Mystery? What's your thoughts?

[DutchmenSport]

First, I never hook water up to the water hydrant and leave the water on, even if we are on a site that has full hook-up. I always fill my fresh water tank and use my on board water pump. I've been doing it this way for 20 years, and not changing. Beside, we camp at to many places that do not have water on site.

With that said, I use a 35 gallon water tank and a water transfer pump to pump water into the trailer fresh water tank. Also, I use a Barker Blue Tote to haul away waste as we camp a lot on sites that do not have a sewer connection on site. But, if we are on a full hook up site, I will connect to the sewer. (no need for the tote then).

OK, that's the background.

Now the mystery.

Every since I've owned this Montana, when first filling the fresh water tank, the water pump makes excessive noise. It really hammers. After a while, it gets quiet again and we can barely hear it. It really is very quiet.

Now, not moving the camper at all, still on the same site, I need to fill the tank again. Either with available water on site, or using my 35 gallon transfer tank, it doesn't matter .... after filling the fresh water tank on the camper, the water pump hammers again. It will eventually quiet down until it's really quiet again. Fill up, and it's noisy for a while. Run a few gallons over the next day, quiet again. Trailer never moves.

Anyone have any clue why it get's so noisy after filling?

I don't mind the noise, never did, but I do enjoy the pump a lot more when it's in "quiet mode" and not "noisy mode."

[432bartman]

Could it be air in the system?

[DutchmenSport]

Not sure how it could be air. I fill the fresh water tank before it's completely empty (35 gallons or less). So, no opportunity for the water pump to suck air from there.

When using my garden hose, I always fill the hose with water first. Even at the water fill station, I'll use the same hose from the hydrent to the tank. When the tank is full, I disconnect both ends of the hose and hook them together to keep the water in the hose. Then use the same hose to transfer from the tank to the trailer, with water still in the hose. I do this deliberately so I'm not loosing a half gallon of water just to fill the hose, and to keep air out of the hose and infused into the system. Besides, when pumping the water into the fresh water tank, any air would go into the trailer water tank and bubble to the top and out the tank vent. I don't see how air could be getting in the water lines.

I'm not sure what's going on at the water heater though. It's said there is an air pocket on the top of the water heater tank?

FYI, the pump does not run unless the ice maker is filling or we are running water from the toilet or faucets. I don't think there are any leaks anywhere in the line, otherwise, we'd hear the water pump run after loosing about 2 ounces of water. We do not have an Actuator tank in the system either, and no filtration system.

Still, anything is possible? I'm wide open to anything, or even the impossible?

[jdarwin]

DutchmanSport, could it be the pump is not screwed in tight enough? As the pump runs the vibration causes it to settle? I know my old pump was loud in one part of the rig and almost completely quite in another part. Just guessing.

[Daryles]

Ours does the exact same thing. I have installed ALL the "water pump noise" fixes and when the pump is running (after I get the air out of the system) you can barely hear it.
Now after we move (road traveling) you can hear it hammer (known as water hammer).
The best way I have found to fix it is to run the shower cold water tap full blast until the air is out (stops sputtering). Takes about 30 seconds. I run it into the toilet bowl so it's not wasted.

[mlh]

It’s a caveating. It’s picked up some air. When it gets rid of the air it quiltings down.
Lynwood

[rames14]

As mlh said, it’s cavitation. It gets air when you are switching between fill and flow. Now, if you can figure out how to eliminate it, there are a lot of us that want to know.

[mlh]

It’s nothing to worry about, forget it.
Air is much lighter than water therefore much easier to pump. When your pump tries to pump air you get a little hammering noise.
Lynwood

[DutchmenSport]

Thank-you all. I did not know this about air and cavitation. Had to look up that word "cavitation", never heard it before until now.

So, it sounds like (maybe), the water pump impeller is somehow causing air bubbles in the water line, thus the hammering. Once the bubbles work out, the hammering goes away.

That makes absolute logical sense and I can buy that. But there is still the problem, how does the air get there to begin with. As ramis14 pointed out, when switching from flow to fill could introduce the air. This does makes sense too.

Well, as far as I'm concerned, this is a pretty good logical explanation of what is happening, and I find it interesting that I'm not the only one who experiences this. So, this must be pretty normal.

As I said earlier, the noise doesn't bother us, we've accepted it as part of the camper's little quirks. But after 3 years of ownership, I figured it was about time to figure out why it does this.

Thanks again everyone. You've been most helpful once again!

[rohrmann]

These pumps do not use impellers. They are diaphragm pumps so no impellers.

[BB_TX]

Originally Posted by rohrmann

These pumps do not use impellers. They are diaphragm pumps so no impellers.

Right. They use pistons rather than impellers.


If you wanted to get industrious you could replace the old pump with a jet pump.

https://rvnerds.com/2018/02/11/tired...ump-heres-fix/

[rohrmann]

Originally Posted by BB_TX

Right. They use pistons rather than impellers.


If you wanted to get industrious you could replace the old pump with a jet pump.

https://rvnerds.com/2018/02/11/tired...ump-heres-fix/

Actually, the operation of these pumps more closely is like your heart, chambers squeezing and valves to keep the fluid moving in one direction. There aren’t any pistons either.

[BB_TX]

Not pistons as in an internal combustion engine. But pistons (or plungers) actuated by solenoids to move the diaphragms back and forth.

[wed]

I bet it’s air you get in it when you feel the tank. The loud noise is the pump filling the line and pushing the air out

[phillyg]

You're correct, its a mystery, to me, too. If its very bothersome, perhaps you can install a water hammer device.

[bcrvman]

Originally Posted by DutchmenSport

First, I never hook water up to the water hydrant and leave the water on, even if we are on a site that has full hook-up. I always fill my fresh water tank and use my on board water pump. I've been doing it this way for 20 years, and not changing. Beside, we camp at to many places that do not have water on site.

With that said, I use a 35 gallon water tank and a water transfer pump to pump water into the trailer fresh water tank. Also, I use a Barker Blue Tote to haul away waste as we camp a lot on sites that do not have a sewer connection on site. But, if we are on a full hook up site, I will connect to the sewer. (no need for the tote then).

OK, that's the background.

Now the mystery.

Every since I've owned this Montana, when first filling the fresh water tank, the water pump makes excessive noise. It really hammers. After a while, it gets quiet again and we can barely hear it. It really is very quiet.

Now, not moving the camper at all, still on the same site, I need to fill the tank again. Either with available water on site, or using my 35 gallon transfer tank, it doesn't matter .... after filling the fresh water tank on the camper, the water pump hammers again. It will eventually quiet down until it's really quiet again. Fill up, and it's noisy for a while. Run a few gallons over the next day, quiet again. Trailer never moves.

Anyone have any clue why it get's so noisy after filling?

I don't mind the noise, never did, but I do enjoy the pump a lot more when it's in "quiet mode" and not "noisy mode."

Probably some air in the system, install a water hammer or make your own.

[StageCoachDriver]

I keep a small amount of water in my freshwater tank to flush the toilet when traveling. Other than that, I use park water.

[Gubs]

As you fill your fresh water tank are you releasing pressure with the value located toward the end of your unit on the drivers side? Might just be building up to much pressure with might cause your problem. Just a thought!