Water pump (one more time)
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05-01-2007, 13:38
Post: #17
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Water pump (one more time)
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 > > 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 > > > >>> > > > >> > > > >> > > > >> ---------------------------------------------------------- > > > >> --- > > > >> > > > >> 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] > > > > > > > > > > > > > > > > > > > > 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] > > > > > ------------------------------------------------------------------------ > > 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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Messages In This Thread |
Water pump (one more time) - Keith Strehle - 05-01-2007, 04:35
Water pump (one more time) - Ralph L. Fullenwider - 05-01-2007, 04:51
Water pump (one more time) - Keith Strehle - 05-01-2007, 05:42
Water pump (one more time) - Ralph L. Fullenwider - 05-01-2007, 05:54
Water pump (one more time) - Pete Masterson - 05-01-2007, 07:37
Water pump (one more time) - Curt Sprenger - 05-01-2007, 07:41
Water pump (one more time) - David Brady - 05-01-2007, 07:50
Water pump (one more time) - Pete Masterson - 05-01-2007, 08:53
Water pump (one more time) - Pete Masterson - 05-01-2007, 09:04
Water pump (one more time) - David Brady - 05-01-2007, 09:19
Water pump (one more time) - David Brady - 05-01-2007, 09:33
Water pump (one more time) - Terry Neal - 05-01-2007, 09:49
Water pump (one more time) - Pete Masterson - 05-01-2007, 09:49
Water pump (one more time) - David Brady - 05-01-2007, 10:10
Water pump (one more time) - David Brady - 05-01-2007, 10:30
Water pump (one more time) - Gregory OConnor - 05-01-2007, 12:50
Water pump (one more time) - David Brady - 05-01-2007 13:38
Water pump (one more time) - ac7880 - 05-01-2007, 15:39
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