How/where to mount heat sensors in attic?

[JimS]

Planning to add some heat sensors in the attic - one for attic and one for house (although the garage ceiling is the fire "wall" and the attics are open to each other I figured one at each end would be good).  Should I try to mount them near the top?  Just use a nail on box to the side of a truss member and mount the sensor to that?  Am I right that they be mounted at any angle?  Or do they need to be horizontal?
 
My plan is to add them to the end of a 4 wire smoke zone.  Extend all 4 wires and put the power supervision relay at the end device (an attic temp sensor).  Seems like the only way to get full supervision of power and zone wires to all the devices but I may be missing something...

 

[Del91574]

You can put the EOL relay at the smoke provided you run enough conductors to bring the heat loop back to that detector/relay rather than pulling a powered circuit through to them.
 
Typically they are installed parallel to framing. In the case of a peaked roof, they are in the triangle that is defined as within 3' of the ridge.
 
30' distance is usually the max unless they are spot detection.