MOD Water pump upgrade with accumulator tank

[Neal]

So I have an issue now with water flowing in reverse out of the city water line when disconnected. Either I have something mounted in reverse or it's back pressure from the REMCO accumulator tank I just installed. I'm digging into the manual to see if maybe I have something incorrect with flow direction either on the new water pump or the accumulator and discovered this. Yeah, read the manual last right? However, I've had no issue with pressure to date so it appears to be working fine but this warning is concerning.

 

[BGMAC]

So I have an issue now with water flowing in reverse out of the city water line when disconnected. Either I have something mounted in reverse or it's back pressure from the REMCO accumulator tank I just installed. I'm digging into the manual to see if maybe I have something incorrect with flow direction either on the new water pump or the accumulator and discovered this. Yeah, read the manual last right? However, I've had no issue with pressure to date so it appears to be working fine but this warning is concerning.

View attachment 26895

It sounds like you are overcoming the check valve on the city water connection with to much pressure.

 

[Neal]

It sounds like you are overcoming the check valve on the city water connection with to much pressure.

Thanks. I was wondering if this was the accumulator tank causing back pressure vs. a line swapped. I could swear the lines are correct but I'd have to pull the wet bay panel off again which I really don't want to do. I can reach in to the shrader on the accumulator, I may try to discharge pressure on that and see what happens.

For anyone else running an accumulator, are you getting water out of the city water line when not connected?

 

[Neal]

Just had dinner and good thing I had some time to collect thoughts before ripping things apart. IF (all caps) I had lines reversed the water pump would not be working to draw water and send it up to the house. The water pump works fine, everything in the coach works fine water wise. What's causing the water to come out of the city water line and per my other thread seem like it's flowing backwards through the house filters is what I need to address. First I'll try reducing pressure in the accumulator, if that doesn't work I may have to remove it which would be painful but per REMCO an accumulator is not supposed to be used with a (their) variable speed pump. It is actually working great in the house doing what it's designed to do, it doesn't seem to be over pressured. I just need to figure out the backflow situation. Maybe installing a check valve would be an idea as well to prevent the water from flowing in reverse if I don't have one in place as is.

 

[osuallen]

Neal - I take issue with the "extreme" pressure statement. If the pump is set to shut off at say 65 psig, it will shutoff at 65 psig whether or not a bladder tank is installed or not. The timing of when 65 is reached is altered, but a correctly operating control will shut off at 65. Not sure where this "extreme" pressure statement comes from. The addition of a bladder tank will affect the system pressure profile as faucets/uses are turned on and off. The pump is variable speed, so it speeds up and slows down to maintain a given pressure as demands vary. The bladder tank alters the pressure profile, but should not normally negatively affect a pump.

As you probably know a bladder or accumulator tank has a rubber bladder in it. The water is on one side of the bladder and air on the other. As water fills the water side, the bladder expands into the air side and the air pressure rises as the air volume decreases (P1/P2=V1/V2) until the air pressure=water pressure=pump shutoff pressure. When a faucet opens the air pressure forces water out the faucet until the pressure drops below the pump activation pressure of the pump. Without a bladder tank, this pressure drop is nearly instantaneous as all the piping is near ridged (no expansion) (yeah PEX has some give so a few milli-seconds delay). After the faucet shuts off the pump will run a few extra seconds to build pressure back in the system to the pump shutoff pressure.

 

[Neal]

Thanks. I have a valterra check valve coming I'm going to put prior to the pump input line. I'll inspect tomorrow to see if I can figure out where the existing check valve is, if any. This should fix the issue to keep the water flow only going into the pump and not back from the accumulator pressure.

Amazon.com

 

[flyboy013]

@Neal - See this post and the ones following it. I had same issue this past summer. The check valve is behind the panel and up high. You can fill for it and change it without taking panel off. I also creating a flow diagram which may help.

 

[Kevin D Pem]

Thanks. I have a valterra check valve coming I'm going to put prior to the pump input line. I'll inspect tomorrow to see if I can figure out where the existing check valve is, if any. This should fix the issue to keep the water flow only going into the pump and not back from the accumulator pressure.

Amazon.com

Did your problem start after your freeze? If so a fragment from the filter may have caused your problem.

 

[Neal]

@Neal - See this post and the ones following it. I had same issue this past summer. The check valve is behind the panel and up high. You can fill for it and change it without taking panel off. I also creating a flow diagram which may help.

Thank you. I'll check for that today, either way inlining the valterra check valve in the visible portion of hose lower left of the wet bay panel prior to the pump should work as well. I see the next reply has the link to the replacement valve as well so I'll get one of those on the way. I'll try one of the two options, for now all works as long as the city water endpoint is capped off or connected to an open city water spigot.

 

[Joe Dutchstar]

The pump should have a check valve in it as once line pressure reaches the set value, the line pressure is maintained. Pressure is maintained until water is requested that reduces line pressure below set value.

 

[Joe Dutchstar]

Here is a review from Amazon. Note comments about mitigation of noise

These are pretty much the best performing pump you can get. They are also very high quality. The motor is heavy duty. They can also easily (and quickly) pump up to 120 PSI if you let them - they are that powerful. Fortunately, they come preset to 60 PSI max. Many complain about noise with this pump, that is not the pump itself, it's how you mount it and how the lines are routed to it. The recommended approach with these pumps is to put flexible hose to and from the pump. I did that but it made a horrible racket. It didn't matter how I repositioned it. So the other day I re-plumbed the suction and discharge side with 1/2" PEX. I changed the layout of the lines and now it's very quiet. If I put some insulation (rubber) under the pump it will probably be close to silent. Don't over tighten the mounting screws. Try it with them a bit loose to see how that affects the noise. This is one of the best pumps you can get, but you have to want to make it work. If that means fiddling with the mounting to make it quiet, so be it. Also, I've bought a few off Amazon and had to send them back because of shipping damage. For some reason, some models are just sent out the stock box put in a plastic bag. This one was shipped double-boxed (fortunately) and arrived safe and sound. I'm actually running this pump with a separate pressure switch (adjustable cut in and cut out) and also a variable speed controller for the pump. This way I have total control over the pump, with respect to volume and pressure. None of that is required, I just have a custom water system for high pressure and low flow to work with my on-demand water heater in my RV. You can just 'plug 'n play' this pump as it has conventional 1/2" RV fittings and it's own pressure switch. It also varies the pump speed using Pulse Width Modulation so it will increase speed or decrease speed as needed. It's really quite the pump. I highly recommend it if you need volume and pressure. You can run multiple faucets/showers/clothes washer all at the same time. Update: I relocated the pump later on, added a larger accumulator and needed longer lines. I chose not to hard plumb it with PEX this time and instead used stainless braided lines from Amazon. They were quite inexpensive and you get the benefit of rattle absorbing rubber lines encased in stainless braid. That worked out quite well and seems to be the quietest solution yet. Even so, I tie-strapped them so they weren't rubbing on anything. Not expensive to do and looks very cool. In the pic above you can see my custom solution. None of that is required, you can just use the pump as a stock replacement for yours right out of the box. I just wanted to do the pump justice and I do like my pressure high.

 

[Neal]

The pump should have a check valve in it as once line pressure reaches the set value, the line pressure is maintained. Pressure is maintained until water is requested that reduces line pressure below set value.

Yes, it's maintaining pressure which is causing the water to flow in reverse as well because the check valve apparently failed so water wants to flow back out the city water line.

As to the noise, it has good rubber grommets, my prior pump I put a rubber pad between the pump and the plastic faux wall Newmar mounts to. It's not really that bad, I just wish it was completely silent. I don't want to know when it's running. Then again, if I didn't know it was running I would not have caught the issue the other day with water flowing out the disconnected city water line. All is good, I just need to get a new check valve in line to prevent backflow. Easily mitigated for now.

 

[Joe Dutchstar]

Now I understand the issue. Thank you.

 

[Joe Dutchstar]

Here is a simple plumbing schematic for RV systems

 

[Neal]

Went to dump tanks and take a look for the check valve and fortunately it's right in front of my face. I also confirmed this city water line goes right into the right side of the house filter flowing right to left as I once thought.

I don't know the type of fitting used on this, in a quick Amazon search it seems it's some push connection. Not sure how easy it is to disconnect and replace. I think this item below is the replacement?

Amazon.com

I have this weird knack of ordering stuff before checking what I have! $150 of stuff coming from two places now and none of it will be used, fortunately most of it is returnable. Ugh...not the first time I've done this! My valterra coming today should work as well as the fittings but I may not have enough hose to bridge the gap. May have to reorient a few things.