How To Troubleshoot An RV Water Pump Pressure Switch

rv water pump pressure switch

The water pump is one of the most important component in your recreational vehicle (RV) as it is a must that water is always available. The good news is that RV water pumping systems are not hard to repair, provided they have not suffered any damage due to overuse or extensive wear and tear. You can start with simple RV water pump pressure switch troubleshooting and avoid having to call out an expensive repair man.

What is the RV water pump pressure switch?

The water pump pressure switch is often located on or near the water pump itself. It controls the power flow from the house batteries to the water pump and tells it when to turn off based on a set PSI, typically 35 PSI.

The switch will come with two wires that connect to your 12v house batteries, which can be found in your battery compartment. The wires connect directly to one side of your battery bank and are usually black and red. They also feature male ends, which can be connected to wire terminals.

The other end of the switch features a threaded connection for the PVC pipe that runs from your clean water tank and connects it to your city water inlet hose. The PVC pipe has a diameter of either 3/8” or ½” depending on whether you have an older or newer model RV.

Signs your pressure switch needs to be replaced.

When you're troubleshooting, consider these signs that your pressure switch needs to be replaced:

  • Faulty water pump: If your RV water pump is faulty, it will have problems turning on and off. This may cause the pressure switch to malfunction as well. If you suspect your water pump is the problem, it's best to replace both parts at the same time.
  • Water heater issues: A lack of hot water in your RV may point to a faulty pressure switch. When this happens, the heating element doesn't get enough power, so it isn't able to heat up the water in the tank.
  • Frequent cycling: If your pressure switch is working but not properly regulating the amount of electricity sent to your RV's electrical components (like lights and appliances), then you may notice frequent cycling. This means that they turn on and off rapidly without warning.
  • There are several signs that your system may need a new pressure switch. First, you will want to check for leaks coming from around the base of the switch. Leaks can be an indication of a bad seal or faulty gasket.
  • If you notice signs of rust or corrosion on the switch it's likely time for a replacement. A rust-covered switch indicates that moisture has gotten inside the housing.
  • If you suddenly have a quiet rv water pump, there might be a problem.
  • If your RV water pump turns on and off rapidly, (a condition known as cycling), this could indicate a faulty pressure switch. If this is happening it's time to replace it with one of our direct fit replacements.

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Pressure Switch Adjustment (Including how to adjust a Shurflo pressure switch)

The majority of RV water pump switches have a preset on and off range. To adjust them, unscrew the big nut in the middle of the switch and you will see there are small nuts inside of it. Turn the small nuts to adjust the on and off PSI. If the switch is turning on at 35PSI and going off at 50PSI, turn the adjustment nuts in a clockwise direction until water pump shuts off at 45PSI or higher. Turn both adjustment nuts counter-clockwise until you reach desired PSI for your pump. Do not turn these adjustment nuts more than 1/4 turn at a time!

Replacing The Pressure Switch

If adjusting the pressure switch didn't help, then you may need to replace it. This is more complex than adjusting the switch, but it's still not too hard. All you have to do is buy a new pressure switch and install it on your RV.

Cleaning The Pressure Switch

The first place to check when you have low water pressure, or no water pressure at all, is the filter. If you have one of those filters, take it apart and clean it thoroughly.

If that doesn't fix your problem, there's probably something wrong with your pressure switch. The first thing to do is remove the cover and look inside. You can use a small brush or toothbrush to clean out any debris that may be in there. If there's any rust or corrosion in there, you'll need to replace the switch.

The best way to clean your pressure switch is by removing it from the pump and needle-valve assembly. You can do so by following the steps below.
  1. Remove the pressure switch from the pump housing.
  2. Inspect the inside of your pressure switch for any dirt or debris that may be blocking the button or plunger.
  3. Clean all the dirt and debris from your pressure system with a brush and vacuum cleaner or compressed air.
  4. Once your pressure switch is cleaned, you can reassemble it on the pump housing.
  5. Checking The Water Line

    The first place to check if your water isn't running properly or the pressure isn't right is the water line. If you have a frozen or blocked water line, then this can cause your pressure to be off or for there not to be any water at all

    How Do I Know If I Need To Replace The RV Water Pump Switch?

    The water pump pressure switch is a critical component in the operation of your RV's water system. Most RVs have a 12-volt water pump that is activated when you turn on the tap. The pump pressurizes the water tank to supply water to your faucets, toilet, and shower.

    There are several reasons why you may need to replace the switch. The most common one is that it malfunctions or breaks, which can cause serious damage to your rig if left unattended.

    • To test your water pump pressure switch, turn off the water heater and open all the taps in the RV. Then start the water pump and listen for any changes in sound.
    • If there is a change in sound when you open a faucet, but no water comes out of it, then you'll know that the pressure switch has failed and needs to be replaced.
    • You can also test the wiring of your system by turning on the water heater and opening all taps as before. If there is no change in sound when you open each faucet individually, then the switch may have failed or been damaged by dampness.
    Here's the bottom line: If you don't do routine maintenance on your water pump, it will break down.

    If you live or travel in an RV for any length of time, you'll run into problems with your water pump. It simply isn't a matter of if, but when. The good news is that the majority of the time, that problem is nothing more than a little dirty water system sediment that has collected in the pressure switch.

    The pressure switch is the component that tells your water pump to pressurize and depressurize your RV plumbing system as needed. A small amount of sediment builds up over time and interferes with the operation of this device. The result? Low water pressure, inconsistent water pressure or no water at all.

    Fortunately there's a quick and easy fix for this problem! With just a few tools on hand and about 20-30 minutes you can get that water flowing again and get on with enjoying the great outdoors.

    Frequently Asked Questions

    Step 1: Turn off the pump.

    Step 2: Hold the tube that is attached to the switch with your thumb.

    Step 3: Turn on the pump and see if water comes out of the tube.

    Step 1: Locate the pressure switch.

    Step 2: Set the pressure level to a higher pressure than what is currently set.

    Step 3: Turn the power off to the water pump.

    Step 4: Wait for at least five minutes and then turn the power back on to the water pump.

    Most often, the failure of an RV water pump is due to a power supply issue. Here are some common reasons why your RV water pump may not be turning on and what you can do about them:

    Problems with the electrical system

    If there’s a problem with the electrical system of your RV, it will likely affect all systems that require power to operate. If your RV water pump is not turning on and you’re confident that it’s receiving a steady flow of water from the tank, check the electrical system for any issues.

    A blown fuse

    A blown fuse may be what’s causing your RV water pump not to turn on. It’s relatively easy to check for this issue if you have any experience working with wiring systems.

    Is the Water Pump Stuck in the On Position?

    At times, a water pump can get stuck in the on position. This will cause your water pump to run all the time, even when you're not using any water. This can also cause it to overheat, which will prevent it from turning back on until it cools down. So if you've just recently turned off your RV water pump and turned on your faucet and nothing happens, try waiting a few minutes before trying again. If it comes back on, then this indicates that the water pump was stuck in the "on" position and overheated. In this case, you might want to consider replacing your RV water pump because if it overheats once, chances are it wi

    Is Water Pushing Back Through Your Fresh Water Tank?

    If you're experiencing low pressure at your faucets but the RV water pump is running continuously, this could indicate that there is an obstruction or blockage somewhere in the line between your fresh water tank.

    Conclusion

    Pressure switches are supposed to be relatively maintenance-free, but they do fail on occasion. The first thing you should do if your pressure switch isn't working is check for an air lock in the water line. An air lock prevents water from getting to the pressure switch and triggering it. The most common cause of an air lock is a change in elevation. If you've recently moved your RV from a low altitude to high altitude, there's a good chance you have an air lock problem. Moving from high altitude to low altitude can also cause this issue.

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