Water System Accumulator Tank

Water systems in RV's are quite simple. There is a tank of water and a pump. Nothing else. This works quite well and is pretty reliable. However, water pumps make a fair amount of noise, not only the sound they make themselves, but also any vibration it transmits to anything it is connected too. Considering that the pump needs to run whenever a tap or toilet is used, the noise is always present whenever the need for water. Now don't get me wrong, it is not like a 747 landing, but it is enough to get minds like mine pondering a solution.

Pump manufacturers make these little devices called accumulator tanks, or pressure tanks. Anyone familiar with water systems tht run off a well or lake, know what I am referring to. The most common tanks are those blue ones made by Well-X-Trol. Basically they provide a pressurized source of water, so the pump does not have to run as often. On household system, these are generally in the 2-10 gallon range. The tank itself is split in two by a rubber membrane, one side is pressurized with air, the other is filled with water by the pump. The pressurzed air bladder applies pressure to the water in the other side, which in turn can then be fed out of a tap when needed. It fools the pressure switch on the pump itself, so that it does not come on until a low end threshold is reached. Works quite well, and the key to it all is the water capacity of the tank.

An RV water system works off the same principle, but without the tank, so the pump comes on every time water is needed. A little research revealed that there are small tanks available for RV's. I picked one up to install in the Alto. The tank I purchased is made by Shurflo, the brand of most RV pumps out there. The capacity of the tank is 24oz. Certainly not near the volume of household systems, but I figured it might be worth the effort. Found a good spot to mount it, got the correct PEX fittings, added a pressure gauge just for curiosity sake, and did the install in an afternoon.

Once I had everything sealed up again, I flipped on the pump. It immediately started to fill the tank, then stopped. Reading the pressure gauge, I fiddled with the upper pressure limit a bit to maximize the capacity of the little tank. No leaks, which is always a bonus.

Now for some testing. I was most curious just what was gained in terms of reducing the amount of time the pump ran and cycled during use. Running the kitchen tap at a reasonable rate of flow, the pump did not come on for at least 5 SECONDS! Then it ran for about 10 seconds to fill the little tank up again. Perhaps I overestimated the desired results, but I was hoping it would be of a little more value. I certainly overestimated the capacity of the tank. Although 24oz, in reality, it is probably only half that, considering the air membrane that sits in the middle. So 12oz really gets eaten up quickly. Factor in the amount of time the pump runs to refill the tank, compared to the delay in coming on, I suspect there is little or no benefit to be found in the installation of an accumulator tank of this size. It was an interesting mod though...


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