Four Wire Smoke Detector question


Active Member
I finally have become brave enough to tackle adding smoke detectors to the M1. I am using a four wire smoke detector from GE.

The instructions included with it show using the end of line supervised power relay. To make sure I know what I am doing I have just installed one detector with the power relay as shown in the diagram.

When I add it to the M1 it shows Fire Trouble and that there is a short. I searched through the forms and was not able to find this problem specifically. I did find one that seemed to indicate that their should be approx 7 ohms in between the NO and Common terminals and I do have that.

Other than that, I am not sure what I should try next.

Any ideas?




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You should have the End Of Line resistor, 2200 ohms at the end the fire zone. If you disconnect the fire zone from the M1 and measure the resistance on the fire zone it should read about 2200 ohms +-10%. Any detector reading 7 ohms across its NO terminals is in alarm.

The smoke power wire should be connected to the SAUX switched auxiliary power terminals. Use keypad menu 2 to reset smoke power for 5 seconds.

Another test is to put the EOL Resistor directly across the M1 input zone. The M1 should indicate normal.

Read the voltage on the fire zone with Keypad menu 8,6,3. It should show between 4 to 9 volts for normal operation.
OK, This may be part of my confusion. I have a "power supervision relay" (A DSC RM-1) that is wired into my last (only at this time) smoke detector. I am confused. Do I need both this relay AND one of the end of line resistors?

The power supervision relay has wires for NO, Common, +, and -, and I have it attached to the corresponding terminals on the smoke detector, so that both the power supervision relay AND cable back to the M1 are attached. I do not have an end of line resistor in right now.

That is what appeared to be the setup in the diagram, although they also show the end of line resistor in line on the common wire in between the smoke detector and the power supervrsion relay common wire.

Do I need to add the end of line resistor also?




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AFAIK, technically you don't NEED it for any number of detectors, but it is a real good idea. Otherwise there is no warning if the detector loses power for whatever reason.

I also have two 4 wire smokes with EOL and resistor. I have the EOL connected properly and the smokes connected properly (according to the directions.) I have a resistor on the common wire of the last smoke. This resistor has three red striped on it and was shipped with my DSC 5010 module. I was told to use that resistor with the smokes.

The LCD pad does not report any trouble with the smokes, but when I test them with smoke the red light will come on -- indicating an alarm -- but the 5010 does not do anything.

The 001 section of the module for zone 3 (where the smokes are located) are set to 08. When the red light is on I can go into 001 and change zone 3 to 01 and then back to 08, and when I do the module starts indicating an alarm.

So, why doesnt my DSC 5010 indicate a smoke problem? It will only do it when I change 08 of 001 to 01 and then back to 08. Is it a wiring problem? A resistor problem?

Thanks for any help!


B Wright