One of the issues that make DIY wiring a challenge is the different components that need to be used. For example, if you wire in a Sea Level monitor, you can’t use the on/off switch. You need a momentary switch to work with the monoplex relay.
There are a lot of wiring diagrams for the RV water pump switch. The one you may need may not be the one that is posted here. To get the right wiring diagram, look up your make and model of RV and see what comes up. The wiring can be tricky.
To see a few wiring diagrams, just continue to read our article. The ones posted here are generic diagrams to give you an idea of where to look. The wiring is not complicated, just finding the wires and route may be a challenge.
The following diagram may be for one 2020 RV model. There is no specific label to this diagram.
Knowing some terminology and their abbreviations will help you understand what the technician is talking about when you consult them for your water pump problems. Here are a few terms to be aware of:
- Gallons per minute- GPM- this is the rate of water that flows through your water system. It is rated by how many gallons pass a certain point in one minute
- Pounds per square inch- PSI- RV water pumps are designed to only handle water pressure between this range- 40 to 60 PSI. Avoid any water pump that is rated higher than 60.
- Amperage- Amps- the amount of electricity the water pump will need to work properly. Normally, water pumps do not draw a lot of electricity but there are some models that need up to 15 Amps to work.
This diagram will be of a Shurflo water pump system.
The following diagram is for the Shurfalo RV but for which specific model is unknown. This should give you a great idea of how things work and their routes.
Not all RV water pumps are the same. The only aspect they have in common overall RV models and brands will be that they all should work with 12 volts. There may be exceptions to this rule.
There are some that are rated for 110 or 120 volts but they usually have different purposes than the standard RV 12-volt water pump. Besides this difference as well as the brand names and specs, there are 3 basic types of RV water pumps. Their names are self-explanatory:
1. Constant speed- the most common unit found in RVs. These units are either on or they are off.
2. Variable speed- can create water pressure similar to your traditional home’s water pressure. There is a built-in water pressure sensor that adjusts the pump motor’s speed. The good news about this model is that they tend to be quieter. The bad news is they cost more.
3. High volume- has to have a flow rate of 4 GPM or higher to be considered high volume. These units are found in 50-amp RVs usually and require more electricity to run.
1. The water pump works but no water flow
The first place to check would be your fresh water tank. If it is empty the water pump may turn on but no water will pass through the system. The second place to check if there is water in the tank is to look at the pipes and connections. There could be leaks, plugs, to other problems stopping the water.
Finally, the water pump may be failing and only sounds like it is working when in fact it needs to be repaired or replaced.
2. The water pump won’t work after winterizing it
In the spring when you are getting your RV ready to roll, you may experience this problem. But there are a few common sense issues that may cause this problem.
The first will be, did you close the drain to the fresh water tank? If not, then you may have been watering your driveway and not filling your tank. Second, did you reconnect everything once you go the antifreeze out of the system?
Check everything twice and make sure all valves that need to be closed are closed. Third, is their power getting to the pump? A fuse may have blown when you started everything up and that is a common problem.
Finally, the fuse is fine but there is still no electricity getting to the pump. Use your multi or volt meter to check your power supply to the pump.
3. Water pump cycles with the faucets off
This is generally a sign of a leak somewhere in your system. The water pump will not know the difference between an open faucet and a leak. It just knows when the water pressure starts going lower, it needs to turn on and pump more water. Look for leaks and seal them up.
4. The water pump is noisy- the water pump may not have been installed correctly and was loose direct from the factory. Just tighten the bolts or add some rubber padding between the water pump and the frame, etc., to soften the noise level.
Getting the right wiring diagram for your RV is essential if you are doing your own electrical work. In most cases, but not all, the RV brands may furnish you with a diagram if you contact them directly.
Some brands won’t because the wiring for each RV model is different even though they are in the same model series. Often, some owners have to draw their own diagrams to make sure they know where all the wires are going in their RV.
That option is simple for smaller RVs but more complicated for larger ones.