Shurflo 4008 water pump

[moallen]

The manual says the #1 cause for pump back flow is failing to sanitize the water system regularly. I'll admit I've only sanitized it once in the 10 months I've owned it, but I didn't feel the need since we use it regularly. Maybe it depends on the amount of calcium, iron, etc in the water. In any case, I plan to sanitize more often.

[Houston Remodeler]

While on our 6 week road trip our check valve failed too. To repair on the road I added a $7 brass check valve just before the pump. That made things worse by making the pump cycle one or two clicks at a time 24 hours a day. Very annoying. I moved the check valve to after the pump. That solved the problem but now the pump sounds like an outboard motor. We don't use it much so it hasn't been all that annoying.

I will look into cleaning the original pump and see if that solves the problem. If we boondock more I will be tempted to replace the pump.

[jcarlilesiu]

That seems odd l, but agree that inspecting the check valve as the culprit is probably the best.

If hooked up like that again, maybe just good practice to keep the low point drain open?

Sent from my SM-G925V using Tapatalk

[moallen]

We're about to head home after spending 4 ½ months in our Starcraft 24rls. I thought I'd share some of the problems we encountered and how we dealt with them.

It's easy to forget about the fresh water tank when hooked to campground water for months at a time, but it's important to keep water in the tank and use it occasionally to prevent bad things from growing in the tank.

In doing that I discovered city water was flowing backward a little through the pump and eventually overflowing the tank. The Shurflo 4008 pump has a built-in check valve that is supposed to prevent this. Since my 24rls is fairly new and I've always used a filter on the hose, I suspect construction debris is keeping the check valve open a little. The solution is to take the pump apart and clean it. I'll do that when I drain the system back home. But for now I just close the winterizing shut-off in the suction line when I'm not using the pump.

The 1st picture shows the water flow when using the pump. The pump draws water out of the tank at point A and pumps it into the trailer's water lines at point B.

The 2nd picture shows the flow when the check valve in the pump has failed and is letting city water flow backward through the pump into the tank. Closing the winterizing shut-off prevents the flow until the check valve in the pump can be disassembled and cleaned.

IMG_2681p.jpg (164.43 KiB) Viewed 1411 times

IMG_2681c.jpg (167.14 KiB) Viewed 1411 times