Air in the water pump inlet line

[MGB]

I have a 2017 GD Reflection that I purchased used two years ago at that time we rarely camped without hook ups but now we primarily boondock. I noticed at times while using the fresh water pump I would get sputtering air out of the water fixtures so I assumed there was a leak in the suction line going to the fresh water tank or a valve leak in the nautilus system but after searching for the problem I couldn't find the problem so I decided to do a test and purchased some clear 1/2" hose and removed the fresh water line to the tank and replaced it with the clear hose that I dropped into a 6 gallon water jug, by the way I replaced the pump with a new one and the problem continued anyway when turning the pump on and getting rid of the air in the new hose it seemed to work UNTIL I waited about 30 minutes and the problem came back so that eliminated the fresh tank line as the problem but what I did notice was when not in use the water would drain out of the clear hose leaving a air pocket so my question is do these fresh water systems come with a check valve to stop the water draining back to the tank?

[Country Campers]

The pump should have a check valve on the output side. Check the clear bowl and screen on the input side. The clear bowl has been known to get small cracks, check the seal as well.

Brian

[TedS]

No, there is no check valve in the suction line from the tank to the pump.

[JBill9694]

It sounds like the pump is losing its prime. The usual suspect for this is that the intake is not submerged enough. However, MGB did not mention seeing any vortex in the bucket during his testing. So I went looking, briefly, for how the pump self-primes without success. If anyone knows, pitch in.

From previous threads I suspect that it has something to do with the orientation of the screen under the clear dome and that this needs to be facing up.

[Jlawles2]

Agree with John. Pump is loosing prime or the line leading to the pump is somehow admitting air. Usual suspect locations are fittings for air leaks. Check the filter and it's housing as mentioned.

In the mean time you may want to do a pitcher test. You will need a clear container, the taller the better, and a tub of some sort that the container open end will fit into. Fill the tall container with liquid (you may want to use the sink full of the same water in the holding tank) and place upside down in the tub with 1/2" or so of water covering the opening. Set somewhere that it will not get knocked over and note any air in the top of the container. Wait XXX hours and observe if the air has changed. If there is more air you have an issue with the water in the tank containing an excessive amount of dissolved gas and when it's under vacuum (the pump to tank line holds vacuum slightly) the gas will "boil or appear" out of the liquid. Long shot, but I have seen stranger things.

[TedS]

Prove or disprove the suction filter as the leaking culprit by removing it and connecting the intake hose directly to the pump and test if the hose holds its water or not. If it holds water, the filter is the culprit. If the hose loses the water column, the hose fitting or pump gasket is leaking air.

[MGB]

I installed a check valve in front of the pump filter with no change this is a brand new pump but I will check the pump filter but the old pump did the same thing. I can only assume at this point there is a problem with the fresh water tank or a split in a water line somewhere I will keep digging I wish the water tank was easier to get to.Thank you folks for your help.

[TedS]

The suction hose is connected to the water tank, low, near the tank drain. I suppose that fitting could be loose and sucking air. That could be the leak common to all your tests, so far.

[Yoda]

I installed a check valve in front of the pump filter with no change this is a brand new pump but I will check the pump filter but the old pump did the same thing. I can only assume at this point there is a problem with the fresh water tank or a split in a water line somewhere I will keep digging I wish the water tank was easier to get to.Thank you folks for your help.

The pump suction line should be very close to the frame before it swings over to going through the floor to the pump. You should be able to undo the coroplast belly fabric between the fresh water tank drain valve and where your pump is. Then by pulling it down a bit be able to get a look at how the line us run, That suction line is the same line the power fill is attached to, so you might want to start at the back of the naturalist panel and identify the power fill line and where it attaches, It could be in that run there might be a path for air to get in.

Just brainstorming here
Keith

[MGB]

Info for those who were kind enough to help me fix this problem after speaking to a local RV repair manager here in Quartzite Arizona he suggested that the problem is almost always the strainer attached to the pump, I explained that this is a new pump and he said it doesn't matter remove the strainer and try it if the problem goes away there was your problem. I returned removed the strainer and what do you know the problem went away so I guess I have to figure out how to seal up the strainer or leave it off.

[Country Campers]

MGB

Did you remove the entire strainer from the pump inlet, or just the strainer screen that is inside the bowl?

Brian

[MGB]

I removed the entire part.

[Country Campers]

I removed the entire part.

I would guess that the bowl has small cracks or the seal on the bowl is faulty. You can get a complete replacement online or at your local RV shop.

Brian

[Reacher]

I've been able to fix this problem before by replacing the "O" ring and applying plumbers grease before re-assembling (if the plastic bowl is not cracked).