Engine room fire alarm

[Docrockit]

Help needed. Our 2006 54 Convertible woke us up at 3 am this morning. Outside alarm going off. Went right to the Hatteras display which indicated Engine Rm Fire. And Extinguisher has discharged. Silenced the alarm (but cannot reset alarm message). There was no fire in the engine room. I did have a ceramic space heater which was running normally when I went and checked in it. But the engine room was not warm. On fact, it was cold. But not freezing. There was no evidence that anything had happened. The only thing was that it was the coldest night of the year so far. Outside temp got down to 20 degrees. Picture of the FM-200 canister gauge is attached. Did cold temperature activate this? What made it think it was on fire? Any way to reset the Hatteras display message?

[Captain Ralph]

It may not have discharged, but from the cold, contracted a lil.

Usually a box on the forward / port engine room bulkhead, pull to bypass switch for the CO2 systems. Sometimes used for later gas systems.
Yours looks like halon or later similar gas.
Later control boxes or panels have a red/green light and bypass switch with it.
Usually around the lower helm.

If this is a recent purchase, your survey should have the bypass location noted.
Hope it was tested for the survey.

If the fire equipment was inspected, the bypass should be noted on the report.

Worse come to worse, pull out your prints, locate the alarm panel fuse and pull it.
It is in one of the DCv boxes in the ERs.

[Pascal]

A few years back I used to have a big FM200 in a 70 footer that used to be just over the red overchatged line when the ER was real hot after a long run. Once cooled it would come back to the middle of the green. One time I was boarded the the USCG pointed it out but didn’t write me up since we had more than enough handhelds

I wouldn’t be surprised if this is just the opposite effect. As Ralph said there should be an override to shut off the alarm

[Docrockit]

Problem solved (I think)! Thanks Captain Ralph and Pascal. I got the ER heated up and the contents of the canister seem to have re-expanded. A picture of the gauge needle attached. Then, I pulled the fuse located in the DC panel box located on the portside forward bulkhead. The message on the Hatteras LED display disappeared. Still dont quite understand why the boat thought it was on fire just because the contents in the canister looked low?? But relieved none the less. Thanks again guys! Your expertise is greatly appreciated!

[Pascal]

Yes if the bottle pressure is too low, it will trip the alarm