Pulsing water flow fix

rfuss928

The very short water lines in the DM T@Bs cause the water flow to pulse with every beat of the pump.  This is most evident at low, water conserving flow rates used while dry camping.  I don't know if this is an issue with the much longer plumbing runs in the newer models.

Several years ago I discovered a small accumulator that substantially reduces the pulsing and pump cycling.  It is an easy install in the pump outlet plumbing.

Clearly not a necessary change but a nice improvement for you tinkerers looking for a small off season project.

Have Fun!

Bob

ScottG

Nice solution. I notice a bit of pulsing in my 2015. In happens primarily with the cold water. I wonder if the longer run of the HW lines and Alde HW tank act as an accumulator of sorts.

It looks like there's a regular Schrader valve on the base of the accumulator. What pressure do you pump it to for best results?

rfuss928

ScottG

I'm sure the larger volume systems have more compliance giving some what of an accumulator effect with any trapped air just helping.  The first photo shows virtually 100% of the plumbing in my T@B - not much room for dampening effects.   With the accumulator the pump only runs in short bursts every 5 or 10 seconds at low flows.  Before,  the best that could achieved was a sort of spurting with slower beating of the pump.  The system is also noticeably quieter.

The accumulator pressure needs to be set at the cut-in pressure of the pump so the volume of water stored is just depleted as the pump comes back on.  IIRC The  charge pressure ended up at ~30psi and the resulting working volume is about 4 oz.  This is essentially a very miniaturized version of a typical domestic well water system.

This is kind of an esoteric improvement that would be most appreciated by those obsessed with details.  There seem to be a few of us here.....

Have fun!

Bob

YanniLazarus

This product was just mentioned in a thread about leaking water pipes. Any installation experience with newer T@Bs?  I have a 2020 320 and almost exclusively boondock. If so,  where did you install it? 

Denny16

Yanni, if you look at the installation photos above, you will see rfuss installed it next to his water pump.  This is the best location, keeping the plumbing connections short. 

Cheers 

YanniLazarus

Denny16 said:

Yanni, if you look at the installation photos above, you will see rfuss installed it next to his water pump.  This is the best location, keeping the plumbing connections short. 

Cheers 

Yes... unfortunately that won't work for me... I've already moved my pump to the side to fit in a camco winterizing bypass valve, so no more room in there. I'm considering the cold water line under the sink.  I haven't looked that hard yet, but would have to convince myself i wasn't losing the storage space I won by installing that hypvo(?) vent replacement thingy!

Denny16

Yes, you could mount the accumulator tank under the galley sink.  It is not that big, and can be mounted to the cabinet bulkhead up high in the back, which typically is not used much.  The tank can be installed at any point in the do,d water line between the pump and faucet tap.
 Cheers 

kottum

I've installed these in our previous trailers to take up thermal expansion of the closed water system and therefore prevent leaks at fittings and the pressure release valve, and also to smooth the flow of water throughout the plumbing system.

An extra measure I took different than the picture above was to install the accumulator on its side or with the lines at the bottom so it would self-drain or could be blown out with air when winterizing.  In the position shown above, some water may remain in the accumulator and freeze.  I'm not sure it would be enough to crack the device, after all it is a pressure accumulator.

Doug K

YanniLazarus

Thanks... and now the big question- is it worth the effort? What do you think? 

Denny16

Yes, I think so, and I plan to install one in our TaB this spring before we go out camping again.  Using an accumulator tank reduces the water pump cycles, and saves energy, as well as keeping a more even water pressure.  As Doug (Kottum) mentioned, it also protects the TaB’s plumbing against pressure surges, even when connected to city water, preventing leaks.
Cheers

kottum

It is absolutely worth there effort if it helps prevent leaks from thermal expansion and smoothes the water system flow.  There will also be less recycling of the pump for small water draws because it keeps some water in the little reservoir, under pressure.

I have often wondered how many small leaks trailers have from thermal expansion in the water system that owners never know about, as they are in the crooks and crannies where never seen.  Out of sight, out of mind I suppose.

Doug  K

YanniLazarus

Well, I needed another project for right now. Still waiting for the really slow shipping of the parts needed to do AnoldUR's outdoor shower mod, so i'm going to order that tank right now.

YanniLazarus

Easy-ish installation. I took the lower end hose coupling for the 320S sink cold water feed and attached it to one side of the accumulator, and added a 1 foot hose on the other side of the accumulator to reconnect to the coupling in the lower cabinet. This has made a really significant improvement in pump noise and water flow smoothness. Thanks for the suggestion. Oh- used a bike pump to put in 30 pounds of pressure. 

Denny16

Nice job,  and you didn’t loose any real storage space.

Cheers 

MarkAl

Adding one of these looks like a good idea. My questions are mostly related to winterizing:
- I assume it's best to mount the in/out connections are the lowest point to allow draining.
- We use air pressure to clear the lines, any issue with this technique?
- What's an easy method to use for determining the pressure setting for the tank? I assume at the pump outlet pressure setting.

After examining the area by the pump, I'm thinking the best plan is to remount the pump and move the lines around. Sadly, the inlet is on the wrong side of the pump and the filter would be better 90 degrees to where it's at. It would make installing the tank much easier.

YanniLazarus

MarkAl said:

Adding one of these looks like a good idea. My questions are mostly related to winterizing:
- I assume it's best to mount the in/out connections are the lowest point to allow draining.
- We use air pressure to clear the lines, any issue with this technique?
- What's an easy method to use for determining the pressure setting for the tank? I assume at the pump outlet pressure setting.

After examining the area by the pump, I'm thinking the best plan is to remount the pump and move the lines around. Sadly, the inlet is on the wrong side of the pump and the filter would be better 90 degrees to where it's at. It would make installing the tank much easier.

first, yes I do think this is a good thing.  And winterizing is definitely a good question! 

I do not use air pressure to clear lines -- I installed a camco winterizing valve in the water line just before my pump -- which required repositioning my pump to make room.  I think we live in different universes -- the configuration of your 2021 must be different than my 2020, with your nautilus (you have one, right?)

With my self-installed winterizing valve reducing the amount of antifreeze I need to about 1 gallon, I just like knowing for sure that there is no residual freezable water in the system... but, to each his own.  In any event, there was no room for the pressure tank adjacent to my pump, so I mounted it under the sink, with no intention of draining it.  I might let the pressure out during "the winter" but we tend to use our T@B year round, so I likely won't bother.  

You can either "T" to the tank and connect to one side, or run your water through the tank.  I opted to run my water through the tank so that when I winterize I'm assured to have antifreeze in the tank, and don't have to figure a way out to drain it.  I was only interested in adding the tank if it didn't overly complicate my life... I need to make sure I have plenty of time to wash and wax my baby!

Apparently our factory-installed pumps are set to go on at 30psi.  I didn't obsess over this, and just used a good quality hand pump to put 30 pounds of pressure in prior to installation.  Seems to work just fine.  There is a simple schrader valve on the pump, making it easy.  I'd just make sure you can get to the valve end when you mount yours.

Denny16

Once the water pressure is nil, the accumulator tank will drain into the water lines, and out the low point drain.  Even if a small bit of water remains and freezes, no damage will occur, as water has a room to expand in side the tank.
 Cheers 

rfuss928

It's a surprise that this modification didn't seem to generate any interest for ~4 years.  The accumulator made a big difference in our T@B.  The lack of response made me assume it wasn't an issue in the newer T@Bs.  These recent posts seem to indicate there is a noticeable improvement even in the larger water systems.
Good to see the idea being used...
Have fun...
Bob

MarkAl

@Denny16 so you're saying that as long as some space empties of water there will be enough room for expansion in the tank when it freezes. Okay I guess I can accept that. I'd still prefer to mount it with the inlet and outlets at the lowest point.  But it will be a lot easier to mount on its side.

Denny16

That is correct, the 30psi bladder in the tank wii force out most, if not all the water, once the water line pressure is less than the tanks pressure.
 Cheers