Can Anyone identify this?

submitted by:
Michael Thomas
Paragon Home Inspection, LLC

If I'm not mistaken, that is called a "rate of rise" used in fire alarms. Senses when the air temp rises too fast and trips the alarm. Or burns a element on the inside and trips. I've seen them but never actually taken them apart to see what makes em tick.
Jerry

AFAIK, they were used a lot in commercial installations in the late 50's and early 60's.

I have seen them and I have installed them They are "Rate Of Rise" heat detectors. They could also be "Fixed Temp" heat detectors. You would use a fixed temp in the attic, because a Rate of rise, might go off on a hot summer day. They replaced another type of fire detectors. ( I wish I had pictures of them.) The older types of fire alarms relied on copper piping filled with air. The "Heat Sensor" was a bigger copper tube connected to the smaller piping. This whole piping system was pressurized. If there was a fire, the pressure would build up in the pipes and set off the fire alarm system. They were very difficult to trouble shoot if you got a leak. You would have to walk around the whole building with soapy bubble water. You would spray the bubble water onto the copper pipes and look for leaks.

AFAIK-- Excuse my ignorance. But what the heck does this mean? I see it every where and feel 'so outa the loop'.

"Rate of rise"- heat detectors need to see a certain rise in temp with in a few seconds. Say 20 deg in 20 sec.
"Fixed temp"- heats need to reach the desired temp before activating.
And the new ones- 1980 and beyond= are combo if so desired.

HID- (wording escapes me now- sorry)-"The older types of fire alarms relied on copper piping filled with air. The "Heat Sensor" was a bigger copper tube connected to the smaller piping. This whole piping system was pressurized. If there was a fire, the pressure would build up in the pipes and set off the fire alarm system. They were very difficult to trouble shoot if you got a leak. You would have to walk around the whole building with soapy bubble water. You would spray the bubble water onto the copper pipes and look for leaks."

Harold, your correct. these are very good. But. only filled with Ambient air. when heated the air pressure rises closing the ckt. Or pessurizing the solonoid.

Still VERY common in special hazard fire Suppression applications. Where no electrical current would be acceptable..
Flamable storage etc.

AFAIK = As Far As I Know. Don't feel badly. I'm still scratching my head over IIRC.

If I Remember Correctly...

You know, I thought of that, after I posted. That's the story of my life, great ideas that come too late. Thanks for your confirmation.

How's Malden, by the way? I lived there, at that big complex on the Hill, Kennedy Drive, back in 1999.

The device is known as a 'Fyrindex' thermostat and was made in both fixed temperature and rate-of-rise versions. At some point in the life of the product is was made by the Kidde Corporation. They are no longer produced.

Those were common in college dorms, back in the mid 1970s. In the halls and sometimes in each room. Some also had scorch marks from idiot prankster students holding cigarette lighters near them, seeing if they could be set off...