction or heavy remodeling. Cover only helps
limit dust entry.
Cleaning the Sensor
NOTE: Before cleaning, notify the proper authorities that
the smoke sensor system is undergoing mainte-
nance and will temporarily be out of service. Dis-
able the loop or system undergoing maintenance to
prevent unwanted alarms.
It is recommended that the sensor be removed from its
mounting base to facilitate easier cleaning (see Figure 3).
The sensor is cleaned as follows:
1. Remove the sensor cover by placing a small bladed
screwdriver in the side slot of the sensor cover, twisting
it slightly until the cover can be turned counterclockwise
for removal.
2. Vacuum the screen carefully without removing it. If fur-
ther cleaning is required continue with Step 3, otherwise
skip to Step 6.
3. Remove the screen by pulling it straight out. Vacuum the
inside.
4. Clean the vaned chamber piece by vacuuming or blow-
ing out dust and particles.
5. To replace the screen, orient it so that the arrow on top
aligns with the field test slot on the base of the detector.
Carefully push the screen onto the base making sure it
fits tightly to the chamber.
6. Replace the cover by gently rotating it clockwise until it
locks in place.
A78-1941-01
REMOVABLE COVER
REMOVABLE SCREEN
P/N RS24 (W/O THERMAL)
RS24T (W/THERMAL
TEST SLOT
Figure 3: