Funny water pump leak

only leaks when pump has presure on the lines, might sit and watch it ,could be gasket at strainer. cracked strainer housing. loose clamp,and on,an on.

Or maybe the system has to sit unpressurized for a few days and then leaks the first time it's pressurized.

Posting some pictures of your setup might help us give better answers to what might be the issue.

From what you told us, there is one possibility that might cause the puddle to leak and then not leak. Since I can't see your setup, consider this a generic answer as I have seen this on any connection using a swivel fitting in an RV setting.

At the piping ends of most RV style water pumps are swivel fittings to allow you to screw the hose or piping onto the pump and not have to spin the pump to get them to go on. Many of those fittings are in the PEX style family of swivel fittings. The fittings look like this, your brand might be different.



On the end of the fitting is a cone washer, look like this,




This is the cone washer by itself as a replacement from Flair-It company.


Those swivel fittings sometimes loosen up and drip. Sometimes the cone washer was jammed sideways when installed and did not seat right and they drip. When the camper get old, like 10 plus years etc. the washer gets a little brittle some times and being compressed long enough start to drip.

Assuming your pump has a fitting similar to the ones I showed above, first just try and tighten the fitting. Most times that stops the leak. If that does not stop the leak, then change out the cone washer.

Now showing up on newer water pumps they have swivel fittings with no cone washer, they use a plastic nut and inside the fitting wedge cone to create the seal, they too can leak if they are loose. There is no cone washer to replace, but the loose fitting or a damaged wedge cone can leak. The fitting looks like this from Shurflo https://www.amazon.com/SHURFLO-244-2926-Straight-Wingnut-Adapter/dp/B002IZJ7CW/ref=asc_df_B002IZJ7CW

I find it helpful to put dry paper towels under a suspect leak area. The monitor it often, and have the pump on to pressurize the system. If you catch the drip in the early phase of the leaking, then you can see where on the paper towel it dripped and help back into where it came from.

You did not say if you were on city water or only using the pump and fresh tank. Pump leaks can happen from both water supply areas, but city water hookups can have very high water pressure that can aggravate a fitting leak more then the onboard pump can. Have you noticed this problem more on city water or using the onboard pump?

Hope this helps

John

Answering a couple of questions about my leak:

This is using the pump. I rarely connect to city water.

I tried the paper towel trick, but I have never caught it in the act. The towel is either completely dry or soaked. I tried putting a little tray under the pump. It does catch the water, but I can’t tell if is inlet side, outlet or the pump itself.

This is a brand new trailer. We saw the leak 3 times on a 10 day camping trip. The pump was on the entire time. It may be that the leak only happens when the water heater is on, but still not every time. The heater is nowhere close to the leak.

I’ve seen the leak twice in the week since the trip. Both times it happened like this: I decided to shower i the trailer to see if that caused the leak. I turned on the hot water, and waited. When I went back out, the spot was already wet. Dried it off, took a shower, and checked it again. No additional water after the shower.

In order to post a picture, I need to put it somewhere else on the web, and then link to it, right? I’m not sure where to put it.

^Just google “rvnet photo posting”. TAkes you to an old thread here with a link.
From there it’s pretty easy. A little clumsy and not convenient but not difficult.

Your water issue is perplexing though, especially if you can’t catch it in the act or see evidence of where it’s leaking from.

One thought, maybe get a helper and cycle the pump on off, drain pressure from lines each time. Should be able to do that repeatedly in not a lot of time. And just watch that sucker until she squirts!

This is good extra info, see below.

waynefi wrote:


This is a brand new trailer. We saw the leak 3 times on a 10 day camping trip. The pump was on the entire time. It may be that the leak only happens when the water heater is on, but still not every time. The heater is nowhere close to the leak.

I’ve seen the leak twice in the week since the trip. Both times it happened like this: I decided to shower i the trailer to see if that caused the leak. I turned on the hot water, and waited. When I went back out, the spot was already wet. Dried it off, took a shower, and checked it again. No additional water after the shower.

In order to post a picture, I need to put it somewhere else on the web, and then link to it, right? I’m not sure where to put it.

On posting the pic, hoping someone will jump on on this, RV net has a new pic posting system you can use if you do not have your own photo hosting site. I have my own hosting site so I just link them in so I do not know the new RV net system.

But, I can help with the blue wording up in your response. First off, when the water heater heats/runs, the water in the piping and tank expands from thermal expansion. That expansion of the water has to go somewhere, in this case it builds pressure in the system OR it expands into the air cushion created inside the water heater. Not sure what brand water heater you have, Suburban or Dometic/Atwood but they both create an air cushion in the top of the heater when the water fills the "first" time from the heater being empty to help not create too much pressure.

Over time, use or towing down the road, that air cushion dissolves and then, there is no place for the thermal expansion of the water to go other then build pressure. And it can build pressure all the way to make the safety relief valve weep out water to relive the close 150psi pressure. As soon as you open any faucet, that pressure will drop almost instantly to normal pump pressure and then when using the shower or faucet the pressure is more normal.

The only way to re-create the air cushion is bleed off the pressure in the system, let the heater cool down some and drain out 2 to 3 quarts of water while having the safety relief valve open to allow air back in. Then let it refill with the pump and your good to go until the next time the air cushion dissolves. This is a standard RV issue when no expansion bladder tank is in the system.

The above process will only take care of high pressure that makes the relief valve weep. Go outside have a look at the relief valve and see if any water drips/drops are outside after you heat water from cold to hot. If there are no drips, then the expansion pressure is not getting up to 150psi, it may normally only go to 120 to 130 psi and not trip it. But the pump fittings are seeing that 120 - 130psi until any faucet opens.

That said, the water system should be able to handle that high expansion pressure and not drip, like your water pump is. Addressing the water heater expansion issue will not fix the issue at the pump, but now armed with this info, maybe try this. Let the heater cool down, run cold water through it if needed and then turn the heater back on while watching the dry paper towel trick. It may take a good 30 to 45 minutes if you have total cold water in the heater, but you can at least create the higher pressure even if it is not tripping the relief valve to see what is dripping at the pump. You can also check the relief valve for dripping when the heater shuts off. Just do not open a faucet or flush the toilet during this test until the test is over or you will loose all that higher pressure you created with the water heating.

Hope this helps and let us know how this comes out.

John

In order to post a picture, I need to put it somewhere else on the web, and then link to it, right? I’m not sure where to put it.

You can upload the picture here and then post it. Go to the DIY topic and the instructions and link are right there. Quick and easy.

You might try checking the head screws to make sure they are tight. Mine loosened up over time and would leak as yours is doing; I gave them a quick tightening and all is well now. Good luck and happy camping!

waynefi wrote:

In order to post a picture, I need to put it somewhere else on the web, and then link to it, right? I’m not sure where to put it.

A fast and easy way to include a photo in a forum post. Just drag-n-drop a photo, and copy-n-paste the image link in your message post. Uploads photos directly to IMGUR.com servers. Automatically resizes photos to the max recommended by the Open Roads Forum. Includes a thumbnail preview, and also provides an optional link to permanently delete the photo. The WebApp is available at http://photoposting.is-great.net

I agree with JBarka. When the W/H heats from cold with no water use the pressure can spike and cause a leak. Mine sure did.

Best solution is a small expansion tank such as ShurFlo.

https://www.amazon.com/SHURFLO-182-200-Pre-Pressurized-Accumulator-Tank