Slow fill times for 444c dual pack

I just finished installing a dual pack of 444c on a five gallon 200 psi tank. Viair’s website: http://www.viaircorp.com/OnRoad/dual444c.html says it should take 5 minutes and 30 seconds to fill from empty. I timed mine and it took a little over ten minutes, I was wondering if any of you might have an idea as to why mine are so slow.

sounds to me like on of your checkvalves is stuck or put on wrong…

Drain your tank first, take the lead hoses fittings off the tank and turn on compressors see if air is coming out of both or just one…

Thank you for the suggestion, I just went and tried that and both of them are putting out air. Any other ideas or things I should check?

maybe your not getting enough voltage…? what size power wire are you running?

I measured 12.6v at the compressors with a dmm. Also I am running an 8 wire from the battery to each compressor.

Do you have filters on both compressors? check the inlet on both to make sure the air is pulling without a cap in there or something…

take a picture of your setup and post it so we can help more…

Narrow it down to which one. Disconnect power to one at a time & do a full fill with the other one. (or just time it up to 150psi) Then switch.

One of my ground wires was apparently too small, it overheated and burned a hole in my air line, I’m not sure when this happened so I cant say 100% that it was the problem, or if its a new one. I ordered the new line and I’ll know for sure when it gets here. Thank you all very much for your help, and I’ll post back to let you know if that was the problem, or if the diagnosis continues.