Water pump (one more time)

[David Brady]

Could be. The pump seems to behave a lot better when the
water level goes down. In fact a tank that's half full puts the
head pressure at zero psi cause the water pump is bolted to
a one and a half foot high platform. (Pump is at the same height
as the water level). I did a quick calculation, a 2 ft high column
of water only generates 1 psi, but this may be enough to overwhelm
the sensitivity of the pumps pressure sensor. There may be
something to what you're saying: "the pressure control is effected
by the loss in psi on the discharge side". I'd like to remedy this
by altering the sensitivity of the pressure sensor; i.e, make it
less sensitive. I'm away from the coach so tinkering will have to
wait. Shurflo tech support seems to be clued in to this issue. The
new pumps have a pressures sensitivity adjustment. They said,
"turn on a faucet and turn the adjusting screw clockwise until
the pressure oscillations stop". At least they added the adjustment
ability.

Thanks for the suggestion,
David B
'02 LXi, Smokey
NC

Gregory OConnor wrote:
>
> David, I wonder if head pressure is the cause of the fluctuating hot
> water issue. Because after 1/2 the tank of fresh water is up, the
> problem stops.?????????? If the tank outlet to the pump is on the
> bottom of the potable tank?????? the hot water tank is pressurized by
> cold fresh water via the pump and it may flow in too fast and the
> pressure control is effected by the loss in psi on discharge side
> with the higher then able gpm flow. If there is a valve on the inlet
> to the Hot water tank you can try and close it some to restrict gpm
> flow and psi loss. or just pinch it with a vice ( if soft
> tubing)??????????
>
> GregoryO'Connor
> 94ptRomolandCa
>
> --- In WanderlodgeForum@yahoogroups.com
> , David Brady
> wrote:
> >
> > I called Shurflo and they specified that the pump should have
> > at least 18 inches of elbow free tubing both at the inlet and
> > at the outlet. I have much more than that. I don't use any strainer
> > at all. All tank water is filtered as the tank is filled, so I'm
> > thinking that the strainer isn't necessary. With the original dual
> > fuel pumps both used strainers, and the strainers were always
> > spotless. To quiet the pump even further I mounted it using a
> > Jabsco vibration pad kit, part number 43990-0058. These legs
> > provide much more vibration dampening than the original
> > Shurflo legs. The pump is virtually silent. I do have aquahot.
> > What I experience, especially on hot water, is: as the hot water
> > is turned on, the pump ramps up, stops, ramps up again, stops,
> > and again. It may do this half a dozen times before it settles down.
> > In the shower, this turns in to variation in temperature. Since the
> > cold water pressure is fairly constant, the cold water flow stays
> > the same, but the hot water oscillates. The temperature varies from
> > say 115 deg F to 120 deg F every second or so. Very annoying.
> > But then, after say half the fresh water tank is used up, everything
> > works properly. Maybe another call to Shurflo is in order.
> >
> > David B
> > '02 LXi, Smokey
> > NC
> >
> > Pete Masterson wrote:
> > >
> > > Reading the installation instructions with the pump, it cautioned
> > > about isolating it from vibration to the plumbing. My coach has
> the
> > > gray plastic pipe (polybutyl -- that's no longer used as it was
> the
> > > subject of class-action lawsuits in the late 90s due to unexpected
> > > failures in homes and manufactured homes). I purchased "Flare-It"
> > > fittings from PEX Connection along with a few feet of 3/4 inch
> I.D.
> > > PEX tubing. PEX can be bent around corners so long as it has a
> > > suitable bending circumference (which is a chore to accomplish in
> the
> > > space available for the pump). So, from the end of the original
> > > plumbing, I have a 3' section of PEX looped to turn 90 degrees to
> > > enter the pump, which is mounted on one of the (apparently) wooden
> > > boards attached to a metal bulkhead where one of the original dual
> > > pumps was located. Again, on the outside, I have another similar
> 3'
> > > section of PEX with a large loop to connect to the outbound
> original
> > > plumbing. This effectively isolates the pump from transmitting
> > > vibrations through the plumbing system. The PEX tubing is
> (somewhat)
> > > flexible and the dual curves allow
> vibration/expansion/contraction as
> > > necessary.
> > >
> > > The higher pressure did not cause any unexpected problems with the
> > > existing plumbing -- except the main fresh water drain valve
> started
> > > leaking from a long-existing crack in the plastic valve body. (I
> > > could see that it had been present for some time due to the dirt/
> > > corrosion present.) I then replaced the drain valve and associated
> > > fittings with brass or white plastic as appropriate.
> > >
> > > The pump doesn't vibrate the plumbing but it isn't
> exactly "silent."
> > > The mounting, even with rubber 'feet', etc. still vibrates the
> > > bulkhead it's attached to, so you can hear the pump when it is
> > > running -- but it's not particularly intrusive and you don't hear
> it
> > > over the "whoosh" of the shower, for example.
> > >
> > > I note, too, that I started having a problem with the Microphor
> > > toilet flushing. It does not "like" water pressure above 50 psi
> and
> > > doesn't flush properly at the 65 psi from the water pump. I've
> > > learned to open a water faucet valve on the bathroom sink, then
> flush
> > > the toilet in the fraction of a second before the pump kicks on --
> > > temporarily solving the Microphor problem until I can install a
> > > pressure limiter on the water line that serves the toilet.
> > >
> > > All-in-all, I'm very satisfied with the 6.7 gpm 65 psi variable
> speed
> > > pump. It has eliminated the two original pumps (that were both
> > > leaking) and the complexity of the related plumbing along with the
> > > accumulator (expansion) tank. (Another source of plumbing woes if
> the
> > > diaphragm leaks or it becomes de-pressurized.)
> > >
> > > I'm also enthusiastic about PEX tubing (pipe replacement) and the
> > > Flare-It fittings. While special clamped fittings are often used
> with
> > > PEX (requiring a special clamping tool), the Flare-It fittings
> don't
> > > require any special tools, but a simple wrench-thing they sell
> makes
> > > tightening them a breeze (I used a channel-lock plier, but their
> tool
> > > would probably not leave tool marks like the pliers).
> > >
> > > In retrospect, about the only thing I might have done differently
> is
> > > to use 1/2 inch I.D. PEX tubing. It would have been much easier to
> > > bend into the loop shapes in the area I had available -- still, I
> was
> > > successful with the 3/4 inch tubing and it does not restrict the
> > > water flow.
> > >
> > > I do not get "pulsating" very often ... but sometimes, when the
> > > bathroom or kitchen sink faucet is turned on, I see just a little
> bit
> > > of it -- but it goes away in a moment after the pump fully comes
> up
> > > to speed. I've never noticed it with the shower but, perhaps, the
> > > flow limiter in the shower head allows the pump to 'catch up'
> before
> > > any pulsating begins.
> > >
> > > The water is heated in an AquaHot system -- this is a tankless hot
> > > water system, so there shouldn't be any air pockets (as in a hot
> > > water heater) on a newer coach. (I assume you have an AquaHot.)
> > >
> > > Did you install the high-capacity water filter? I note that the
> > > variable speed pump requires a high-flow filter. It was about
> twice
> > > the size as the water filters used with the old pumps in my coach.
> > >
> > > Rather than an air pocket, there simply may be a restriction
> > > somewhere in the lines into or out of the pump, causing it to be
> > > unable to fully come up to pressure as fast as it should, when a
> > > valve is opened.
> > >
> > > Pete Masterson
> > > '95 Blue Bird Wanderlodge WBDA 42
> > > aeonix1@...
> > > On the road at Lockhart Texas
> > >
> > > On May 1, 2007, at 2:50 PM, David Brady wrote:
> > >
> > > > I also have the Shurflo Smart Sensor 5.7 65psi pump. My inlet
> > > > and outlet plumbing are long lengths of 3/4" ID tubing. The
> > > > connections to the pump are the Extreme Series Straight
> > > > fitting 3/4" quick connects, part number 94-615-04. These
> > > > fittings eliminate any elbows at both the inlet and
> > > > outlet of the pump. The trouble is, I still get pulsating and
> > > > hunting while the pump tries to zero in on the pressure and flow
> > > > required. Anyone else have this problem? It's worse on the
> > > > hot water than on the cold. I suspect an air pocket somewhere,
> > > > probably in my hot water heater. It gets better with time, but
> > > > by then, my fresh water tank is close to empty, it's time to
> fill
> > > > up, and the pulsating starts again. Again, I'm thinking an air
> > > > pocket.
> > > >
> > > > David Brady
> > > > '02 LXi, Smokey
> > > > NC
> > > >
> > > > Pete Masterson wrote:
> > > >>
> > > >> THe original pump in my coach provided 40-45 lbs pressure. I
> > > >> installed a ShurFlo variable speed pump that provides 65 lbs
> > > >> pressure. The coach plumbing seems to be 'up' for this
> although I
> > > >> have an anomaly with the Microphor toilet (it doesn't like
> pressure
> > > >> above 50#). Mostly, the higher pressure gives you a
> better "user
> > > >> experience" when you take a shower. The variable speed pump
> also
> > > >> eliminates the need for the accumulator (expansion) tank.
> > > >>
> > > >> Pete Masterson
> > > >> aeonix1@... > 40mac.com>
> > > >> '95 Blue Bird Wanderlodge WBDA 42'
> > > >> El Sobrante, CA
> > > >>
> > > >> On May 1, 2007, at 11:35 AM, Keith Strehle wrote:
> > > >>
> > > >>> I am going to replace my water pump this weekend. There are
> ShurFlo
> > > >>> pumps available on the shelf for about $70. The pump is
> supposed to
> > > >>> put out 45 psi but I've heard many people here talk about the
> 65 psi
> > > >>> pumps. 65 psi seems a little much. Is 65 psi necessary and
> how much
> > > >>> does the original pump put out?
> > > >>>
> > > >>> Thanks, Keith
> > > >>> 84FC35
> > > >>>
> > > >>
> > > >>
> > > >> ----------------------------------------------------------
> > > >> ---
> > > >>
> > > >> No virus found in this incoming message.
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> > > >> Version: 7.5.467 / Virus Database: 269.6.2/782 - Release Date:
> > > >> 5/1/2007 2:10 AM
> > > >>
> > > >
> > > >
> > > >
> > > > [Non-text portions of this message have been removed]
> > > >
> > > >
> > > >
> > > >
> > > > Yahoo! Groups Links
> > > >
> > > >
> > > >
> > >
> > >
> > > ----------------------------------------------------------
> ------
> > >
> > > No virus found in this incoming message.
> > > Checked by AVG Free Edition.
> > > Version: 7.5.467 / Virus Database: 269.6.2/782 - Release Date:
> 5/1/2007 2:10 AM
> > >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>
> ------------------------------------------------------------------------
>
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