Why Your RV Water Pump Pulsates and How to Fix it – RV-N-Style

Why Your RV Water Pump Pulsates and How to Fix it

Shower spraying

Have you noticed that your RV water pump pulsates when you use it? I have, especially when taking a shower. Changes in water pressure and temperature while trying to shower in your RV is not fun.

Why does your RV water pump pulsate and how can you fix it?

Your RV water pump pulsates because it uses pressure switches to start and stop your water pump. If this switch is not set properly, pulsations occur. The more sensitive the pressure switch is to the change in pressure, the fewer pulsations.


Does fixing your RV water pump sound difficult?
It’s really not that hard. Since the pump operates on a difference in pressure, changing the sensitivity of the pressure switch can help control the cycling of the pump.


How To Fix Your Pulsating RV Water Pump

Making the switch more sensitive to the change in pressure caused by turning on the faucet, makes the pump start quicker and run longer. The water pressure stays steadier and reduces the frequency of pulsations. Most pumps have an ideal setting that can almost eliminate pulsations. When set correctly, the pump should remain on while you are taking a shower, and turn off when you turn off the shower valve.  Adjusting your pressure settings on most pumps is pretty easy.


Tips:

– You will need to have your shower running to make this adjustment.
– It can be helpful to have a second person monitoring the shower flow.
– Tools needed may be an Allen wrench (or hex-key wrench) or Phillip’s head (or crosshead) screwdriver depending on your brand of water pump. Both are easily found in any hardware store.


Find Your RV Water Pump

The first thing you will need to do is to find out where your RV water pump is located. The best place to start is in your wet bay.

RV Water Lines
Photo Credit Pentair

What Brand Is Your RV Water Pump?

The second thing you will need to do is to figure out which brand of water pump you have. Not all RV’s have the same brand of water pumps.

Once you have located your RV water pump and identified the brand (usually clearly identified on the pump or in your RV owner’s manual), you can follow simple steps to make the adjustments. 

Here are some examples of the most common RV water pumps and how to adjust them. Even if yours is not on this list, most have similar adjustments.

Adjusting Shurflo water pumps pressure setting

  1. Turn on your shower
  2. At the water pump, at the end of the water pump that the piping is connected to, you will find a housing that has 2 red wires coming out of it. On that housing find the hex-key adjustment screw (also known as an Allen screw)
  3. Using an Allen wrench, turn the screw clockwise until the cycling stops. Shurflo recommends one quarter turn increments. If you turn too far, the pump will not shut off even with the shower off. If this happens, just turn the screw slightly counterclockwise until the pump stops.

Adjusting a Flojet water pump pressure setting

  1. Turn on your shower
  2. At the water pump, using a Phillip’s head screwdriver remove the cover plate on the pressure switch
  3. Locate the Phillip’s head screw between the electrical connections under the cover
  4. Turn the screw clockwise to increase the cutoff pressure (to stop the cycling), if the pump fails to stop with the shower off turn the screw slightly counterclockwise until the pump stops.

Adjusting a Seaflo water pump pressure setting

  1. Turn on your shower
  2. At the water pump, at the end of the water pump that the piping is connected to, you will find a housing that has 2 red wires coming out of it. On that housing find the Allen screw adjustment screw (also known as a hex-key)
  3. Turn the pressure adjustment screw on the controller clockwise to stop cycling, if the pump fails to stop with the shower off turn the screw slightly counterclockwise until the pump stops.

These are examples of how you can adjust your current pump to help solve pulsation issues. Below are some alternatives to consider.

Upgrading My RV Water Pump

Variable Speed Pumps

Most RV manufacturers are starting to incorporate variable speed water pumps in their RV’s. These can be retrofitted to any RV and are a good solution for RV’s with pulsation problems.

Variable speed pumps use a pressure sensor on the outlet of the pump to monitor the operating pressure of the pump. A variable speed drive controller is then set to keep that pressure constant no matter what flow demands are placed on it.

This allows you to have one faucet or multiple faucets open without a change in water pressure.  The other benefit is that there are no pulsations due to pressure spikes. The pump simply slows down to maintain that pressure.

Most of the common pump manufacturers will have a variable speed pump line available. This includes Shurflo, Flojet, and Aquajet.

Pulsation Dampers

Another aspect of pulsation control is the pulsation damper. Pulsation dampers are accumulators installed into the water system at the outlet of the pump. They have a preset pressure charge on them that help to control pulsations, hammering, and smooth out vibrations.

Pulsation Dampers can be retrofitted to a system fairly easily. They can help with a system that is particularly prone to pulsations. There are some caveats to this.

Some pumps use an internal bypass to help control pulsations. Pulsation dampers should not be used with these systems.  Also, variable speed pumps are meant to be used without a pulsation damper. When retrofitting a variable speed pump, the old accumulator should be removed.

Programmable Pumping System

If you feel that you need the best of the best, there are some premium pumps available, of which Headhunter is one of the most popular.

Headhunter X-Calibur uses a variable speed centrifugal pump to give constant water flow at a given pressure and is fully programable based on your pressure and flow demands. These pumps are expensive but are the highest standard of water pumps.

These pumps utilize a built-in microprocessor that allows for the control of multiple pump factors. Headhunters Xcaliber for example, have these advanced features:

  • Adjustable cut-in pressure
  • Adjustable power setting
  • Operates on 12 or 24VDC
  • Overvoltage protection
  • Under-voltage protection
  • Overcurrent protection
  • Anti-flooding protection
  • Dry run protection
  • Variable Speed

All these features come at a cost though. The Headhunter X-Caliber sells for a surprisingly high price of approximately $1500.00. It might be worth it though for totally quiet, ultra-smooth, high-pressure water flow.

Related Questions

How Do I Prime My RV Water Pump?

  1. Make sure your fresh water tank is filled.
  2. Open your cold-water faucet.
  3. Switch on the water pump.
  4. This should prime your RV water pump.

Does My RV Water Pump Need To Be On When Connected To City Water?

No, you should not run your RV’s water pump when hooked up to city water. City water should bypass your RV water pump and provide plenty of water pressure. Your RV water pump is only designed to pull fresh water from your RV water tank.

Does Your RV Water Pump Run off of Your RV Battery?

Yes, RV water pumps typically are operated from your RV battery. They only draw power when actually providing water and are usually 12 or 24 volts.

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