Alternative to a flowswitch....
Alternative to a flowswitch....
(OP)
...I have a unique situation in an apartment building that my company sprinkled. Every so often the flow switch paddle "trips" sending a false signal to the alarm bell. After discovering that this happened without a leak, a blowout, or a sprinkler head going off we elected to replace the flow switch. Several weeks later, the same thing happened-we then replaced the flow switch again and once again the same thing happened. We then came to the deduction that there were pockets of air bubbles in the system-most likely at the end of the sprinkler line near the last head on the line. We figured that once the domestic pump kicked on at night the surge of water pressure pushed the air bubble to such an extent that the flow switch "thought" that a head had gone off. We noticed that if we bled the last heads on each line just slightly that the air bubbles would escape and dissipate. The problem is that whenever this system is tested and serviced the same thing will continue happening. I suggested that perhaps we eliminate the traditional paddle flow switch for an alarm check but due to cost that may not be equitable. Another idea I possibly had would be to see if there were microscopic pin-hole leaks in the piping that were too small for water to escape as anything other than condensation and that perhaps air is seeping in. Another idea would be to replace the head-the disc or the cap could have a small pin hole. A small enough hole would not necessary make one notice since the water leakage would be akin to condensation. Are there any other solutions out there or would we just have to keep going back to this one particular building and continuing to bleed off the last heads on each line ? Any help would be most beneficial.





RE: Alternative to a flowswitch....
RE: Alternative to a flowswitch....
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Fire Sprinklers Save Firefighters' Lives Too!
RE: Alternative to a flowswitch....
Good luck!
RE: Alternative to a flowswitch....
The time delay did the trick.
Good on ya,
Goober Dave
RE: Alternative to a flowswitch....
RE: Alternative to a flowswitch....
also is the sprinkler underground main a seperate line/ tap from the domestic, or is it tapped off the domestic at the building???
what is the staic pressure also??
RE: Alternative to a flowswitch....
RE: Alternative to a flowswitch....
Response to NightME: The provision of one retard chamber and a pressure switch in lieu of the flow switch would most definitely lead to more frequent false fire alarms. The time delay associated with a flow switch is much longer and also easier to control/adjust.
RE: Alternative to a flowswitch....
RE: Alternative to a flowswitch....
I´ve used air vent valves on private mains, but I´m not sure if there is a NFPA 13 issue about a venting device on the sprinkler downstream the sprinkler control valve.