I installed a pressure tank during the camping season last year. In the fall I didn’t winterize for the first cold snap but ran electric heaters and the furnace as backup. When I got around to winterizing I used the low point drains and blew out the pipes with a compressor. But when I tried to suck rv antifeeeze into the system the pump would not run. I just left it winterized like that.
My son and his family asked to borrow the RV for a spring break trip. I had brought the water pump inside for the winter intending to test it with my 12 volt trolling motor battery pack. I set up a water transfer bowl and empty milk jug to run it.
Since the pump worked I suspected a leak near the low point drains. I saw a bit of water near there when I drained it.
I connected the pipes without the pump or pressure tank installed. Then ran water through the system with the city water connection. I could not find a leak.
Next step was to reinstall the pump. The way this pump is set up the water input is on the right or outer side and the output is on the left. The pink rv antifreeze valve is on the pipe going into the pump and the tee that held the pressure tank is on the left side of the pump. I had decided to move the pressure tank from the tee through a side hose. It does not matter where the pressure tank is on the water system and I saw examples where the tank was installed off to the side.
To make the new placement of the tee work I had to cut back the existing pex and install an exact amount of pipe connection to make it leak proof. I had to try several combinations but finally got a leak proof connection.
Unfortunately the next day I realized the hose I used to link the pressure tank was leaking so I replaced it with a stainless hose I ran to the store for the morning that the kids were borrowing the RV. Disconnecting the tank creates a heavy spurt of water so I also bought a ball valve so the tank can be removed without spraying all over.
The RV antifreeze valve is also reinstalled and I hope next time I need to, it will suck the antifreeze out and into the plumbing to avoid all chances of freezing.
I was fortunate that there were no other leaks in the plumbing system!