Flat beer in keg after over 1 week! Help.

I kegged my pale ale on August 24, purged with CO2 to get rid of the O2 and put in Keezer at 25psi for 48 hours. On August 26 I turned the pressure down to 12 psi (my serving pressure) and let that sit until August 29. I knew it wasn't quite a week but I thought I'd give it a sample. It was flat as all get-out. No head on the beer whatsoever. I turned up the gas to 15 psi until last night, 9/1, and sampled again. Same thing. All I get are those large clear bubbles on top of the beer, still super flat. I turned it up to 25 psi last night and will leave for a few more days. The temp in my keezer is 40 *F. What's going on here? I've never not had a beer carbonate within a week. I sprayed the seal on the corny and the posts to check for leaks but do not detect anything. Incidently, this was the first time I'd used StarSan. Normally I use Iodophore. Loved the StarSan and I'm sure it has nothing to do with this problem. Here is the recipe I brewed: https://www.homebrewtalk.com/f66/cascades-orange-pale-ale-84558/

Please help me get to the bottom of this.

thanks

I'm not sure why you wouldn't have some carbonation. Are you sure it was really connected?

If you connect the gas to the out post it will carb faster because the gas has to float up through the beer. I had my IPA connected like that at 30 psi for two days. Yesterday I tested it and it was fine so I changed posts and left it at serving pressure.

Maybe a stupid question but...Are you sure you are actually getting gas to the keg? When you bleed the pressure off the keg can you hear gas rushing in? Maybe there is some problem with your system between the regulator and the keg. I cant imagine why a beer would not carb otherwise.

Oh yeah, I double checked the connection a couple times over the last few days.

how much headspace in the keg?

well if you pull the tab and get that hiss of escaping gas then you know you have CO2 in your tank and at least some of it is getting to the keg. have you tried changing regulator? i think it unlikely but it may be giving you false readings. just saying its 25psi when its really much lower. in any case having a back up regulator isn't a bad idea in case the main one actually does break.

Another thought: Do you have a primary guage on your regulator? If your tank is very low it may be just equalizing without really pushing any gas in.

The gas in my CO2 tank is getting pretty low, just a tad above the red "order gas" area. Just an update, I turned the gas up to 20 psi for the last 3 days. The head on the beer was no better. I'm taking my tank in today to get filled. After that, I'll get everything dialed back in and see what happens.

Thanks for the help!

the only reliable way to estimate CO2 in the tank is by weight. the regulator gauge is not a reliable indicator of volume until the tank is nearly empty, then it just plummets. My tank, when full, shows just above the red area on the gauge if the tank is kept in the keezer, a bit higher if kept outside of it.
the tank itself should have a tare weight printed on it, without your gauge/regulator setup, weight the tank and subtract the tare weight and you should be able to get pretty close to how many pounds of liquid CO2 you have in the tank.