I have a Ultra Jet blower and a few days ago, it was creating air bubbles no problem. I turn the blower on now and I can hear the blower but no air is coming out of any small holes... So I removed the blower to check what was wrong : It's a 7 amp blower and when it's off the piping, I get a constant 6,5 amp wich is ok. When I put it back in it blows thru the piping and starts at 6 and drops to 4.0, 3.8, 3,7, ... and then stops. Looks like my piping is blocked ???? Since I can't see the piping due to urethane isolation, I have no clue how it's made and where could be my check valve ?

Is there any trick to fix this ?

Any help is appreciated...
Thanks!

the first thing to check is to make sure you don't have any air control knobs, if you have knobs that you can turn to change the amount of air being allowed into the spa and the knobs are closed then you will not get any air flow through the injectors. Otherwise the best thing you can do is start digging through the insulation to find and replace your check valve, it should be located fairly close to the blower before the plumbing splits so you may not have to dig far.