Dry Fire Sprinkler System

They use a special reinforced rubber pressure hose on this system, and after a time, the heat from the compressor hardens the hose at the clamp, and it leaks! I heard the compressor running too often and did some leak checks. The fittings, and the head gasket were leaking. Service came down and changed the hose but said the head cant be resealed. They want to put in a bigger compressor that won't run as often, for over 2G. This one is a 1/3hp General. I haven't called General about it yet. I don't think i have any increased leaks in the system. The issue may only have been that hose, and the leaks while running.

Oh, and when it shuts off, pressure remains in the line, even though there are small fitting leaks. I can pull the pressure release valve 1/2 hour after shutoff and there's pressure in the line. Makes me think that the residual pressure in the line, is holding the check valve open. THATS MY REAL QUESTION HERE! Can line pressure, after shutoff, keep a check valve from closing completely? There is not an unloader on this small unit.Service company says no.

Thanks for any and all help,

Payson.

You didn't call "General" whoever that is, and you came here? The line is supposed to under a light pressure to keep the valve closed. When there is a fire and a head opens it is more than the pressure can overcome and the line pressure takes over. Do not try to solve this by applying more pressure. Get a new sprinkler contractor. You are not allowed to fuck with it.

Why the bad language? Bug out of my post if you can't be civil!
General is the manufacturer of the compressor.
Pressure on the main valve is around 43psi.

All other comments are appreciated.

PG

Flute Maker said:

Why the bad language? Bug out of my post if you can't be civil!
General is the manufacturer of the compressor.
Pressure on the main valve is around 43psi.

All other comments are appreciated.

PG

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Mass people need thicker skin to deal with some other parts of the country. Sprinkler systems have a slew of inspections and regulations. I have several buildings with dry valves. And my landlady also owns and runs a good size mechanical piping company. Get another opinion from another sprinkler company because your insurance may be in question if your good intentions compromise the system.

If I understand the check valve question correctly, wouldn't the pressure be equal on each side of the valve after the compressor shuts off? I can see the valve being faulty, but couldn't see any way that pressure is holding it open?

I also doubt of any other options that would be cheaper than the $2k compressor replacement, and suspect that they probably don't ever rebuild the compressor heads due to liability. Fire sprinklers are just one of those things that is as simple a system as can be, but so heavily regulated that you end up paying $8k for two low skill laborers to install 50' of black pipe with vic fittings... Not really any way around it.

johfoster said:

If I understand the check valve question correctly, wouldn't the pressure be equal on each side of the valve after the compressor shuts off? I can see the valve being faulty, but couldn't see any way that pressure is holding it open?

I also doubt of any other options that would be cheaper than the $2k compressor replacement, and suspect that they probably don't ever rebuild the compressor heads due to liability. Fire sprinklers are just one of those things that is as simple a system as can be, but so heavily regulated that you end up paying $8k for two low skill laborers to install 50' of black pipe with vic fittings... Not really any way around it.

Click to expand...

Reality is a very small compressor with a long charge time to keep the flapper closed. The system needs to trip at a very small pressure drop. And sometimes that drop causes a slam pressure in the sprinkler system where other sprinkler heads blow, or other dry systems in the complex trip.
Several times when my systems were being tested I hooked up my air system to charge the pipes, sprinkler men asked for it. They removed the fittings after and locked the main valves.