NEED HELP REPLACING WATER LINES

Try googling "RV plumbing" or "RV water systems" or similar. There is a lot of information to help educate you on what to look for.

Our pump wouldn't prime unless the water tank was full to overflowing. It got quite a bit better when I finally replaced its rubber diaphragm.

Enjoy figuring it all out; it is enjoyable and very satisfying to understand the whole thing and be able to fix things!

Most RV's have hot and cold water low point drain valves used in draining all water from the lines. The valves are usually located behind a panel near the bathroom or elsewhere. These valves must be completely closed when running the water pump to pressurize the system and pump water to the faucets and toilet. There are small diameter tubes that water drains from underneath the RV. All tubing must be connected to faucets etc. without any leaks for the electric pump to pump water and to shut off automagically when faucets are closed. All faucets must shut off without leaks. You may need to replace the electric water pump with a same gpm capacity pump. You may want to install a more powerful pump for stronger shower spray. You may need to install an Intellitec device when installing a higher amp pump. Low water pressure when hooked to city water supply may be due to a faulty one way valve assembly on outside of your RV. Check any filters on faucets for build up of lime deposits. There may be a clogged flow restrictor in your shower head and toilet supply due to lime deposits. You might get help with RV plumbing from a local RV supply/repair place with knowledgeable people. BTW all electrical connections and remote water pump switches must be good and your 12 volt house battery must good and fully charged for pump, furnace and AC thermostat and appliance controls to operate properly. Getting an old rig's innards working properly can be a challenge unless you are experienced with RV electrical, propane, and plumbing systems. Good Luck! There are some good You Tube videos on RV repairs and upgrades as well as maintenance.

Three lines under sink should be Hot, Cold, and line to feed all other items. Toilet, Hot Water, Water Pump, Lavatory Basin, Shower, and other items that use water.

Diagnosing a problem has to start from the beginning. You need to access the water tank and trace/follow the lines to the pump. A leak will not allow the pump to develop pressure. From there you need to trace the line coming from the pump to the sink and so forth. Water lines are sometimes behind cabinets, pull the drawers out and look. It is tedious but necessary. I prefer pex tubing and a clamping device with their collars, they will never come loose. You have some city water which is a good sign, be vigilant and look for leaks, inside and out. Other than starting from the basics there are no diagrams out there that I know of that explain how or where they ran their water lines during the build. Also be sure the water pump screen/filter is clean.

Matila,

I wish you the best of luck. I know nothing of RVC units.

Your pump might need to prime. You can help this along by disconnecting the discharge with the pump running. Just be sure to have someone by the switch.

No flush water to the pot could be another valve that you have not found. It also could be that the valve at the pot is broken (frozen and damaged) so it will not open.

Low pressure on city water would tell my that something isn't set the way it should be. There may be a selector valve for tank/city that is also why the pump isn't doing anything for you.

Matt