PART #8 OF 8
ANTI-NOISE INSTALLATION TIPS CONTINUED
If frequent pump cycling or pulsing noise is problematic, a small, $30 to $60 accumulator tank can be added, but most installations won't require that, and most RVs don’t have them. These softball-sized tanks have a small air bladder inside that acts like a balloon, with both water and trapped air in the tank. The water won’t compress, but the air does, so with each pump pulse the trapped air briefly compresses, acting as a hydraulic shock absorber for the overall water system, reducing water hammer, noise and pump cycling. They can significantly help for problematic systems, a simple installation with two inlet/outlet nipples plus mounting feet. They make larger accumulator tanks as well, and due to their stored pressure they can even flow a little water without the pump running, so you can silently get a glass of water or flush the toilet at midnight without the pump cycling. A pump bypass valve is an internal spring-loaded diaphragm that opens up allowing water from the discharge side back to the inlet side of the pump, smoothing water flow and helping reduce cycling and pulsation. Both Shurflo and Flojet claim that pumps with bypass valves reduce or negate the need for an accumulator tank. The Lippert literature doesn't mention a bypass valve, but the Valterra, Shurflo and Flojet pumps all have bypass valves.
These eight posts cover mainstream constant speed pumps. More expensive variable speed water pumps (not covered here) are able to deal with water flow and pressure changes more smoothly, and negate the need/benefit of an accumulator tank.
Also check for pipes or hoses transmitting noise through contact against walls and such. Foam pads can be inserted in spots to reduce contact noise transmission. Pumps typically have pressure switch/bypass valve adjustment screws to reduce cycling, pulsing, and therefore noise, but the factory settings should work well for most people – read the manual. As for Teflon tape, I suspect the basic rule is to NOT use it since stray bits of tape can enter the pump or a water fixture and cause problems. But if a connector leak is persistent, then USE tape if you must to resolve. Some hose connectors have visible soft internal sealing gaskets, some have no gaskets (just smooth plastic mating against smooth plastic), both are common and workable. You might inspect your fittings’ mating surfaces for significant imperfections before installation, and gently try to correct if needed. Check for leaks after final installation, of course…some fittings are more equal than others. If mounted on a wall, the pump motor should face up so a potential pump leak doesn't flow from the pump module down into the motor (Shurflo #4008 can be mounted in any position). If you’re worried about freezing, the Lippert pump is rated to five freeze cycles, but I did not find any freezing references in other pumps’ literature or manuals. Pump documents commonly mention run-dry survivability should the tank empty, so that design feature appears more anticipated and common ("2 minute" run-dry protection in a Shurflo document from 2013, so perhaps that's a rough industry standard?). You might read through the entirety of a pump owner’s manual before buying, such as through a Google search of “Flojet 12 volt water pump manual,” and also search for a photo of a pump’s motor label via Google Images. The Lippert pump, for example, mentions a 5/10 duty cycle on their motor label, but nowhere in their various literature, catching shower users by surprise after purchase and installation.
So, lots of pumpy electronic word thingies there. Hope this is helpful! I have to go console my German Shepherd now...
