You still have an air compressor because the nitrogen generator is a slow pump and you need to make 30 minutes. If you didn't plan on an AMD you need one with nitrogen because it fills a storage tank to anywhere between 60-80 PSI depending on mfgr. and model. The nitrogen kit comes with a purge valve that bleeds constantly at an adjustable very slow rate. Once you reset and fill with air, you close the valve from the compressor and open the valve from the nitrogen tank. The purge valve will bleed off a constant amount of air while the tank makes up. The purge valve is usually at the end or top, like at the EOL and just vents to atmosphere. You also get a purity sensor, either handheld or piped/wired to read concentration (97-99%). The 30x80 I2 group residence I did last summer which had a 2-1/2" low dif valve and main, about 50 heads, took 10 days to go from 79% to 99% from the purge valve. As concentration increases, moisture decreases to zero. My system cost 9K and took a day for the piping for 2 fat guys, I used copper. Oh- There's a shutoff on the purge valve you close before trip testing. NO change due to nitrogen that I know of but a good reason to submit. TD
Segway from the other conversation. Is there anything that gets me back to a C-factor of 120 for a dry system if I use nitrogen instead of air? What happens if I don't maintain the nitrogen part of the generator? Does air get pumped in or does it stop pumping altogether and I deal with the low air alarm eventually? Ballpark what is upcharge for nitrogen vs. air? I've heard mid $teens. If so makes me wonder who's really willing to pay. Just a few I suppose. As EOR I don't want to be throwing around $$$ just because it's a good idea. For example, when the generator costs more than the building may want to stick with a regular compressor in an exaggerated case. Chris Cahill, PE* _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
