Yes it would be very easy to cap it off. Literally shut the valve supplying the water.

I do like the idea of a sprinkler system protecting my two 911s

How much water damage would it do if that went off?

The interior is dry walled, books, pinball machines etc . . . If the sprinklers went off there would be $15,000-$20,000 in damage easy.

. . . but my 911s are in there too. Combined those are worth more than $20,000. I’m thinking a soggy garage is better than baked 911s



Grandma and the boy in a pinball tournament

http://forums.pelicanparts.com/uploa...1651714087.jpg

Grandma and her Brother playing
http://forums.pelicanparts.com/uploa...1651714782.jpg

1975 911 3.0
http://forums.pelicanparts.com/uploa...1651714940.jpg

2000 996 2S
http://forums.pelicanparts.com/uploa...1651714988.jpg

Here is a pressure timeline. . .

May 4
8:00 am : System pressure 85 PSI. PRV Pressure at factory setting 85 PSI

3:00 pm : Recorded ambient outside temperature 81.5 deg F

5:00 pm : System pressure 146 PSI

8:20 pm : System pressure 106 PSI

May 5
3:00 am : Recorded outside ambient temperature 54.5 deg F

7:00 am : System pressure 85 PSI; Recorded outside ambient temperature 56 deg F

1:00 pm : System pressure 120 PSI; Recorded outside ambient temperature 77.5 deg F

3:45 pm : System pressure 140 PSI; Recorded outside ambient temperature 79 deg F

8:00 pm : System pressure 110 PSI; Recorded outside ambient temperature 71 deg F

9:00 pm : System pressure 100 PSI; Recorded outside ambient temperature 67 deg F

May 6
8:00 am : System pressure 85 PSI; Recorded outside ambient temperature 62 degrees F


Likely the heat of the garage attic where the pipes are caused the pressure increase.

The trick will be monitor temperature on a very hot day and on a very cold day.

Maybe I need an expansion tank after all. It is likely I never noticed the wide range of temperatures all these years. It makes sense the pressure rises with the heat of the garage attic during the day. I was thinking of putting an attic fan to keep the garage cool. That would keep the pipes in the ceiling 20 degrees cooler during the heat of the day.

UPDATE:

It is pretty obvious high attic temperatures would have an effect on pressure of the fire sprinkler pipes.

Likely the system has been cycling for the past 20 years high and low pressure depending on those attic temperatures.

I installed a thermostat controlled attic fan today and placed a wireless temperature sensor inside the attic. Hopefully the fan will keep the attic cooler and prevent the high 150 PSI I was seeing on the system.

Time will tell.

http://forums.pelicanparts.com/uploa...1652069077.jpg

"Automatic Fire Suppression"
I thought you got yourself a machine gun with a silencer. ;)