Well I finally took off the check valve like Mep1 told me to and I am going to see what the ramifications are going to be. Greg told me that the system is supposed to have a check valve and for the air to blow down (for cold weather). The problem could be that the system will allow air to travel into the holding tank? Who knows but I bet this is going to fix my problem.
(The problem is the pre-soak occasionally does not work out on the gantry. The outgoing hose builds up pressure which does not allow the pump to pump out liquid.)
That’s such a typical, overcomplicated way for them to do something. That means you actually have three check valves; one to stop the high-pressure from the machine, one to stop the air from backing up into the tank, and one to stop the presoak from backing up into the air. If you have issues with the air in the presoak, I would recommend relocating the check valve for the air blowdown to its own T so it will only blow down the line to the bay and not the presoak system. You’ll have fewer check valves, and if one fails you’ll get water backing up with no harm to the equipment and you won’t be shut down.
Factory install is just one check valve in the system right below the pressure gauge on PS1. Someone has added or moved check valves on your system if you have one on your pump. You need to see if the one is still on your pressure gauga and if so if it is functioning properly. If so, you you have ruled out just about all “plumbing” problems. Check your wiring, especially your common on your presoak solenoid. You have an old unit and corrosion on the connections on the gantry could be playing an issue.