How To Diagnose Water Pump Problems Before Repairing Or Replacing RV Water Pumps

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shurflo-water-pump.jpgOkay, you've filled up the RV water tank and hit the switch to pump the last of the antifreeze out of the plumbing lines. 

The only problem is... the RV water pump just keeps running and won’t shut off.  The water flow is only a matter of a few drips at best. 

Now what?


How To Diagnose A Water Pump Problem

The first step is to eliminate the obvious. 

Are you absolutely sure there is a supply of water getting to the pump?  Silly things like "you left the drain open when you thought you were filling the tank" have fooled more then one person into thinking their RV water pumps were bad. 

If you disconnected the line from the tank to the water pump when you pumped RV antifreeze through the water lines last fall, has everything been reconnected correctly? 

Is there a shut-off valve you forgot to open?

If your pump never made any noise at all when you hit the switch, lack of electricity may be a concern.  Check the fuse in the 12-volt panel.  If it’s good, check for power at the fuse with a volt meter or a test light. 

Next check for power at the pump itself.  If 12 volts are present at the pump, one last check should be made before you declare the pump bad:  Check the ground for the pump motor.  If the pump isn’t  grounded, the presence of 12 volts will mean nothing.  It takes a good ground to make the circuit.

 

Replacing An RV Water Pump

Once you have determined that yes, indeed, there is a water pump problem:

1. Drain the fresh water tank. 

2. Disconnect the water lines.  (But have a couple of towels handy, as there will still be a bit of water in the lines that may run out.)

3. Disconnect the electrical connections. 

4. Unbolt the RV water pump from its mounting

5. Bring the water pump itself out to the work bench.

All of this sounds very easy, and in theory it is.  There may be one tiny problem:  If your RV water pump is mounted like the one in my travel trailer, you may have to be a 60 lb skinny-as-a-rail contortionist to physically reach all the connections required to remove the RV water pump.  There may be a removable access panel that will help you get at it, but most likely, it’s just going to be awkward and a bit of a pain.

 

How To Install A New RV Water Pump

There are 3 or 4 different brands of RV water pumps on the market. 

Some have rebuild kits available, though most would be considered throw away items.  With a wide selection of models available from $60 to about $150, it may be wise to just install a new pump and be done with it. 

Installing a new RV water pump is as simple as remounting the pump, and reinstalling the water lines. 

Be sure to use teflon tape on any pipe thread connections. 

Pay attention to arrows on the water pump housing indicating which port is the "in" or "out".  (They may be labeled as well.) 

Carefully read the instructions supplied with the new pump and you’ll be up and running in no time.

 

Why Do RV Water Pumps Fail?

For the most part, 12-volt electric water pumps have proven to be quite reliable and long lasting. 

The main reason for RV water pump failure (as with all RV water system components) is being left for the winter with water in the system.  Extensive periods of storage in hot summer weather down south may also shorten the life span of an RV water pump. 

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6 Comments

Robert Boyette said:

I am trying to winterize my travel trailer. I have always run a hose from the inlet side of the pump to the gallon of antifreeze, turned on the pump and pumped the antifreeze thru the lines with no issues. Today, the pump would not pull the antifreeze thru the lines. The pump is on but not pumbing. Wondering if I could have lost prime or if I have a bad pump. How would I re-prime the pump. Water hose won't fit..... and tried pouring water thru the 3/8" hose, but no luck.

Curtis said:

Russ, Your on the right track, the only other suggestion would be if your water tank is mounted at a higher level then the pump by hooking the pump back to the water tank and filling with water you will be flooding the pump assuring the best possible priming which will let you confirm if the pump is bad or not. I would think the pump should be able to suck the antifreeze out of the jug as most RV's have the water tank mounted underneath requiring the pumps to be self priming.

Bruce said:

Curtis,
I have a question, what would cause my system to spit air between spurts of water. It's not just the typical pulsation but it actually spits air/water when getting water from the fresh water tank. Any suggestions?

Curtis said:

Bruce, There are two possible problems. First, is there a filter of any kind on the inlet side. If it's plugged up you might get that reaction. Though the more likely cause would be a damaged diaphragm in the pump allowing air to get into it. I guess its a question of are you getting more water then air, or mostly air. If it's mostly air I think your pump may be going south.

Curtis said:

Hi Russ, If you want to pump antifreeze through the lines you will have to find the water pump and disconnect the waterline coming from the tank. Then place a hose from the antifreeze bottle to the pump and you can pump it through. Personally I've never used this method myself. I hook up a low pressure air line (5 psi)to the city water inlet and pressurize the system with air. Opening one faucet at a time until all the water is pumped out. I pour antifreeze down each drain, but I never put it in the water lines. I live in Northern Minnesota and over 30 years have never had a problem doing it this way and I've seen a lot of -20 degree weather.

Russ said:

Got a question about winterizing, I have a 1991 Terry Tauras and am wondering how I go about pumping antifreeze through the system. I am not sure where the water pump is and then how I would go about pumping antifreeze from the antifreeze bottle through the system. What we have done in the past was take my outside water line that ran to the trailer and put antifreeze in it and then pushed it through via an air compressor, this is very time consuming and I have heard that you can somehow just stick the water pump hose in the bottle and pump it through that way, but I am not sure how to do that. Any help would be appreciated.
Thanks
Russ

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