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Old 10-03-2016, 01:07 PM   #1
3 Rivet Member
2012 25' FB Flying Cloud
Parker , Colorado
Join Date: Aug 2015
Posts: 130
New Water Pump Won't Pressurize

My SHURflo 4900 - 0201 was making way too much noise and not delivering a steady stream, so I replaced it with a SHURflo 4008-101-E65. Can't get it to fully pressurize when off of city water, it just runs and runs. Really strange part is everytime I open a faucet it's spitting air and water no matter how long I run it, and then when I close it the hot water heater sounds as it its refilling. Even when the sound stops, the pump stays on. Every faucet runs hot water only no matter if I have it turned to cold or hot.

Here are the steps I took:

1. Once I replaced the pump, I hooked up city water and purged all the air from each faucet (kitchen sink, bathroom sink, toilet, shower, and outside shower.
2. Opened the hot water pressure relief valve until water comes out. I've also tried leaving this valve closed when the tank is refilling.
3. Disconnected the city water
4. With a full fresh water tank, turn the pump on and opening faucets one at a time.
5. I have an Accumulator installed under the sink. New pump says no Accumulator necessary. Could this be part of the problem? There is a shutoff valve for it, tried closing it and only using other faucets, but didn't help.

Is this pump powerful enough or did I get the wrong model?
With air spitting everytime I open a faucet, is this letting the hot water tank pressure push the contents back into the rest of the system?

I'm at a loss. Thanks for your help.
2012 25FB with solar
2012 Toyota Tundra 5.7L V8
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Old 10-03-2016, 02:04 PM   #2
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1991 34' Excella
Princeton , New Jersey
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If you have filled the hot water tank and have water in the fresh water tank the pump should pick up a prime in a few seconds. Air will be forced out of the faucet while this is happening.

The accumulator should have a minimal effect in the overall time. There is no back flowing involved.

if the system does not charge as described I would look for something open beyond the faucet you are using or the pump can not prime. Pump not priming with a new pump is most likely because it is sucking air. Check your connection on the input side of the pump.
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Old 10-03-2016, 02:08 PM   #3
3 Rivet Member
2012 25' FB Flying Cloud
Parker , Colorado
Join Date: Aug 2015
Posts: 130
OK, looks like I figured it out myself. Hopefully this will help someone else.

The water line between the fresh water tank and the pump has a couple of connectors in line, so I took it apart. There is a screen filter just before the pump, that was clean. I used a turkey baster and forced air through all of the parts. Then I put it into the section that goes down into the tank, and squeezed it in and out of bunch of times until some water was sucked into it. Put it back together and whoa Nelly, it works!

There must have been something in there. Now hopefully I didn't just push it down into the tank and it ends up coming back up....
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Old 10-03-2016, 02:53 PM   #4
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2014 20' Flying Cloud
Long Island , New York
Join Date: Jun 2015
Posts: 14,404
Even one small air leak between the water tank and the pump will defeat the pump priming itself FWIW. Sounds like you have solved this with the re-assembly.

Also -- the water heater tank is supposed to have a head of air trapped inside at the top. If you bled all the air out with an open pressure relief valve, you should restore the air head by draining the water heater tank part way (by removing the bottom drain plug). Re-install the drain plug, turn the water on (city or pump), and then run a hot faucet until no more air comes out.

This trapped head of air prevents the water pressure from getting too high as you heat up the water, similar to your accumulator. It is also a good idea to open a hot faucet briefly a few times, while you are heating a new tank of cold water, to relieve pressure, especially if you are using both the electric and propane at the same time.

Should be good to go.
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Old 10-08-2016, 03:06 PM   #5
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LAFAYETTE , Colorado
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This forum gave me a tip once to take the shower head off the shower that exits the side of the trailer for rinsing feet from the beach. Then suck on the end while partner inside turns faucet on. Presto, air lock purged
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