Water pulses

[fmichaels]

Need some help or an old thread. Took trailer out of bypass today. Just installed accumulator to shurflo pump and charged to 45 psi. When I run the water from the tank, the flow continues to pulse for long periods. Once water is shutoff, the pump runs for about 10-15 seconds and then stops as expected. Faucet spits like there is air entrapped. If I run on city water, the flow is good after opening a few faucets and toilet. Then if I go back to the tank it chugs again. Does the tank level affect the flow. I didn't fill the tank to much. Thanks.

[Yamerhammer]

Try putting more water in the fresh water tank. It's easy to drain if thats no the problem.

[fmichaels]

Filled tank and flow was better but then started spitting again. Water pump kicks on about 5-10 seconds after faucet opened. Considering removing accumulator to see if that changes anything. We only had the trailer out two times last year, both on city water. This might have been a problem from the beginning. My old pop up worked better than this before and after I added accumulator.

[ckdixon]

There could be air trapped in the lines at one of the faucets. When turning on the pump, I always bleed the air from both the cold and the hot lines at each faucet starting at the one closest to the water pump. Don't forget the outside shower also if your RV is equipped with one.

[3'senough]

Originally Posted by fmichaels

Need some help or an old thread. Took trailer out of bypass today. Just installed accumulator to shurflo pump and charged to 45 psi. When I run the water from the tank, the flow continues to pulse for long periods. Once water is shutoff, the pump runs for about 10-15 seconds and then stops as expected. Faucet spits like there is air entrapped. If I run on city water, the flow is good after opening a few faucets and toilet. Then if I go back to the tank it chugs again. Does the tank level affect the flow. I didn't fill the tank to much. Thanks.

Did you pressurize the accumulator to 45 PSI? That should not be that high if so. They normally come pre-charged and it should be a lot lower than that at more like 20-25 where your pump kick on is set. If the accumulator cannot accept water it is not doing it's function which is to take 1-2 gallons of water and then feed the system that 12 gallons of water after the pump has kicked off.

If you did not set the psi to 45 then I would check for leaks somewhere.

[msturtz]

A few questions? Where did you install your accumulator and what size accumulator did you get? RV accumulators use a rubber diaphragm that separates the water from the air charge. Accumulators are supposed to be installed directly downstream from the pump. You need to set the accumulator pressure to exactly the same pressure is the pump turn on pressure in a static condition i.e. pump is turned off but at least one faucet is open. For example a 45 psi demand pump typically has a turn on pressure of 30 psi. In this case you would set the accumulator pressure to 30 PSI. If the pressure set too high in the accumulator capacity is reduced or potentially even eliminated because the accumulator would be at the same pressure as the plumbing lines are. This would mean that the accumulator essentially becomes worthless in this condition, however it can actually trap air creating other problems.

[fmichaels]

Ok, so I installed the accumulator just downstream of the pump. I did charge it to 45psi after reading the directions and realize now that was wrong. I will reduce the pressure down to about 30 psi tomorrow and see it that helps. I also didn't see any leaks. The accumulator was the model meant to be used with a Shurflo 4000 series pump. I have a 4008 model pump. The accumulator pre-charge was 39psi. Thanks for your help. I will report back tomorrow.

[Jmooney]

Ok, for those of us that don't know, what is a accumulator, and why do I want one?

[fmichaels]

An accumulator basically keeps the water system under pressure (when not using city hook-up) and helps your water pump cycle less (extends life). They also quiet down the system. There are a number of dry sites that we visit so I like to have an accumulator when running off the water tank.

[Jmooney]

Just sits in line with the pump?

powered, or just uses water pressure from the pump?

[fmichaels]

Yes, it's a pressurized tank that installs in-line with the pump. no power, only pressure. PSI can be changed through a bicycle (Schrader) valve located on the accumulator body. I installed one on my previous pop-up and they really work nice. Quieter system, less pump cycling, and smoother flow to the faucets. Again, this is when you are using your water tank and don't have a city hook-up.

[msturtz]

Originally Posted by Jmooney

Just sits in line with the pump?

powered, or just uses water pressure from the pump?

No the concept is simple. Accumulators have a rubber bladder that has an air charge on the other side that is set to the pump turn on pressure this means that the accumulator fills up with water on the water side which raises the pressure on the air side by reducing the volume that the air has to occupy. Air will compress but water will not. The benefit of an accumulator is you use the air pressure to run the coach water supply and the pump to keep pressure up in the accumulator. The same principle is at work by water towers. Pumps are used to fill the water tower but the pressure comes from the elevation of the tower. The larger the accumulator the smoother the water pressure in the coach. In my old TT I had a small accumulator installed however in my MH I have a 2 gallon large accumulator installed. It does make a huge difference.

[mcfarmall]

Accumulators are often used on industrial hydraulic systems where there is a high flow demand for a short period of time that exceeds the maximum GPM output of the pump. The first application that comes to mind is a die casting machine where the shot cylinder needs a lot of flow in order to move very quickly to shoot the metal into the die. The die open/close function doesn't need to be as fast so the pump flow can run it without the accumulator being in the circuit. The pump recharges the accumulator constantly.

Bladder accumulators are also used on home well water systems and operate on the same exact principle as an accumulator in an RV. Your well pump wouldn't last very long if it started every time you cracked a faucet.

I bought a small 1 gallon accumulator on line from Sears for around $20 and simply cut a tee into the cold water line under the bathroom vanity and suspended it from the underside of the vanity shelf...works great and the pump rarely cycles.

[3'senough]

Originally Posted by Jmooney

Ok, for those of us that don't know, what is a accumulator, and why do I want one?

AKA expansion tank. But must be an FDA approved bladder if you do residential. I have a 2 gallon for my unit.

[Grumpy]

Originally Posted by Jmooney

Just sits in line with the pump?

powered, or just uses water pressure from the pump?

Air on one side and then the pump/water pressurizes the other side.

[fmichaels]

We'll solved the problem. The inline filter cap was not tight and sucking in air. I also reduced the accumulator pressure to 30 PSI. Much better. Thanks for all your help.