Priming the water pump issues

Revy · 03-24-2021, 08:01 PM

Hi all, first post but I've browsed quite a bit over the past 2 weeks. We just bought a 2019 Jayco Melbourne. It's pretty cold here, and I haven't put water into it yet. We're headed out on our first trip tomorrow and I've run into a problem with the water system. (Im an old school RV guy, I was pretty surprised at all the options at the water tank).

We've filled the tank and I turned on the water pump. Here's where it seems weird compared to my older motor homes (97 Tioga was the one we just sold). The water pump built up to pressure while I was off doing other things. No idea how long it took. I turned on the taps, and air with a bit of water spit out, just like I was used to. Then the air kept coming.... and coming... and coming. I let it run for an hour before I shut everything down. I know this has a larger hot water tank that we're used to, but it seems like a really long time for the pump to not get a steady stream of water to the kitchen tap.

Is there something I'm missing? How long should I run the pump until it blows all the air from the coach lines? Is there a valve that I've missed somewhere? No water is leaking out the bottom of the coach, and after an hour of running the pump, the house tanks are still full. It's coming on evening now. Tomorrow, I plan on pulling out of its garage, opening the slides and crawling under and around to see what's going on.

And on an almost unrelated topic, I read in the manual that you should <never> drive with a full fresh water tank. Seriously? I don't think I've ever launched a journey without the fresh water tank full to the top.

Jagiven · 03-24-2021, 08:32 PM

I suspect it is a cone washer issue.

At the city water connection, there is a cone hose washer. To winterize you have the cone inwards to push the check valve open to pump rv antifreeze into the system.

I suspect the cone washer is still pressing the check valve open. Flip it and I bet your pump will build pressure.

Revy · 03-24-2021, 09:51 PM

Thanks for the reply Jagiven. I checked the cone washer, it was pointed outwards. I removed it and the issue remains. Pump runs, builds some air pressure, and only air comes out the taps.

Cavie · 03-24-2021, 09:54 PM

Quote:

Originally Posted by Revy

Hi all, first post but I've browsed quite a bit over the past 2 weeks. We just bought a 2019 Jayco Melbourne. It's pretty cold here, and I haven't put water into it yet. We're headed out on our first trip tomorrow and I've run into a problem with the water system. (Im an old school RV guy, I was pretty surprised at all the options at the water tank).

We've filled the tank and I turned on the water pump. Here's where it seems weird compared to my older motor homes (97 Tioga was the one we just sold). The water pump built up to pressure while I was off doing other things. No idea how long it took. I turned on the taps, and air with a bit of water spit out, just like I was used to. Then the air kept coming.... and coming... and coming. I let it run for an hour before I shut everything down. I know this has a larger hot water tank that we're used to, but it seems like a really long time for the pump to not get a steady stream of water to the kitchen tap.

Is there something I'm missing? How long should I run the pump until it blows all the air from the coach lines? Is there a valve that I've missed somewhere? No water is leaking out the bottom of the coach, and after an hour of running the pump, the house tanks are still full. It's coming on evening now. Tomorrow, I plan on pulling out of its garage, opening the slides and crawling under and around to see what's going on.

And on an almost unrelated topic, I read in the manual that you should <never> drive with a full fresh water tank. Seriously? I don't think I've ever launched a journey without the fresh water tank full to the top.

About 20 seconds. You have an air leak. Bad or dirty check valve. The pump does not need priming.

Revy · 03-24-2021, 09:55 PM

Where is the check valve located at?

Revy · 03-24-2021, 09:56 PM

And is this an air-pump that pressurizes the water tank? All my previous RV's had a water pump that were just diaphragm pumps that pulled from the bottom.

Cavie · 03-24-2021, 09:56 PM

Quote:

Originally Posted by Revy

Where is the check valve located at?

In the pump.

Cavie · 03-24-2021, 09:58 PM

Quote:

Originally Posted by Revy

And is this an air-pump that pressurizes the water tank? All my previous RV's had a water pump that were just diaphragm pumps that pulled from the bottom.

Nope. It just like your old one.

Revy · 03-24-2021, 10:01 PM

I'll check that in the morning. What's weird is that it builds air-pressure in the lines. I've had bad pumps before, but never one that would build air pressure, but not water pressure.

Revy · 03-24-2021, 10:47 PM

That can't be it. The pump is getting good suction when I remove the hoses. There is no water coming to the back of the pump.

Cavie · 03-25-2021, 03:40 AM

Quote:

Originally Posted by Revy

That can't be it. The pump is getting good suction when I remove the hoses. There is no water coming to the back of the pump.

Either the pump is check valve is bad or the Antifreeze pick up in front of the pump is open. Or you have a cracked fitting. Anything freeze this year???

Revy · 03-25-2021, 07:22 AM

Antifreeze pickup.... now that sounds like a promising lead. I will look for that part and see if it's open. I know it has to be something obvious I'm missing. Normally, unscrewing the feed side of the pump should result in water pouring out. This was dry, even though the fresh tank is full.

Cavie · 03-25-2021, 08:56 AM

Quote:

Originally Posted by Revy

Antifreeze pickup.... now that sounds like a promising lead. I will look for that part and see if it's open. I know it has to be something obvious I'm missing. Normally, unscrewing the feed side of the pump should result in water pouring out. This was dry, even though the fresh tank is full.

It is between the FW tank and the pump.

Revy · 03-25-2021, 11:43 AM

Update! My fresh water tank wasn't full. Bone dry empty. But my black water tank is full.

What in the heck? Ok, no matter where I put the valve switches, the water only fills my black tank. Why would I want to fill my black tanks with fresh water? I'll be crawling under and trying to figure this puzzle out.

Im sure I'm going to figure this out. But jeez, this seems harder than it should

Cavie · 03-25-2021, 11:55 AM

Quote:

Originally Posted by Revy

Update! My fresh water tank wasn't full. Bone dry empty. But my black water tank is full.

What in the heck? Ok, no matter where I put the valve switches, the water only fills my black tank. Why would I want to fill my black tanks with fresh water? I'll be crawling under and trying to figure this puzzle out.

Im sure I'm going to figure this out. But jeez, this seems harder than it should

You need to get your manual out. Go to your wet bay and figure it out. The wet bay may be under the bed.

Jagiven · 03-25-2021, 01:43 PM

Revy, which MH model do you have? There is not a lot of opportunities for air to be getting into the system between the FW tank and the pump's outlet.

You stated your cone water at the water inlet is in the correct position. In theory that means the check valve should be closed. The check valve might not be seated correctly. With your finger or even a key, lightly press on the center, to open and close it, to reset it. Another test would be to thread in male hose cap. This will seal off the inlet if the check valve is leaking air past.

I'm sure you have done this, but have you verified your FW tank is full? Did water come out of your overflow tubes? Tank gauges are not always accurate.

I suspect you do not have a winterizing pick up hose between the water pump and tank. This is more of a TT thing, when you have a gravity fill port. On your MH, I suspect you have the wet bay center where you flip the valves to the correct configuration, for what every operation you are doing/needing. Have you verified your valves are in the correct configuration, when filling the tank and using your pump. May have a loose fitting behind it, or a hose/pipe is not configured correctly, and letting air into the system. Can you post a photo of how those valves are flipped, along with your configuration chart.

Pump, On the pump's inlet there is an filter screen housing. Verify it is on securely, the o-ring is not damaged, or the hosing is not cracked. Could have a loose pipe fitting, between the pump and the tank, so it is sucking air verses pulling water.
If you do have a winterizing pickup tube, you will have one or two valves right before the pump, verify they are switch to FW tank pickup. They are never labeled.

I do not see the integrated pump check valve as an issue. Usually when it fails, you over fill the FW tank when connected to city water as it leaks past.

Good luck

https://www.amazon.com/LASCO-RV554-T...s%2C-1&sr=8-36

edit; I started this reply hours ago. I see your Black tank is full of water. Maybe, the installers hooked up the wrong hose to the wet bay command center. Maybe you just hooked the city water hose to the wrong coupler. It happens, just be glad you did not over fill the tank and back it up into the MH. It is an easy test to verify.

Good luck

Revy · 03-25-2021, 02:13 PM

Problem solved, thanks for all the help!

All my previous motorhomes had one inlet for fill, and one for city connection. The top one was labeled "City Connection" so I assumed the bottom one was for fill. Nope, the unlabeled connection was just for flushing the black water tank. Connected to the top, set the valves where I had them in the first place and she filled right up.

Thanks again, we're hittin the road.

Camper_bob · 03-26-2021, 10:12 AM

Quote:

Originally Posted by Revy

Problem solved, thanks for all the help!

All my previous motorhomes had one inlet for fill, and one for city connection. The top one was labeled "City Connection" so I assumed the bottom one was for fill. Nope, the unlabeled connection was just for flushing the black water tank. Connected to the top, set the valves where I had them in the first place and she filled right up.

Thanks again, we're hittin the road.

Glad you found it!

That was going to be my suggestion after you stated that your fresh tank was dry and your black tank was full. City water was hooked up to tank flush.

Have a safe trip!!

Jagiven · 03-26-2021, 12:45 PM

Quote:

Originally Posted by Revy

Problem solved, thanks for all the help!

All my previous motorhomes had one inlet for fill, and one for city connection. The top one was labeled "City Connection" so I assumed the bottom one was for fill. Nope, the unlabeled connection was just for flushing the black water tank. Connected to the top, set the valves where I had them in the first place and she filled right up.

Thanks again, we're hittin the road.

Glad you got if figured out. From what I have seen the black tank flush port has a black hose connection. Drinking water has a white hose connection.

Camper_bob · 03-26-2021, 01:59 PM

Quote:

Originally Posted by Jagiven

Glad you got if figured out. From what I have seen the black tank flush port has a black hose connection. Drinking water has a white hose connection.

On mine they are both physically exactly the same; both black with black covers. The fresh connection resides a couple inches directly above the tank flush connection.

It could be that the "technician" at the factory applied the labels wrong on OP's unit. I've seen that happen before on tank valve handles. The picture was of the waste valve handles; the grey handle had a "black tank" sticker above it, and the black handle had a "grey tank" sticker above it.

You may also like: