Water pressure very high at sink after draining/filling freshwater tank (not using city water)

danp212

Greetings everyone, longtime reader and new T@B owner very excited to finally join and contribute to this awesome community!!

 Over the past 2 days I just followed all owners manual procedures for sanitizing the freshwater tank on my 2017 320 S Max, however am having a tricky time getting water system back to normal after flushing the freshwater tank a few times after the bleach sanitization process. Keep in mind this whole process is only using the fresh tank onboard system, and at no point have I hooked up to city water.

My main issue seems to be unusually high water pressure coming out of the sink faucet, especially when initially turning the faucet from off to the on position. I seem to have gotten all the air out of the lines just fine, but I find myself having to be extremely delicate with the faucet in order to prevent high pressure water splashing everywhere in the kitchen area. The pump switch is on at this point, but the pump only runs for a bit when using water as per usual operation. 

The pressure buildup is so high that a couple times this morning I slowly opened up the faucet knob all the way, and the small faucet head nozzle actually BLEW off and into the sink!! Luckily it doesn't have threads on it and only uses a rubber o-ring, so it simply snaps back in place (maybe this is a safety feature?) 

The other thing I am slightly concerned about is when the pump is running and pressurizing the system, I hear a gradually increasing hissing sound for a few seconds before it turns itself off. I don't seem to remember this happening previously but I can't exactly remember. Its not a super loud hissing sound but I just wan't sure if it was normal operation or not. 

Has anyone else had issues with their freshwater system pressure being extremely high, and even blowing the faucet nozzle off at times? 

Homebodyatheart

No, but @Dalehelman, @Verna ,@ericnliz, or @Michigan_Mike any ideas?  Calling the factory direct and talking with them is also a very good idea as they know the system well. I look forward to hearing what your solution is. Good luck with it!

Sharon_is_SAM

Sounds like you have a partial obstruction and you may not be able to see where it is either.  Check the outlet of the pump for starters.  

DurangoTaB

That's an odd one...usually too little pressure with that small noisy pump!  I presume equally high pressure out of the shower and/or toilet?  No pressure problems with the pump switch off?  

Roamey

"The pump is designed to pump the system up to about 40-50 psi and then a pressure sensing switch mounted on the pump shuts the pump off until the pressure drops."  This from a Web search about the pump pressure. The internal bypass and regulater are built into the pump located above the toilet behind the panel cover. 

danp212

I went ahead and sent a message to nucamp so hopefully they will get back to me with some insight. 

Could be a partial obstruction post pump or even in the sink faucet line. When I checked this morning the shower head didn't seem to have the same pressure buildup issue. Because the faucet head nozzle kept blowing off, I also wonder if the tiny little holes in the nozzle are restricting flow and causing the pressure build. Didnt look like any of them were clogged but I'll remove the nozzle tomorrow and retest.

Heading to Big Basin State park for the weekend so will have plenty of time to try and track this down even further. 

JohnDanielsCPA

I had the same experience.  It seems the problem isn’t so much from water, but from the air in the lines.  Once the air is purged and the lines are pressurized, the water seems to flow fine.  There are a couple things I have done to reduce the pressure.  First, if you can, hook up to city water and use the shore hookup to purge your lines (including the ALDE) of air.  If you can’t do that, just turn the kitchen faucet on to a lower setting so the air still purges, but it doesn’t force it through the faucet with such pressure as to blow off the faucet head nozzle.  Anyone else have any other thoughts?  Let us know what NuCamp says.

Homebodyatheart

I seem to remember holding the toilet flush handle open a while to bleed the lines of air earlier this season. Would that help? Good luck!

Michigan_Mike

Sounds like some type of an obstruction in the line if the shower head is producing nominal pressure?  I'm wondering if there would be a means of blowing some air back through the line with a compressor and then checking the pump filter or unhooking the lines at the pump and forcing air back through them might clear things up? The pump should only be pushing 30-35 PSI as I believe my original factory install was rated for around 30 PSI as I recall?  

And agree, try hooking up to the city water connection and see what happens and if that changes things up.  

Sharon_is_SAM

Sorry if this has been mentioned, but have you unscrewed and cleaned the pump filter?  The metal filter in there can be moved and a little tricky to screw the cup back in place.

danp212

So after a weekend dry camping run in the T@B I was able to get the water pressure working properly. Thank you @JohnDanielsCPA for the advice, I used a city water hookup to get all the air out of the water lines before we departed, and the pump worked great all weekend, though I did have an issue when the fresh tank fell into the 30% range. 

After using the shower the second day and the Fresh Tank showed 30%, the pump would run endlessly without shutting off. I was turning the pump on and off manually at that point to build some pressure for the sink only when needed. Shortly after this, the water pressure started sputtering with air indicating we were abut to run out of water. Weirdly when it finally lost most of its water pressure the fresh reading still read 28% full..... 

I had learned from the previous owner that when the water tank is around 30% or less full, the pump has trouble building full pressure and continues to run endlessly, so I knew to turn it off manually at this point. However I was definitely a bit perplexed as to why the tank was seemingly empty with the reading at 28%...

dragonsdofly

Most of us with the seelevel guages get to know the idiosyncrasies of our individual trailers. Our fresh tank is dry when the guage indicates 25%. Our black reads 17% when empty but the gray reads 0 when empty. Because we know this we can pretty accurately predict when we're actually full or empty. Our fresh water tank reads 100% when full, so when the guage reads 65/60 we're at half. You'll just have to approximate according to your readings. Good luck and happy t@bbing!

danp212

Ok so i've heard back from nuCamp directly and they believe I need to loosen the water pump "bypass adjustment screw" about 1/2 turn CCW. Their belief is the bypass is maxing out before the switch is shutting off the pump. Adjusting the bypass switch CCW will trigger it to shutoff the pump earlier with less pressure built up, and should solve my high pressure issue. I have the water tank drained right now since we wont be taking the trailer out for another 6 weeks, so I wont be able to fully test this adjustment until mid-December when I refill the tank prepping for our next trip, but I will definitely report back with my results then. 

Sharon_is_SAM

Oh, that's a new one.  Where is the screw located?

danp212

Its on the bottom of the pump (the way mine is mounted in the bathroom), here is a picture of the bypass & pressure adjustment screws locations:

 

dsatwork

@danp212 The reason for an inaccurate reading is because the only position for mounting the sensor leaves it hanging off of the edge of the fresh water tank. This picture shows how mine came from the factory and the comments are from the factory, noting what the correct position should be.

Sharon_is_SAM

dsatwork - were you able to refit that sensor?  If so, how is the accuracy?  Is that the Alde in the distance?

dsatwork

SAM said:

dsatwork - were you able to refit that sensor?  If so, how is the accuracy?  Is that the Alde in the distance?

Although I was temped to do this fix myself, I let my dealer do the work for me. NuCamp paid for and sent out a new sensor and Eric at Little Guy San Diego did the install. He has has done very little work on Tabs, so he gained experience and did a great job too. (of course I checked his work) What you see in the distance, is where the propane line that goes to the Alde is connected at the frame via a brass distribution connector. I found this problem when I was doing the high altitude Alde fix. Still not very accurate, even when it's properly positioned, it still hangs off the edge. I wish sealevel would develop a smaller sensor that could be mounted straight up and down on small tanks. These are the issues you have to accept when you buy a Tab. It's my position that NuCamp is trying to put so much into these tiny trailers and sometimes the industry just doesn't have the necessary parts for it to work optimally.

Sharon_is_SAM

Thanks dsatwork.  We are going to have the high altitude Alde fix done on our clamshell at the end of November.  I wonder if nuCamp will access the same area or just go under the driver side bench.  I would like to know where our sensor is located on the fresh water tank.  Also, can you tell from your picture where the fresh water outlet is located on the tank?  Thanks in advance!

dsatwork

@sam you can't see the fresh water outlet from that pic, but it's easy to find. Just kneel down in front of the step and look to the left of it. Very easy to see. Also, they will be inside protective cover at the back of the trailer, because that is where the propane valve is mounted for the Alde high altitude fix.

Sharon_is_SAM

I meant the outlet leading to the pump, not the fresh water drain.  Is the drain an extension of the fresh water outlet or is there another point of exit for the tank?  

ScottG

On mine the FW tank drain is teed off the line that also runs to the pump. It's pretty obvious as the 2015's didn't have the fancy underpants of later models.

dsatwork

SAM said:

I meant the outlet leading to the pump, not the fresh water drain.  Is the drain an extension of the fresh water outlet or is there another point of exit for the tank?  

I think I saw it when I had the front portion of the undercarriage cover removed during upgrades.

Sharon_is_SAM

Thanks.  I wondered if there was more than one "outlet" of the tank.