PART #2 OF 8
IS THE HYDRO-OBLITERATOR PUMP THE PROPER REPLACEMENT FOR MY OLD MEGA-WATERSLAYER PUMP?
That's a common question on websites, although more likely mentioning other pump brands. The answer is generally yes. Common aftermarket pumps are generally meant to be fairly universal replacements for OEM, and they all typically have the same plastic 1/2 inch x 14 MNPT (National Pipe Taper - male - 14 threads per inch) inlet/outlet like your OEM pump. (Note that the similar, but metallic, 1/2" fittings at Home Depot/Lowes may not have the same threads as the universal plastic connectors that come with new pumps, the latter available online via a search of "Shurflo NPT." But the "SharkBite" connectors at hardware stores MAY work.)
So you just need to ensure that your replacement pump has similar GPM flow (gal per min), comparable PSI pressure (pounds per square inch), and a compatible electrical fuse amperage. Compare the spec label on your OEM pump to the specs for a replacement, and also check your RV fuse box pump amperage as well. If your current pump is not original, don't assume the installer made the right pump choice. There may be a date of manufacture on your pump label that jives with your RV's model year, ensuring it’s OEM.
HOW MUCH FLOW?
Simply mimicking your OEM pump's specs is fine since you're deferring to the RV manufacturer. Otherwise Flojet suggests 1 GPM per water fixture (sink, shower, toilet, washer, etc.) under simultaneous use. If you just anticipate a sink and toilet operating at the same time, then a 2 GPM pump may suffice, although a higher flow pump won't be harmful, you simply won't fully utilize its capabilities. Flojet states that 1/2" barbed hose fittings (and therefore the entire water system) can flow up to 4.0 gpm. For yet more flow, one would presumably need to upgrade to 3/4" hose, with fittings that max out at 7.0 gpm, or eliminate all constricting "insertion" fittings such as barbed connectors, which all these flow numbers are based on. Lastly, 2.1 gpm max for 3/8" fittings. Being the smallest diameter part of the hose system, fittings are the limiting factor in regards to flow other than pump gpm rating.
