Dewalt Roofing Nailer - 2 Nails?

I bought a factory reconditioned Dewalt Coil Roofing Nailer off of eBay and now that I'm starting to use it, I find that it sometimes (fairly often) spits out two nails at a time. I've tried switching the trigger from the bump to the gray one and I've tried reducing the PSI on the compressor, but I don't think either has done any good.

Does anyone have any suggestions?

BTW: Right now, I'm using Stanley-Bostich 7/8" roofing nails because I'm just doing the felt. I haven't yet tried the 1 1/4" nails for the shingles, so I don't know if that'll make any difference.

Thanks in Advance.

 

Welcome to the forums. The 7/8" nails may give a little problem with a double hit. My Bostitch does it occasionally on shorter ones. The longer ones don't do it that much, but I'm not sure if it is the length of the nail or not.

 

Thanks.

I had wondered if the smaller nails may have been part of the problem and there's always the idea that I'm shooting through little metal disks, but I also had to wonder if I was missing some simple fix because not a lot of info was coming up on the subject, via a search.

Thanks again and I guess that I'll just have to keep a regular hammer around, while I do the rest of the felt.

 

Yeah, I don't like shooting nails through metal. Plastic cap nails and a hammer make it easy to do the felt, then go for it on the shingles with the Dewalt.