Problem with my Tap-A-Draft?

Just got a TAD and am using it for the first time. I primed and carbed the beer normally. I hooked up the tap and let sit in the fridge overnight. Next day we started drinking it, and all was well at first. But after a couple hours, pressure dropped and I had to add another CO2 cartridge. Later in the day I had to add a third cartridge. Today (3 days after tapping) pressure is down again. That will make four cartridges in as many days. I know the seal to the bottle neck is good because no liquid leaked out when the beer was above the neck. I'm tightening the cartridge holders pretty tight already. Am I doing something wrong??? Could the beer have been under-carbed and now I'm losing CO2 to force carbing???

Just because the liquid doesn't leak out doesn't mean you don't have a leak.

I started using teflon tape on the threads. Seemed to work better.

Going through 3 as fast as you are wouldn't mean it's going into carbing the beer, BTW. It takes a good couple weeks to force carb, just like with a real draft system.

How does the CO2 escape without forcing out liquid? Anyway I'll try teflon tape on the bottle threads when I tap the next one. Thanks for the tip!

If you plug a cartridge in when the bottle's really full or the pressure is already at 15psi, most of it will bleed off through the pressure relief valve. Only replace the cartridge when it quits pouring and only replace one cartridge at a time.

I only replaced a cartridge when the pour got really slow. When I did, I got a big inrush of CO2 into the bottle, so I don't think the bottle pressure was over 15 psi. I'm going to tap a second bottle tonight (with teflon tape on the threads. Hopefully I have better luck this time.

It takes a little time to figure out how often to replace the cartidges to keep the carb level just right and flowing well. It depends upon how fast you drink, temperature, and other factors. I started using just one cartridge, then putting a second in when it slowed down. Usually two-three cartridges per bottle, depending upon how fast it was drunk. This was for already carbed beer, and I used the whole amount of sugar for priming, not the amount they recommend in the instructions.

It gets better with time/practice. Not quite as easy as a full kegging system, but easier than bottling and cheaper than buying a kegerator!

Edit - re-reading your initial post, I thought of one more thing. I think some carbonation comes out of solution when the beer level is low, like at 1/3-1/4 or so. If we weren't drinking it quickly, and it was getting close to needing a new cartridge, it'd be a little flat after several days. Makes sense, as it's not at 15 psi anymore, maybe 4 or 5. But putting in a new cartridge would always make it great in a few days. Some CO2 gets absorbed, some remains for pushing the rest out.