Using water pump while hooked up to faucet

[drayweb]

Last weekend I hooked the hose to my camper and tried to run water through the hot water faucet. When I saw that nothing was coming out, I turned on my water pump and now the pump doesn't work. I realized now that I should have waited for the hot water tank to fill up. I have a water pressure regulator on the hose spigot, so I don't think there was too much pressure in the line to ruin the water pump.

[JohnB]

Hi,

H'mm, your issue might be an easy one to correct, or not pending on what does not work on your pump given the way your camper had water in it when you started the pump.

1. Does the pump motor run, just the pump does prime and start pumping water? This can be a procedural issue and I "think" the one you have.

2. Or, is the motor not turning? This can be a mechanical or electrical failure and that cause we need more info on before how to get out of it.

The first problem where the pump runs but does not pump can be an air locked pump (dry locked pump) causing it not to prime. This happens often and folks do not realize what they did to cause it. Or how to get out of it or not have it happen again.

I'll explain a little how this air lock happens and you tell me if this fits to what issue you had.

Background: These RV style water pumps are made to pump water. They really do not pump air very well. But, they have to be able to pump some low level of air to create enough suction to draw water up the hose from a full fresh tank to prime the pump the first time when the camper piping is "empty".

Here is how I suggest folks start the water pump to help prevent the air lock situation. You may be doing this all the time, and if so, good. But here are the reasons on why to do it.

Lets set the stage for a normal water system startup using the fresh tank and water pump and how I suggest you start up the system.

The camper piping is empty, the water pump is empty, the water heater is empty, the fresh tank is at least half full or totally full. This is a common start to a camping trip when the camper is drained.

Look at your floor plan and see which faucet is the closest to the water pump. Open the cold water faucet wide open "before" you turn the pump on. This is very important. You can also open the hot water faucet too if needed on some systems. By opening this closest faucet, you are creating an air vent to allow the air being purged out by the pump at startup to escape freely and not compress in the piping.

Then turn on the water pump. The pump will start with creating suction and pump air for a short period of time until the water draws up the hose and primes the pump. The air in the water pump that is being pushing out of the pump will vent out the open faucet. That venting helps the pump prime. Once the pumps starts pumping water at a good rate, then you can close the faucets and it will pump/jam water into the system now no problem.

Most of these water pumps do not have the ability to pump air into a closed piping system. Some may get lucky and their piping will let allow the pump to compress enough that the pump can still prime with water. But there are those that have pumps that are aged or the piping is such the pump cannot pump air into a closed system very well. What happens is, the pump dry locks with air inside as it cannot push it out through the closed piping due to the back pressure in the piping. And the pump does nothing then but spin, not sucking any more water and for sure not pumping water.

By you having the camper half or totally filled with water in the piping and more then likely the faucets closed, the pump dry lock issue was magnified. The pump cannot pump the air out of the water suction hose and draw water up into the pump as it cannot push the air into a water filled and closed system. The pump becomes dry locked as we call it.

If this is what you had happen, the fix is not that hard. The easy way if you are lucky. Start with the pump off. Open the hot and cold faucet closest to the pump. Then turn the pump on, it may take a while to catch and then it will start pumping and all is well. Only if you are lucky. If a minute has gone bay and still nothing, then you are not lucky and need to do the longer method that usually will solve the problem.

The long way. Have the pump off. Next open the low point piping drains, open the water heater drain, and open every faucet in the camper to let air into the piping. Do not forget to open the outside shower faucet if your camper has one. Let all the water drain out of the camper piping and water heater. Put the drain plug back in the heater, close the low point drains, close the outside shower faucet. Leave the bath sink and kitchen sink hot and cold faucets wide open.

Have the fresh tank full of water to lower the suction head needed for the pump to lift. Then, turn on the pump. It should catch in a short while and it will start pumping water and blowing air out the faucets once the pump prime starts. Once the water starts pumping you can start shut off the inside faucets or air bleed them out, then shut them off. The pump should then work OK.

Does this seem to fit with what happened to you?

Let us know how this goes. Hope this helps

John