New and interesting information about Wheelock electromechanical horns

About a year or so ago, I compiled more information about Wheelock’s electromechanical horn strobes, specifically after watching videos from certain fire alarm enthusiasts on YouTube (specifically The Blue CFL, Fahrenheit 4051, and Vintage Fire Alarm Guy). And here is what I found out:

  • There was indeed a 4-wire version of the 7001T, and its model number was F34T-24-WS (“F” standing for flush mount). The only known source is a video from Blue CFL.

  • Wheelock actually redesigned the grille in late 1984. I recall seeing photos from Vintage Fire Alarm Guy posted in the Facebook fire alarm enthusiasts group. He got a 7002T in the summer of 2019; the device has a closed grille, black sounder plate, and it is date-stamped “4784”.

  • The 7002T came out the same time as the 7002. In recent years, more of us have been finally realizing that the “T” means there are screw terminals instead of wire leads for power-up. But there’s still the misconception that the terminal models were released around the time the grille was redesigned. However, after having seen two videos from Fahrenheit 4051, I’ve come to realize that was actually not the case. He has two 7002Ts that were made in the late 1970s (one manufactured in 1978 and the other in 1979). It’s just that the 7002T replaced the 7002 shortly after the grille redesign simply because screw terminals are easier to wire up; and that’s really the only reason you usually see the “T” models with the newer grille.

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Neat info, thanks for sharing, though how do you know for certain that Wheelock redesigned the grille in 1984 specifically if you used only one enthusiast’s 7002T for reference? (unless you know if units made from mid-1984 back have open grilles) You also appear to be contradicting yourself with that third point.


I know @DaSamNudge has some more iterations of these horns, such as horns with different textures of the horns’ paint

I know for a fact that units made in mid-1984 did have the open grille. However, this one enthusiast’s 7002T that has a closed grille was made in November of that year. How do I know this? If you closely examine these date stamps, you’ll see that the first two digits are the week while the last two digits are the year. In the case of this particular 7002T, the date stamp reads “4784”. 47 is the 47th week, and that is always in November; and 84 is the year 1984.

So this is my thinking. The grille redesign occured around the end of 1984, like sometime in November.

Oh, okay, though if you stated that from the beginning I might not have had to ask to clarify.

Yeah, 1984-1985 was a transitional period for these alarms.

  • Wheelock switched to textured paint around mid-1984

  • Grille redesigned around November of '84

  • Around late '85, sounder plate was left silver instead of painted black, 7002 discontinued

There seems to be two textured paints, one rougher and one much smoother but not shiny

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There were two coats of paint for Wheelock’s electromechanical horns.

  • Units made from c. 1969 (30 series) and c. 1976 (7000 series) until early 1984 had the smooth coating of paint.

  • From mid-1984 (a few months before the grill redesign) until 1994, the textured paint was applied

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There were actually at least three paint variants.

A smooth one (photo by DaSamNudge)

And at least two rough ones

In the bottom photo, isn’t that a 34 or a 34T below the 7002T?


Top photo is a 32P-24, bottom photo is a 7002T and a 34-24

I looked at the photo of that particular 7002T I mentioned before, and it looks like it was actually manufactured the 49th week of 1984, which is early December.

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The 32P was a rare alarm. And the “P” stands for the extra power that the horn receives compared to a standard 34 horn, and that’s why it is louder than the 34 and 7002.

By the way I’m curious as to when DaSamNudge’s 32P was manufactured. Could it have been before the 7000 series horn strobes?

Do you have a source on that for the P? It could very well be the 32 that is the difference. Remember how long it was until we figured out the T stood for terminal? Until we have solid proof either way, my guess is that it’s pigtail

First thing, I knew right away that the “P” could not stand for pigtail because the more-common 34 and 7002 models have pigtail connectors, and they don’t have “P” in their model numbers. If P stood for pigtails, then the model numbers would’ve be 7002P and 34P; but that was not the case. Second, I remember reading someone’s comment (either on Facebook, Reddit, or YouTube) that the “P” meant higher input power. But then in this link below, I found out that “P” means polarized.

Interestingly enough, Wheelock also manufactured the 32PT and 32PT-WS models. But I’m not sure if 32P/32PT was still made after the grille redesign.

Yeah, after reading the section that mentions the 32P, it seems more likely it means polarized or power than pigtails, but I’m thinking polarized. Think about it, if the P stood for power, why haven’t we seen a 34P or 7002P? My guess is that the 32 was originally a non-polarized horn that took more current, and the 32P was the polarized version.

Interesting thing is that the 32P is louder than either the 34/34T or the 7002/7002T

Probably the 32 rather than the P, given that the 31 is AC, but 32 and 34 are DC. The model numbers are probably related to the current it takes in rather then the P

and what does it mean when a fire alarm notification appliance is polarized (as is the case with the 32P)?

The polarization makes it so that the alarm will only sound when power is applied in the right direction by use of a diode. New systems supervise the NACs by sending a small amount of current in the “wrong” direction, and the diode prevents supervision current from sounding the alarm