Air getting into water pump?

[Camper_bob]

So after my trailer has been in storage, it takes A LOT (a long time) for the water pump to pick up prime, and it seems to be getting worse. This last time, it took long enough that I went looking for problems. I removed the screen before the pump and cleaned what little debris that was in it out, reinstalled and the pump fired right up and picked up water. I'm not convinced that was the only problem though; there wasn't enough in my estimation to block water flow enough to keep the pump from priming.

I've read through A LOT of water pump threads and I found an idea that I could put a little water in the bypass hose to get the pump primed. That's all good and well, and I'll try it next time I face the problem.

My dad said that I'm probably getting air in the line before the pump. I thought that to be unlikely until I read some of the other threads here. But I will be checking that option shortly. I'm going to also install an accumulator tank this week, so I'll just make sure all the connections are good 'n' tight on both sides of the pump when I do that.

My questions are these: Has anyone ever solved a pump priming problem by finding an air leak on the non-pressure side of the pump?

Also, for those who winterize with air, do you put a little AF in the pump to keep the seals "wet"? My dad also said it's bad to store the pump dry, and that makes sense to me; rubber that has been wet doesn't like to be stored dry. That would be relatively easy for me to do since I'm putting AF in the traps anyway.

Thoughts?

[RVhiker]

Originally Posted by Camper_bob

My dad said that I'm probably getting air in the line before the pump. I thought that to be unlikely until I read some of the other threads here. But I will be checking that option shortly. I'm going to also install an accumulator tank this week, so I'll just make sure all the connections are good 'n' tight on both sides of the pump when I do that.

My questions are these: Has anyone ever solved a pump priming problem by finding an air leak on the non-pressure side of the pump?
Thoughts?

My pump was pumping a mixture of air and water and I found I had an air leak at the strainer - there was an "O" ring missing and I found one that would work at a hardware store. Also, you could have a leak at a crimp ring or screw clamp somewhere, or a winterizing valve could be open and allowing air to get sucked in. I think your Dad has the basic problem correctly diagnosed.

[motorbreath]

I have the same problem with my 2015 28BHBE and I have tried several fixes, but no matter what the pump will eventually lose prime and will not reprime without running the water for a second or two.

This winter I am working on enclosing the underbelly using corrugated plastic and clip nuts. Once I have this done the next thing on my list is moving the pump into the underbelly, if possible. This will hopefully have two benefits, the pump will prime much easier and the noise and vibration from it running will not be felt inside the trailer as much.

I realize it is a relatively drastic move, but I think it is worth it since I really like the trailer and plan on keeping it for a long time!

[hboy]

I have the same trailer too. My problem seems to be the low point drains under the bath sink. One of those boogers seems to not want to close. Occationally when the pump seem to take a while to prime, I will play with that valve under bath sink and it will not be closed.... Probably not your problem, but that whats happening here.

I use air to winterize, then some pink stuff too.

[motorbreath]

Those valves always seemed odd to me, some sort of gate valve, I think they could be easily replaced with a ball valve. Home Depot sells reasonably priced PEX tools, valves, etc, but that particular spot under the bath sink looks very very busy for me to play around in

Originally Posted by hboy

I have the same trailer too. My problem seems to be the low point drains under the bath sink. One of those boogers seems to not want to close. Occationally when the pump seem to take a while to prime, I will play with that valve under bath sink and it will not be closed.... Probably not your problem, but that whats happening here.

I use air to winterize, then some pink stuff too.

[Camper_bob]

Thanks for the feedback guys!

Usually getting prime for me is MUCH more than a few seconds. Last time, it never actually got it on its own and I let it go for at least a few minutes each time I tried. DW brought it to my attention during break-down last trip out. I will put her on tank water toward the end after I disconnect city water; this time she couldn't get water, and this hunt began.

I don't think it's the LP drain valves under the sink. If that were the case, I would likely see a leak there when the system is under pressure. No leak, so I ruled that one out. HOWEVER, those T-valves are garbage IMO. At some point I'll replace them with ball valves.

I'm leaning more toward the valves just before the pump on the winterizing kit. I have heard that the plastic 1/4 turn valves found on the winterizing kit are also sub-standard equipment and subject to letting air pass (these are the same valve type found behind the WH for the bypass). My problem there is I don't want to drop coin on PEX tools so I can take that whole thing apart and replace the valves. It's my estimation I would need the tools just to DIAGNOSE the valve since all these clamps are one-time use crimp clamps. So the natural solution looks like "Sharkbite" fittings/valves? I was looking at Home Depot online yesterday, and couldn't find a 1/2" to 1/2" push to connect shut-off valve. Seemed like they had everything BUT that though, so I might have better luck actually going down the street and looking at the shelf at the brick 'n' mortar.

Anyway, I got my accumulator tank last night, but didn't get a chance to mess with it at all; we had to wrap Christmas Presents and bake cookies. Upside on that was I got to enjoy a nice glass of scotch during that project!

One other thing of note: I ran the sink faucet last night after the system sat over night, and the faucet ran A LOT smoother. Yesterday when I finally got things running, the pump sounded like a jack hammer and the water came out in rapid bursts (like a machine gun on full-auto). This is odd to me, but makes me lean even more to those valves before the pump...

Just a guess at this point, but the likely result of this whole thing is me saying "F-it" and replacing ALL those crummy plastic valves.

[RVhiker]

I've found it to be economical to buy a (cheap) PEX crimping tool; I've had to use it several times on my trailer. The stainless steel clamps are cheap. Overall much less expensive than Sharkbite fittings, and I think easier to use. Here is one PEX crimping tool (clicky) which I think can be had for much less on-line.

[oldmanAZ]

Originally Posted by Camper_bob

Thanks for the feedback guys!

Usually getting prime for me is MUCH more than a few seconds. Last time, it never actually got it on its own and I let it go for at least a few minutes each time I tried. DW brought it to my attention during break-down last trip out. I will put her on tank water toward the end after I disconnect city water; this time she couldn't get water, and this hunt began.

...snip...

One other thing of note: I ran the sink faucet last night after the system sat over night, and the faucet ran A LOT smoother. Yesterday when I finally got things running, the pump sounded like a jack hammer and the water came out in rapid bursts (like a machine gun on full-auto). This is odd to me, but makes me lean even more to those valves before the pump...

Just a guess at this point, but the likely result of this whole thing is me saying "F-it" and replacing ALL those crummy plastic valves.

Since you are still diagnosing the problem...
Do you (or anyone else) know if there a check valve ahead of the pump that should close when switching from city water to tank water? It seems odd that an air leak would change after sitting over night; a sticking check valve might do that, however. I'm just guessing, but it seems likely a check valve of some kind might be in the system when city water is connected.

[Camper_bob]

Originally Posted by RVhiker

I've found it to be economical to buy a (cheap) PEX crimping tool; I've had to use it several times on my trailer. The stainless steel clamps are cheap. Overall much less expensive than Sharkbite fittings, and I think easier to use. Here is one PEX crimping tool (clicky) which I think can be had for much less on-line.

Thanks! That's about $20 cheaper than what I was finding yesterday I think. I guess I really should look into this. I have just about every other tool I need to work on my trailer, I should make the investment and complete the set perhaps.

Originally Posted by oldmanAZ

Since you are still diagnosing the problem...
Do you (or anyone else) know if there a check valve ahead of the pump that should close when switching from city water to tank water? It seems odd that an air leak would change after sitting over night; a sticking check valve might do that, however. I'm just guessing, but it seems likely a check valve of some kind might be in the system when city water is connected.

There is not one that I could see. Now, granted, the last time I was down there fussing with stuff the other day, my son (14 months, just started walking regularly) decided to take a nose dive out the screen door and down the stairs making a not-so-soft landing on the concrete driveway, head first of course. He's fine, I got to him before he even knew what happened, but my inspection/diagnosis of the water pump stopped immediately, and unfortunately I haven't had a chance to get back in there for more trouble-shooting.

Maybe I'll look into investing in some PEX tools while I'm at the hardware store getting a latch for the screen door! LOL!

Edit: I did consider the check valve on the city water as a possible culprit as well, but the way it's acting, I'm convinced the problem is on the low-pressure side of the pump. As for why the pump is acting entirely different yesterday as opposed to the day before, at this point I have no idea...

[TCNashville]

Bob, just a couple of things. Would it be possible for someone to put their thumb over the open end of the winterizing valve and see if it pumps up? [valve not totally sealing] Or it could be the fresh water valve which appears to be open but not totally open. This would cause hammering. Or it could be the fresh water line pickup in the tank is partially clogged, also causing hammer. There could be a hole in a line somewhere between the fresh tank and pump. If you've ever removed the lines from the pump, there's a 1/4" long, circular gasket that must be in there or she'll suck air/water. Lastly, the seals have dried out in your pump requiring replacement. All this assuming the water heater is on bypass.

[Camper_bob]

Originally Posted by TCNASHVILLE

Bob, just a couple of things. Would it be possible for someone to put their thumb over the open end of the winterizing valve and see if it pumps up? [valve not totally sealing] Or it could be the fresh water valve which appears to be open but not totally open. This would cause hammering. Or it could be the fresh water line pickup in the tank is partially clogged, also causing hammer. There could be a hole in a line somewhere between the fresh tank and pump. If you've ever removed the lines from the pump, there's a 1/4" long, circular gasket that must be in there or she'll suck air/water. Lastly, the seals have dried out in your pump requiring replacement. All this assuming the water heater is on bypass.

All VERY good suggestions!

Thank you! The FIRST thing I did (still at the park immediately after my wife told me there was no water) was switch the valves over to "Winterization" mode and put my finger over the hose; no suction at all. And the pressure side of the pump had water because this was right after I disconnected from city water after using the trailer for 2 days.

Right now, it's working better than when it was new. The ONLY thing I have actually done is remove the particulate screen on the low-pressure side of the pump and clean it. It was not dirty enough to block flow from what I could tell, but as soon as I took it off, rinsed it out and put it back on, it picked up water. Could be coincidence.

Immediately after it started working again, the pump was hammering while I was testing it (standing there scratching my head). Then I decided to try to quiet things down some and put foam pipe insulation around some of the piping. When I was finishing up that project, my son fell out of the trailer down the stairs onto the concrete driveway (he's just fine, hardly noticed, just a little startled). That's the last I got to work on it. I ordered an accumulator tank on Amazon that night; that was Sunday.

Night before last, I was loading some things up, and needed to wash my hands. Pump worked like a champ. Relatively quiet, smooth, plenty of constant pressure, no hammering. Last night I ran the faucet for about 3 minutes just to see that it would continue on that way, and it has. My FW tank has been full since that first screen cleaning, and I wanted to drain some off so as not to carry a bunch of water I don't need this weekend.

So the frustrating part is that it seems to be intermittent. If I leave the trailer for a day, everything stays happy. No leaks, the pump comes right up, builds pressure, runs smooth. With time constraints, all I can do is think about this stuff. I won't get a chance to really put my hands on it and diagnose and work on it until next week.

Part of me wonders if it's the seals in the pump drying out in storage. That's why the question about putting a little AF in the pump during storage. I use air to winterize and drain ALL the water out every time I store it, so that pump is stored pretty much dry every time. I'm wondering if perhaps I need to change my routine a little?

[mike837go]

Unquestionably, a 'false prime' from the antifreeze pickup helps tremendously!


Fill the freshwater tank.
With the faucets closed, and the water heater still in winter mode, set the valves to draw from a gallon or so bottle using the bypass.


Run the pump to pressurize using the water in the bottle. A gallon should be enough. If not, turn off the pump before it draws air.


Change the valves to draw from the tank. Finish pressurizing if needed. Then include the water heater and finish purging the air.


Refill the fresh water tank.

[Camper_bob]

Originally Posted by mike837go

Unquestionably, a 'false prime' from the antifreeze pickup helps tremendously!


Fill the freshwater tank.
With the faucets closed, and the water heater still in winter mode, set the valves to draw from a gallon or so bottle using the bypass.


Run the pump to pressurize using the water in the bottle. A gallon should be enough. If not, turn off the pump before it draws air.


Change the valves to draw from the tank. Finish pressurizing if needed. Then include the water heater and finish purging the air.


Refill the fresh water tank.

That may be my process with one small tweak. Since even from the winterization hose, I don't get suction, I would have to add water to that hose for the "false prime" with a funnel via gravity.

I'm still curious if I'm doing damage to the pump by storing it dry. Wondering if that's what's causing my issues.

Does any one else store with their pump dry?

[mike837go]

Originally Posted by Camper_bob

That may be my process with one small tweak. Since even from the winterization hose, I don't get suction, I would have to add water to that hose for the "false prime" with a funnel via gravity.

I'm still curious if I'm doing damage to the pump by storing it dry. Wondering if that's what's causing my issues.

Does any one else store with their pump dry?

According to the manual, they can be run dry indefinitely. Until the battery runs out or the wobble plate wears at the bearing.

I've had the older pumps apart. The rubber bits do dry out over time. But since one side is ALWAYS exposed to room air, I would suspect that leaving the pump empty won't be a problem. However, if the pump has any clear water in it when it is exposed to below freezing temperatures, small internal bits of plastic, nylon or rubber will be damaged.

It's much better to fill the pump with anti-freeze than rely on a blow out. There are no drains on the pump.

[Camper_bob]

Originally Posted by mike837go

According to the manual, they can be run dry indefinitely. Until the battery runs out or the wobble plate wears at the bearing.

I've had the older pumps apart. The rubber bits do dry out over time. But since one side is ALWAYS exposed to room air, I would suspect that leaving the pump empty won't be a problem. However, if the pump has any clear water in it when it is exposed to below freezing temperatures, small internal bits of plastic, nylon or rubber will be damaged.

It's much better to fill the pump with anti-freeze than rely on a blow out. There are no drains on the pump.

Good deal. Thanks Mike.

This weekend, it all worked flawlessly. I still have the accumulator tank in the box until I get some time to install it the way I want. I want to isolate it and the pump on a vibration dampening apparatus, and I'm still deciding exactly how I'm going to do that.

With the holidays upon us, I'm struggling to find time to get out there and tinker. I probably have a full day of work to do on the trailer including inspect and wash roof, wash/wax outside, detailed deep cleaning of inside, install another light in the front pass-thru storage, install and plumb accumulator tank, etc.

I think we have maybe one or two trips left before she goes to sleep for the Spring and then I won't have her back home until late April or May.

[Camper_bob]

Update:

After storing the trailer for about a month, I brought it home for a trip that has since been scrubbed due to illness. Anyway, before we decided to scrub the trip, I wetted down the trailer as I always do. I connected city water to pressurize/fill all the water lines and the water heater. Then I filled the fresh tanks with ~35 gallons (my standard traveling complement of fresh water for "incidentals"). This is all my normal procedure; I do it EXACTLY the same EVERY TIME. I disconnected from city water source, and turned on the pump. I opened the kitchen faucet, and in about 45 seconds or less, the pump picked up prime and began pumping away like a champ! Which is great, right? But WHY did it work this time right away whereas before it took significant coaxing? I hate intermittent problems.