Water pump (one more time)

[David Brady]

Just got off the phone with Shurflo. Apparently there is
an adjustment screw on the pump to adjust the internal
pump pressure regulator. I'll give it a try. Otherwise,
I may try a replacement pump. The behaviour is that the
pump ramps up too rapidly, overshoots, and ramps again.

David B
'02 LXi, Smokey
NC

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@...
>
> > >> '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
> > >>>
> > >>
> > >>
> > >> ----------------------------------------------------------
> > >> ---
> > >>
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> > >> 5/1/2007 2:10 AM
> > >>
> > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> >
> >
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> 5/1/2007 2:10 AM
> >
>
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>
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