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Re: Update to Water Pump Issues and New Question

March 06, 2016, 09:35:55 am

Thanks again, everyone, for the info submitted previously.  I'm creating a new thread because our problems are continuing, despite REPLACING the pump.  I searched the Forum for Shurflo 5.7 and 4048 before posting what follows, but didn't find anything recent.  Point me in the right direction if I missed something?  Here's the current chronology:

• Found the breaker in the basement bay and reset. The pump worked a few days. Our Feb 19 post was written in the glow of that success.
• A new stage of the problem emerged when the water pump light would stay on, but the pump wouldn't work. That immediately preceded our cross-country trip.  So, we carried 4 gallon-sized jugs of water for flushing the toilet and bought a lot of bottled water to drink.
• We tried finding a direct replacement (Shurflo 5900, 5.7) but no luck. So, we purchased a 4048 that said on the box it was the direct replacement for the 4900/5900. Had it installed. Voila — water. Hooray!
• The replacement pump, or its installation, is not working satisfactorily.  It "burps," whereas the 5900 made a wonderful, continuous whirring sound. Water just flowed.  The 4048 also seems to alternately provide hot and cold water, rather than mixing the two, whether to the sinks or to the shower.  And it makes the lights above the kitchen sink flicker.  The only water appliance that seems to work like the old pump is the toilet, which fills with a continuous whir (although a much louder one).

Certainly we can try one more installation and go back to the accumulator tank.  But do you think we should have had better results with this "direct replacement" (volume/flow aside)?  We also purchased a Flojet V-Flo constant pressure pump 5.0 gpm — but the installation would have been more difficult, not as close to a direct swap, so we had the Shurflo installed.

Thoughts?  Thanks always, for how great this Forum and all of you are.


Richard & Susan

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Re: Update to Water Pump Issues and New Question

Reply #1 – March 06, 2016, 11:41:18 am

@Richard,

The Shurflo pumps are adjustable. I'd try doing that since it's super easy. Attached is an screen grab that shows how. Grabbed from The Lazy Daze Companion: Adjusting The Shurflo Revolution 4008 Water Pump

I was able to bring mine under control by just increasing the pressure adjustment. Hopefully that will work for you. I would do that before doing the full adjustment described in the pic.

Not sure why you are getting the light flicker. Must be an electrical issue but I'd try the pump adjustment first then go after the flicker.

Good luck.

see ya
ken

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Re: Re: Update to Water Pump Issues and New Question

Reply #2 – March 06, 2016, 12:07:28 pm

The light comes on when the power to the pump relay is energized (from kitchen, bathroom, utility bay). Does it flicker in the bathroom?  If it is flickering and the lights in the kitchen are filckering then it might be a ground wire issue.  Hard to chase down but make sure your ground wire at the pump is secure.  Many of those ground circiuts go back to the box at the foot of the bed where they go to a common point which is grounded to the chassis.

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Re: Update to Water Pump Issues and New Question

Reply #3 – March 06, 2016, 12:55:49 pm

Shurflo 4048 is probably the best water pump, and certainly one of the most popular.  The 4048 has none of the Shurflo 5.7 problems and is a very good replacement for the 5.7, which has been discontinued for many years.

Years ago water pumps used to be simple devices that were either on or off which worked ok for high water flows, but low water flows created big pulses as pump rapidly turned off and on.  Accumulator tanks were standard on higher end RVs to help reduce rapid pulsation.

Shurflo 5.7 was an attempt to create a variable speed pump that would run slower when only low water flows were needed.  It used an electronic circuit board (in the base) to create the variable motor power, which proved to be a complex problematic design.

Shurflo 4048 (& 4008) uses a simple internal adjustable bypass valve that allows the constant speed motor to pump water not flowing out a low-flow faucet back to the input side of the pump.

Aqua Hot creates water too hot for bathing, so it incorporates an adjustable mixing valve which adds cold water to lower the hot water temp.  Also shower valves have an internal balancing valve that senses pressure changes.

Since the water pump only moves cold water, hot - cold cycles would have to be caused by something downstream, that is overly responding (or responding too slow) to the 4048 water pump cycling.  Certainly an accumulator, even the small plastic Shurflo accumulator that we installed in our motorhome could help with pump cycles.  But a problematic Aqua Hot mixing valve may be the main cause of the hot - cold feeling.

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Re: Update to Water Pump Issues and New Question

Reply #4 – March 07, 2016, 12:24:04 am

Another possibility is that the AH takes more distance and therefore more restriction when the pump pressure is low the water is colder and when the pressure is higher you get more hot water added to the mix. I ran into this issue on my Monaco AH when the pump cycled without the accumulator.

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