Water Pump Replacement

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Bob Buchanan

Well-known member
Mar 3, 2005
Philadelphia, PA
My water pump began leaking around the main gasket, so rather than doing one of those repair kit things, decided to replace it. I did a great job of in the install except for one problem -- it does not work? :(. If I turn off shore water and turn on a faucet anywhere -- it does not turn on.

The pump is a Surflo 2088-422-444, 2.8gpm, 7amp, 45psi. The problem appears to be that I'm not getting AC power. The red and black that was connected and worked with the old pump does not register voltage. However, I see that the source of these wires does not go in the direction of the fuse box, but rather in the opposite direction.

So my question is, does the pump somehow only receive power when the demand is there (unhooking from shore)? I was of the impression that it always received power and switching on and off was a function of the demand pressure in the housing. I have checked all the fuses in the panel and they are OK. I did a mail order on this and it arrived w/o instructions.

Another question: When on shore water, is that water going thru the pump -- and is that how it knows that that pressure is no longer there? It's hard to tell from the hose set up going thru the floor and round about the pump. The leak was happening whether or not I was hooked up.

And still another question: Should I have to prime this puppy? It states on the box that it is self-priming.

I would start checking at the switch inside that turns the pump on.  I believe the pressure switch is in the pump and the two wires, Black goes to ground and the red goes to the on/off switch inside if you have only one on/off switch.  How many places inside are water pump switches located? The pump is normally operated by battery power not AC.

The pump should run even if it isn't primed but normally they will prime themselves. You should have 12V DC at the red lead of the pump. Black should be ground. As Ron said, you normally have a switch that must be on to make the pump work. Measure between the leads to see if you have the correct voltage. If not check your fuse which should be labled in the fuse panel.

Hello Jim and Ron:

>> If not check your fuse which should be labled in the fuse panel.
It turned out to be a fuse. I had checked all the fuses up front and they all looked OK. I then downloaded a PDF file from Shurflo that mentioned their pumps should be fused separately -- not thru the fuse panel. Looking at the in-line fuses I found in the battery compartment there didn't seem to be any blown. How do you tell if one of those"white" material like fuses is blown?

Anyway, I decided to change "all" the fuses in my rig :). I read somewhere that that was a good idea periodically -- and it worked. I ran the pump for about 10 minutes and there didn't seem to be any leaks. This model has a flexible rubber base - and it's mounted on carpet in my Tioga. Am pleased with how quiet it is.

A little sidle here to lurkers -- check the in-line filter to your water pump every 6 monts to a year. I had never thought of that and when I finally cleaned it when replacing the pump found quite a bit of junk in there. That could have put extra pressure on the pump housing and may have led to the gasket failure. FWIW.

Thanks again Jim and Ron.
Glade to hear you got the pump fixed.

The only way to tell if those ceramic or white fuses that you cannot see the fuse link are good or not is with a ohm meter or they work or don't work in a circuit.
Hi Bob,

Glad you found the problem. Forgot some pumps have in-line fuses.  Good point on the filter. It's there to collect junk and it does. :)
Jim and Ron:

I am one of those RVers that never questions how something works until it breaks  :). So tho I now see pretty well how this Shurflo works, I can't figure out what the line is coming off the intake side of the pump. Is that the fresh water from the post that also goes through the pump? Will try to post a pic to show what I am asking.

At first, I thought this was the scenario: The line coming across from the right bottom I assumed is the freshwater from the post. To the left is the water tank with a line coming into the pump. On this side, you can also see the plastic filter casing. The fresh water moving right to left enters the pump "outlet" side via the perpendicular line off of the main line. That pressure coming in from the outlet side keeps the pump pressure switch closed while water is entering from the post.

When that flow stops from the post, the pressure backing off releases the pressure switch turning the pump on. It in turn moves water from the water tank back down the line that the fresh water was coming from.

The other scenario: My problem with scenario  one is that I am having trouble figuring what the line is for coming off of the intake side of the pump between the filter and the water tank. Note that it wraps around the upper side of the pump -- then goes down through the floor. I thought it might be a drain, I can't find the other end of it. So then, I figured it might be the "input" from the post -- and it goes straight thru the pump -- keeping the switch closed while the pressure is high enough. If the pressure drops, the pump turns on and brings water from the water tank instead. The problem here is that if the water is on from the post, it would also back up into the water tank. I don't see a check valve there.

So I lean toward scenario one -- and don't have a clue as to what the line is for between the water tank and the inlet side of the pump.

The other pic is of the old pump. Thought you might be interested in how extensive the gasket leak was. I see those are guaranteed for two years -- and that one has been there since '98.

The other item of interest here is the location of the pump. Fleetwood put if under the bed - along with most of the electric stuff. To get to it, one has to remove the mattress and unscrew the plywood covering. A real chore.


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From your picture I would guess the fresh water feed comes in on the output side of the pump. The input side going through the floor should be the tank drain. I would crawl under there and see if there isn't a petcock or capped line stickiing through the floor. It could be hidden by a frame member or insulation. On all the coaches I have seen the fresh water feed from the post joins the output of the pump. You should be able to follow one of the lines to the outside fitting.


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