Pump not coming to pressure in cold weather

[MDrost1]

The original pump in question draws from a warm water rinse tank. It is fine when it there is no cycling weep.

The HP hose runs from the pump down to about the ground, and then heads laterally about 7 ft., then heads up into the trough. Creating a "U" from the pump connection to the trough. Is it possible when the cycle weep is on, lower volume of water, that the pump water actually drains overnight and settles in the bottom of this "U" thus the cavitation? I hope this makes sense, getting late over here.

 

[MDrost1]

Follow up:

So, after digging into the pump stand wiring and patiently assessing the situation, I discovered that two of my 5 bays had the cold water solenoid disconnected. Courtesy of the previous owners. Spent sometime installing all new cold water solenoids, powering them correctly, and whaddayaknow...all works great.

Thanks for the help!

PS - My wash had and probably still has some funky little issues that the previous owners passed on to me....

 

[MEP001]

I just worked on a wash yesterday where the wires to the spot-free and the wax were swapped, evidently when it was wired in almost 20 years ago, and no one in that time bothered to look into why there was no wax on that bay. The things you find...