I am not even sure if double regulators is the right description so I will describe what I had and what I have now and the difference.
I have a buried propane tank, comes into the house, splits to fireplaces (which we don't use) and to a deck output. It is a 1/2 pipe sticking out with a shutoff. The shutoff is female threaded. I used to have coming off of the shutoff a quick disconnect (from fairview fittings) which then went straight to my grill. No regulator at all because the propane people (who own and installed the big tank) told me I didn't need one because it was regulated at the meter. It worked well. It was at times hard to get the grill temperature down but I bet if I turned off some of the burners I could have accomplished that, not that I needed it.
Fast forward a year later, I get a smoker. It wasn't going to be easy for me to hook it the same way so I went a different direction. Replaced the quick-disconnect which was connected to the shutoff valve with a QCC1 male, then converted back my grill to the way it used to be.
So now I have a QCC1 (same thing you get out of a 20 lb cylinder) coming out of my house. The grill and the smoker both have their normal hoses with a QCC1 Female connector coming right out of a regulator.
My problem is that the smoker struggled to get past 200 degrees (which I blamed on the doors because I had heard they might have problems sealing), but then I tried using my grill tonight for the first time and it also struggled. It couldn't keep all four burners on, and with two it never got past 250.
Is my problem the double regulators, the one at the meter and the other at the individual devices?
I am going to buy some of that compound that I can use instead of teflon tomorrow and remove it all and reinstall it just to make sure I didn't get teflon obstructing the flow. Any other ideas?