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Replacing 2-wire Smoke and Heat sensors for ELK M1gold


Active Member

So, a couple of months ago, I got a false Fire trouble call from the Alarm company...

Went and cleaned the sensor and disabled the thing until I could fix the problem (i was Stück out of the country due to Covid).

Now back, I removed the smoke sensor and noticed that there are are more sensors in the loop. I traded the wires to heat sensors above my two flash water heaters.

The tech at Alarm Relays says anything beyond 10 years of age is due for replacement.

The 2W-B is straightforward available on Amazon (expensive).

However, I'm having a hard time locating the heat sensor W15-Y04F (Chemetronics).

Can anyone recommend a 2-wire solution for heat and smoke sensors?



Senior Member
For a 2-wire smoke zone, you need to choose a smoke detector that is certified for use with your alarm panel.  What brand/model of alarm panel do you have?  Is your current smoke detector a 2W-B? 
Heat detectors are pretty straight forward - they basically create a short across the zone loop.  I can't seem to find any specs on the Chemtronics model that you have. You'll need to choose from a detector that trips at either 135°F or 194°F, and whether you also want rate of rise detection or just temperature limit detection.  
The System Sensor 5600 series has a variety of heat detector models to choose from.


Active Member
Thanks RAL,

Yes, the 2W-B is what I currently have.

And on further examination, it seems like that was a date code, not a model number on the Chemtronics... It's 135F

I located both and ordered them. The 2W-B and the 5601P. Way cheaper from JEM security than Amazon, even paying for shipping.

Hope to be up and running soon...