# Wired Carbon Monoxide Detector replacement questions



## Mr Chips (Mar 23, 2008)

I have 3 Sentrol 240e carbon monoxide detectors in my home ( one on each floor)









They were professionally installed about 5-6 years ago, and have reached the end of their life, and need to be replaced. Since these are no longer available I am replacing these DIY with the new GE version, the CO-250









My existing one's are each individually "home run wired" back to the panel, and there is a single resistor wired in to all of them at there. The wiring diagram for the new one shows a resistor put in at the actual detector rather than at the panel.

My question is, does it matter if resistor is at panel or at the actual detector? I would think it wouldn't, but i saw on one forum where someone was saying at the panel is a bad idea. can any one shed a little light on this. thanks


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## Wildie (Jul 23, 2008)

Mr Chips said:


> I have 3 Sentrol 240e carbon monoxide detectors in my home ( one on each floor)
> 
> 
> 
> ...


 I'm unfamiliar with wired CO detectors, but I would suggest that you would follow the install directions explicitly.
Then, should a problem arise, the manufacturer cannot refuse a claim because it was wired wrong.


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## Mr Chips (Mar 23, 2008)

Wildie said:


> I'm unfamiliar with wired CO detectors, but I would suggest that you would follow the install directions explicitly.
> Then, should a problem arise, the manufacturer cannot refuse a claim because it was wired wrong.


I'm not worried about warranty as much as safety. that being said, the less i have to mess with stuff in the panel means the less chance i have to mess anything up. thanks for the response


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## Wildie (Jul 23, 2008)

Mr Chips said:


> I'm not worried about warranty as much as safety. that being said, the less i have to mess with stuff in the panel means the less chance i have to mess anything up. thanks for the response


 I was thinking of safety also! Didn't want to come right out and say it, but if you and your family succumed due to CO, someone could be held accountable.


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## Ron6519 (Mar 28, 2007)

Mr Chips said:


> I have 3 Sentrol 240e carbon monoxide detectors in my home ( one on each floor)
> 
> 
> 
> ...


Are these part of your home alarm system?
Ron


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## iminaquagmire (Jul 10, 2010)

I assume these have a resistor being a part of a low volt fire alarm system. I've never personally dealt with them, however I would suggest you look for CO detectors with LCD displays. It makes it much easier to trouble shoot them. Counting beeps when time is important is not something I particularly care for. I am glad to see you are proactive in keeping up with replacement. Most people never think about them until they go off.


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## Mr Chips (Mar 23, 2008)

Wildie said:


> I was thinking of safety also! Didn't want to come right out and say it, but if you and your family succumed due to CO, someone could be held accountable.


LOL, if I'm dead whose fault it was will be the least of my concerns!!



Ron6519 said:


> Are these part of your home alarm system?
> Ron


Yes, when i had the system put in I had them put in three, one on each floor



iminaquagmire said:


> . It makes it much easier to trouble shoot them. Counting beeps when time is important is not something I particularly care for. I am glad to see you are proactive in keeping up with replacement. Most people never think about them until they go off.


Not much to think about or trouble shoot, when they beep and the light is red instead of green you open some windows and get outta dodge!!


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## fireguy (May 3, 2007)

iminaquagmire said:


> I assume these have a resistor being a part of a low volt fire alarm system. I've never personally dealt with them, however I would suggest you look for CO detectors with LCD displays. It makes it much easier to trouble shoot them. Counting beeps when time is important is not something I particularly care for. I am glad to see you are proactive in keeping up with replacement. Most people never think about them until they go off.


 
Did the new detectors come with resistors? What is the voltage of the new detctors and the existing panel? Are the detectors listed for use with a panel, if so, are they listed for use with that panel? This assumes there is a panel.


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## Mr Chips (Mar 23, 2008)

fireguy said:


> Did the new detectors come with resistors? What is the voltage of the new detctors and the existing panel? Are the detectors listed for use with a panel, if so, are they listed for use with that panel? This assumes there is a panel.


New detectors were ordered but have yet to arrive ( hopefully today). When my system was installed, these detectors did not exist. My original detectors were Sentrol 240 and GE bought Sentrol and disconed the 240 and came out with the 250 ( the ones I ordered) as it's replacement. The specs on both are nearly identical and my guess is GE made the change in appearance and model # because of a recall they had on these back in 2002


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## aaronbrace (Mar 27, 2011)

*Resistors are important*

You definitely want to use the resistor and it should be installed at the CO detector. The resistor configuration is there so that the alarm panel can "supervise" the CO detector. This is required for any life-safety devices like smoke and CO detectors. Your alarm panel may need to be reprogrammed for this zone for this to work. On a DSC panel this zone should be set as "24-Hour Fire".

When wired properly, it works like this:

Normal Operating Condition: Panel sees 5.6KOhm. Things are good.
When in alarm: NO contact closes and shorts out the resistor. Panel sees 0 Ohms. This indicates that you have a CO alarm
Fault/Trouble: Panel sees an open circuit (billions of Ohms). This indicates trouble.

So, if the wire gets cut going to your CO detector, or if the CO detector senses the sensor is going bad, it will open the circuit. Your panel will read this and show a malfunction light on the keypad to tell you that the zone has a problem without rolling fire trucks.

Long story short, it is much slicker and safer wiring it properly with the resistor.

---Aaron


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## Wildie (Jul 23, 2008)

aaronbrace said:


> You definitely want to use the resistor and it should be installed at the CO detector. The resistor configuration is there so that the alarm panel can "supervise" the CO detector. This is required for any life-safety devices like smoke and CO detectors. Your alarm panel may need to be reprogrammed for this zone for this to work. On a DSC panel this zone should be set as "24-Hour Fire".
> 
> When wired properly, it works like this:
> 
> ...


 I agree with you totally Aaron! :thumbsup: In days of yore, before I retired I serviced fire alarm systems and end of line resistors are commonly used.
I was reluctant to say, in regards to CO detectors as I retired before these came into use.


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