What water pressure pump setting?

[cwf]

Howdy..
We have a Shurflo fresh water pump.. it is the second (as far as we know) for our 1999.

We have never had 'good' water flow when running on the FW pump. The accumulator tank seems to do fine as the pump will build up pressure, then shut off. If we turn off the pump, we can have water flow until the accumulator fully exhausts.

The FW pump also 'hammers' pretty good...and takes a while to 'pump up' to pressure and shut off..

I can buy a 'standard' 4008 or 4048 which is higher volume with increased pressure shut off.

Here is the location of the PDF for the 4048:
http://www.shurflo.com/images/files/...s/911-1024.pdf

There are adjustments for pressure bypass but stock runs until about 30PSI at which time the BYPASS kicks in. Bypass from outlet back to inlet can be adjusted. The PRESSURE switch is set to 55PSI.. of course if you have the bypass pressure set lower than the PRESSURE switch, the pump will not cycle/shut off.

According to manufacturer, the BYPASS eliminates the need for an accumulator... but I do not plan to remove or shut off our accumulator.

So, my questions....
- is 55-65 PSI too much pressure for our systems?
- is there a problem mounting the pump to our stiff plastic lines? Will they be damaged? The Shurflo document above says specifically "Use exible high-pressure hose on the pump inlet and outlet [such as SHURFLO Kit 94-591-01]. The pumps ports and strainer should not be connected to plastic or rigid pipe, or the pump's normal motion will transmit through rigid plumbing causing noise, and possibly loosening or cracking components."
- is there a problem with the higher volume delivery? (wasting water when boon docking?) Seems we could set our water taps for lower flow when appropriate.. and higher when needed, it is available..

Ok.. fire for effect...

[ROBERT CROSS]

Our household pressure is 55psi, it's not been a problem when hooked to the AS.

POI...not even sure what the pump pressure is....but after springing a leak in the middle of the night, , it's now a 'total' demand system, no accumulator and the pump is off until needed, especially when sleeping or vacant.

Bob

[mayco]

I installed the 4008 last summer hoping for higher pressure and flow. I have been pretty disappointed in it. Ive followed the manufacturers instructions for adjustment to no avail. One thing to note, which I didnt realize until after I purchased the pump, is that it is recommended for minimum 1/2" pipe. My 310 motorhome has the original piping and it is 3/8". Not sure if thats really a big factor or not. I dont have an accumulator. I timed the water volume per minute at the kitchen sink and at the shower (without the shower head) and got just over a gallon per minute of flow. Not very scientific but that seems awfully low. I have a very straight forward set up with no mods to the FW system. Ive checked all the obvious possibilities for restriction, like the strainer and such.

It gets good reviews overall but Im not real happy with it.

Mike

[cwf]

Mayco... Thanks for that info!!!

Let me offer another 'test' for pipe size affect.. you can get the items necessary at a local plumbing supply (not like a big box store).. then connect a shorter hose, larger diameter (like 1/2") to the pump outlet and run into a bucket/milk jug. Have someone run the 'pump switch' for you... until it meets about 30 seconds.. then measure... and multiply for a minute's flow...Also, good to run it into a bucket before quickly switching to the measuring container.... without shutting off the pump.. this will minimize the 'accumulator' effect.

How does it compare?

We are NOT getting the 2.8 gallons from our current pump either, more like one (1) .. City water provides a much better flow rate.

Perhaps a 'demand' pump as Bob has installed may provide a better solution. The part I like about the 'accumulator' is that the pump can run until pressure is built in the system allowing 'short/burst' use without a pump startup... Also, softens 'water hammer' when shutting off the water flow...

Bob, do you see those issues of instant on.off with the 'on demand' pump?

The on demand certainly has my interest..

[ROBERT CROSS]

The 'OEM' demand pump has not been a problem at all, no banging, and it flows very well. I have not tested volume or pressure.

My bathroom leak was caused by a cross threaded PEX connection that gave out at 5am....if it wasn't for the 'noisy' pump we would have had 50gal on the bathroom floor....lesson learned, pump is OFF 'til needed.

Bob

[mayco]

Bob, do you know what model pump you have?

CWF, thats a good idea on the test. At least it could tell me if the smaller pipe size is having much affect on the flow rate.

Mike

[Ag&Au]

The times we have had hammering in our plumbing, it has been caused by air in the pipes, Opening each faucet till it no longer sputters (a few seconds usually) has always alleviated it. It is almost always the galley faucet that has the sputtering. Our noise is exaggerated by pipes that touch the cabinet frame and bang against it with the hammering.

Our stock pump has served us well.

Ken

[Wanderer2604]

Our pump was tied directly to the stiff PEX water lines but I put in a short section of flexible tube to isolate the pump noise from the plumbing.

[ROBERT CROSS]

Originally Posted by mayco

Bob, do you know what model pump you have?

CWF, thats a good idea on the test. At least it could tell me if the smaller pipe size is having much affect on the flow rate.

Mike

Mike,

Aquajet ES 3.5 GPM (not at the faucet @ the pump outlet, still that seems like a LOT)

Bob

[mayco]

Thanks Bob.

[Jammer]

Originally Posted by cwf

We have never had 'good' water flow when running on the FW pump. The accumulator tank seems to do fine as the pump will build up pressure, then shut off. If we turn off the pump, we can have water flow until the accumulator fully exhausts.

The FW pump also 'hammers' pretty good...and takes a while to 'pump up' to pressure and shut off..

I've never had the pump work as well as I would like in either of our rigs. They are an adequate technology, not a perfect one. I have a variable speed pump in my 2010 Airstream, which tends to "hunt" for the right speed and cycle on and off, and a fixed speed pump in my Cayo, which cycles on and off the way most of them do. Neither of my rigs has an accumulator.

I can buy a 'standard' 4008 or 4048 which is higher volume with increased pressure shut off.

Here is the location of the PDF for the 4048:
http://www.shurflo.com/images/files/...s/911-1024.pdf

There are adjustments for pressure bypass but stock runs until about 30PSI at which time the BYPASS kicks in. Bypass from outlet back to inlet can be adjusted. The PRESSURE switch is set to 55PSI.. of course if you have the bypass pressure set lower than the PRESSURE switch, the pump will not cycle/shut off.

While I don't have experience with that particular pump (I think they're relatively new on the market), the PDF makes it sound like a good choice.

According to manufacturer, the BYPASS eliminates the need for an accumulator... but I do not plan to remove or shut off our accumulator.

::shrug:: Most modern RVs don't have an accumulator, but I don't think it will do any harm.

So, my questions....
- is 55-65 PSI too much pressure for our systems?

Anything up to 60 PSI is common. If the new pump smokes out a problem, it's probably one that you had before but that the pressure made worse. I would watch for leaks at first, and repair them if necessary, and call it good.

- is there a problem mounting the pump to our stiff plastic lines? Will they be damaged? The Shurflo document above says specifically "Use exible high-pressure hose on the pump inlet and outlet [such as SHURFLO Kit 94-591-01]. The pumps ports and strainer should not be connected to plastic or rigid pipe, or the pump's normal motion will transmit through rigid plumbing causing noise, and possibly loosening or cracking components."

Yes.

Use a flexible hose, ideally rubber or something else fairly elastic, on the outlet. Several feet is ideal, and you can coil it up to keep it out of the way. On the inlet you still need something flexible to allow for some movement of the pump, but the pressure changes aren't as pronounced, so it isn't as big of a deal.

- is there a problem with the higher volume delivery? (wasting water when boon docking?) Seems we could set our water taps for lower flow when appropriate.. and higher when needed, it is available..

No real problem there. You can add an inline valve to your shower head if you need one.

[cwf]

Thanks all! Great advice!!

[J. Morgan]

Ok,,,,

I used toilet supply hoses for both the inlet and outlet of my pump, it made my pump all but silent.

My trailer is plumbed with 1/2" pex throughout, my pump makes better volume than some park supplies. I run it at whatever pressure it was built at, I am guessing around thirty.

A run of 3/8" tube will restrict flow quite a bit more than 1/2".

The longer the run and the greater the number of turns the more restriction. Higher pressure will compensate for the smaller diameter tube to a degree.

The pressure is often over 100 psi where I park my trailer.... It is still cool.


Brevi tempore!

[David Logue]

Okay guys, my particular system in the 25' 2008 Safari SE has a Clear fine wire mesh filter located in line next to the pump.
After sitting for months the filter builds up a black type mold. The filter itself unscrews from the pipe. I take it and clean it out with a tooth brush and a little bleach and hot water.
just put it back in and pressurize the pipes......Fixed just like new

[cwf]

This is just a bit off thread... But I would be concerned. My money is on a load of lower quality water...

I have left our AS for a few months and there was no issue with the screen doing that. I would recommend NOT using that water until you solve the reason the screen is doing that.

Perhaps the screen is defective...does the contaminated screen have any odor to it? If so, I would nuke the water tank, drain, repeat. Then rum a load of fresh thru the tank...
Have you been trained on treating the fresh water system??? Not trying to bring discontent... Just trying to understand where u are coming from...

For instance, where do you get the fresh water? How? Filled with Garden hose or dedicated water hose? Does water hose have a filter??? Have you filled tank with water at a park dump staion? How long does the water sit (stagnate) between uses? Have you owned since new???

I run a dose of "non scented Clorox" from m the tank, thru the system...'if your sink aerators slow down, some goop has been removed from m the tubing... Could be biological or non organic...(calcium, iron, etc)

Hope it gets resolved...Soon!