saflyer Posted October 18, 2023 Share Posted October 18, 2023 (edited) My 12v water pump doesn’t shut off even with all the faucets closed. This problem just started last week. How can I decide if it’s a leak in a line or the shutoff switch is bad. If the latter I would think the tone of the pump would go down and it would slow down but not stop. Where is the pump switch, internal to the pump or external? I am sure every faucet is turned off. Any suggestions on where to start? Ed ‘05 HR Ambassador Edited October 18, 2023 by saflyer Clarity Link to comment Share on other sites More sharing options...
Dr4Film Posted October 18, 2023 Share Posted October 18, 2023 (edited) So where is all of the water that the pump is pumping going to? Pull the the 12 VDC Fuse that powers the water pump to shut it down. Edited October 18, 2023 by Dr4Film Link to comment Share on other sites More sharing options...
DavidL Posted October 18, 2023 Share Posted October 18, 2023 pump check valve might not be closing so water is recycling and pump isn't shutting off due to no pressure built up. Link to comment Share on other sites More sharing options...
Tom Cherry Posted October 18, 2023 Share Posted October 18, 2023 13 minutes ago, saflyer said: My 12v water pump doesn’t shut off even with all the faucets closed. This problem just started last week. How can I decide if it’s a leak in a line or the shutoff switch is bad. If the latter I would think the tone of the pump would go down and it would slow down but not stop. Where is the pump switch, internal to the pump or external? I am sure every faucet is turned off. Any suggestions on where to start? Ed ‘05 HR Ambassador I’m betting on an UPSTREAM as in on the suction or inlet line. A pump with a pinhole leak in a line or a loose fitting will never build pressure to shut off. Even a NEW PUMP ain’t gonna work. Only way….I know….remove the inlet. Plumb in a temporary line….extend it out and drop into a 5 gallon bucket of water….pump shuts off….air leak. Pump doesn’t and there is no flooding or such….bad pump 5 minutes ago, DavidL said: pump check valve might not be closing so water is recycling and pump isn't shutting off due to no pressure built up. Maybe, but on most Monaco’s there is a built in check on the pump outlet. That check is used to prevent city water from back flowing into the fresh tank. So, when pump runs, it opens the check and lets water flow into the system. The OTHER check valve in on the incomig side. That check prevents the pump from shooting water out the inlet hose. If the water hose is NOT hooked up and there is no water coming out of it….no way to recirculate…at least on the plumbing diagrams I have seen…. The Fill side of the City/Fill valve diverts water to the fresh. YES….a leaking fill valve COULD do that…in theory. Easy way to test….cycle the fill/city valve several times. Then leave in the city position. Turn on the pump. Open the cap on the fresh. You would hear it or see bubbles or agitation. Calm level….not the check or fill Link to comment Share on other sites More sharing options...
BradHend Posted October 18, 2023 Share Posted October 18, 2023 (edited) Have you purged the water system of any air? Try checking every tap - turn the water on for a bit - hot and cold. And for sure supply side valves are open and there is water in the tank. 😉 Edited October 18, 2023 by BradHend Link to comment Share on other sites More sharing options...
waterskier_1 Posted October 18, 2023 Share Posted October 18, 2023 There are a few different things to check. First, do you have about the same water pressure as before this problem occurred? Second, I've read many posts about not having the "City" and "Fill" Valves set to the correct position. I don't have those valves, so I can't elaborate, other than to say that if they are set incorrectly, you just recycle the water in the fresh water tank. The most common problem I've experienced over the last 45 years, especially on the houseboats, which suck water directly from the lake, is a small piece of dirt gets in the internal (to the pump) check valve, which keeps it from properly closing. In past years, you could get rebuild kits with new parts, and servicing the pump would correct the problem. This didn't happen near as often in the RVs, likely since the water I put in the tanks was clean. There are other check valves in the plumbing system too. I don't think your Ambassador has a water manifold where you can turn off individual water lines, but you can disconnect the output of the water pump and plug (cap) it. Then restore (assuming you followed Tom's suggestion that you pull the fuse to shut it off) power, and see if the pump builds pressure and shuts off. I forgot to mention that there is also an internal (to the pump) pressure switch would could also be bad. If the pump builds pressure and shuts off, you know you problem is after the pump. If it doesn't, the next thing I would try is removing the input to the pump, and temporarily connecting a piece of tubing long enough to go from the pump out to a bucket filled with water. Again, restore power and see if the pump shuts off. If so, you know you have a problem before the pump, if not, the pump internal check valve or pressure switch is likely bad. I don't think you can be repair kits, by you might check with the manufacturer of you specific pump. Post results and we might be able to further advise, as it is impossible to cover all possibilities. -Rick N. Link to comment Share on other sites More sharing options...
Frank Bergamo Posted October 19, 2023 Share Posted October 19, 2023 1 hour ago, waterskier_1 said: Second, I've read many posts about not having the "City" and "Fill" Valves set to the correct position. This is where I would start. If manual, make sure it is in the proper position. If electric, it will probably be a red hat valve possibly stuck open. Hope this helps. Link to comment Share on other sites More sharing options...
Happycarz Posted October 19, 2023 Share Posted October 19, 2023 You more than likely have a filter screen on the inlet side of the pump. It has a clear see through plastic bowl on the bottom. Two things happen with it: The bowl becomes loose and needs to be hand tightened, or a small crack can develop in the bowl. If cracked just buy a new inlet filter. The inlet filter would be a good place to look. Below is a picture of mine. Sorry as it is only a picture from the top. But you can see the gray ring, with the bumps on it, that you tighten. There is an O ring on the bowl. Hope this helps. Link to comment Share on other sites More sharing options...
Tdkkart Posted October 19, 2023 Share Posted October 19, 2023 I'm voting for a valve in the wrong position as well. If I hook up the hose and turn on the valve to fill the fresh water tank and don't shut the pump off it will run continuously until the valve is shut off. Otherwise it's possible you have a leak somewhere, toilet valve stuck open maybe? toilet flush pedal stuck all the way up?? This why I don't use the city water connection for anything but filling the fresh tank. I fill the tank and then let the pump do it's job as it's supposed to, the difference in water pressure isn't very much at all, and although I have to listen to the pump I consider hearing it work as a good way to monitor the system for leaks. As long as the pump is able to build pressure and shut off it's all good, no leaks to worry about. Link to comment Share on other sites More sharing options...
Solution jrelmore7 Posted October 21, 2023 Solution Share Posted October 21, 2023 Make sure your fresh water fill valve is closed. If it is open the pump will stay running' Link to comment Share on other sites More sharing options...
Melvin Posted October 22, 2023 Share Posted October 22, 2023 On My 2001 signature if you are plugged into city water and turn the valve to fill your tank and don't remember to close the vale back. your pump will run continually when turned on because the fill value being still open creates an open circuit for the water to run back to the tank. close the valve and the pump will build press ure and shut off. Link to comment Share on other sites More sharing options...
saflyer Posted October 22, 2023 Author Share Posted October 22, 2023 On 10/21/2023 at 5:54 AM, jrelmore7 said: Make sure your fresh water fill valve is closed. If it is open the pump will stay running' This might be it. Solved the problem yesterday. Will try again today. Link to comment Share on other sites More sharing options...
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