New to RVing... need help with fresh water filling

[asapautoglass]

Recently purchased a 1992 cruise master by georgie boy. Chevy chassis reasonably good condition for what it is... got it cheap. I am having trouble filling the fresh water tank. There does not seem to be a fresh water inlet anywhere on the outside of the coach. In the storage tank bay there is a hose bib. Following the instructions in the manual and the diagram in the bay I connected a hose to the inlet. There is a valve located directly below the inlet connection and I started by operating it with the valve closed so that the plumbing was operating off of city water. Opened the taps on the sinks and the shower and after some air worked its way out I got a nice flow of clean water. Checked under the coach and no leaks.

Next, following the instructions I opened the valve so that water could fill the fresh water storage tank. The first time I did it the water, instead of flowing into the fresh tank, flowed into the grey water tank. I am sure of this because a) I could hear it and b) I just dumped the grey tank and when I opened it again it had clean water in it. I shut everything off and started back at square 1. This time I got nothing at all. No water flowing anywhere in the coach. No leaks fortunately but no success either.

My fresh tank and pump are located under the bed. The pump runs just fine. It is a Shurflo with a mfg date of 2001 so it has been replaced at some point. We removed the plumbers strap holding the tank in place so we could inspect the underside. Here's where I'm stumped. The only unplugged openings on the tank are the two overflow tubes and the single outlet for the pump. There is no other plumbing going to the tank. The pump has an inlet from the tank and an outlet which Ts off into two lines- I assume one to the hot water tank on the pass side and one to the lavatory and kitchen sink on the drivers side.

We removed the lines at the T and reconnected the city water, again following the fill instructions per the manual. We got water coming back thru the lines towards the pump. Now I know that the pump has a check valve to prevent water from going backwards thru it and overfilling the tank but that would seem to be the only way that you could get water into the tank. Is the pump supposed to be able to allow water to flow back through it to fill the tank? I had considered permanently installing a fresh water fill hose to one of the other openings on the tank but I don't want to do extra work or mess something up if there's something simple I'm missing.

[asapautoglass]

Got Coach working... I removed one of the overflow tubes (there were 2 so I still have one) and connected an adaptor nipple to the opening where that overflow was. Installed a short hose to that connection and ran it through the hole in the floor where the overflow tube ran. Sealed around the hole with urethane adhesive. Mounted the other end of the hose in the bay behind the electrical bay so it would be separated from both the electrical stuff and the waste tanks. I filled the tank, turned on the pump, and everything works like a champ!

Thanks a ton to everybody who took the time to read and respond to my question... being a noob to RV I'm sure I will have more! I do auto glass for a living and I've done a bunch of RV windows so if anybody has glass questions please feel free to PM me.

[Yankee_Clipper]

RVs are not designed to cross-connect the fresh water and sanitary tanks. Could you imagine the lawsuits? Anyway, I have seen rigs that have separate sanitary tank rinse inputs that are separate from the potable input. Could that be what you connected your hose to?
Hope this helps.

[Executive45]

While I admit I'm not familiar with your rig, the manual certainly specifies what you're supposed to do to fill the tank. According to Page 23, you simply turn the valve 1/4 turn to fill the tank. If you're doing that and it's not filling, I was simply suggesting that you start with the valve. The valve's probably original so it's at least 22 yrs old. I'd take it apart and see how it works...that said, why not bypass the PUMP and see if the tank fills. If it does then you problem may be that there needs to be a "Y" so that the valve when turned 1/4 turn fills the FW tank and when closed the fresh water is fed to the pump. I hope that's clear...if not, let me know or send me a PM....Dennis

[asapautoglass]

I'm totally with you on not wanting to do more work than necessary. However, I am not sure how the fill valve could be causing my issue. The valve definitely does SOMETHING... we established that putting the valve into the "closed" position- that is, the position indicated by the manual and by the instruction placard in the holding tank bay- redirects fresh water through the lines back to where the tank is located. What has me confused is that there does not seem to be way for the water to get into the tank except through the pump which would require the water to flow through the pump in the direction opposite of the normal pump flow.

[Executive45]

Maybe it's as simple as your fill valve is bad. Remove it and check to ensure it's working properly...Personally, I wouldn't try to reinvent the wheel....just sayin....Dennis

[Dale_Traveling]

asapautoglass wrote:
I'm starting to side with the someone screwed something up theory. I have lifted the tank up and I am sure that there are no other inlet openings. So I guess I'm gonna run my own fresh water fill line to the tank and see what happens. Either I'm gonna make it work or instead of a motorhome I will have an ark

I'm thinking the same, prior owner alteration. Call it a PO-Alt. Use one of the overflow lines. Install a hose connection with a cap. Add water until it comes out the other line.

[asapautoglass]

OK I thought I mentioned this but... I downloaded the manual. I found the valve in question. I turned the valve 1/4 turn. The valve only turns one way and it will only turn 1/4 of a turn so I know I'm doing that correctly. Also there is a diagram on a sticker inside of the holding tank bay that shows the correct valve alignment. I have turned the valve as specified in the manual and as specified on the sticker inside the holding tank bay. The problem I am having is not getting water through the valve and back to the rear of the coach where the tank is located. Water flows through the tubes and back to the tank area. The problem is that the line through which the water flows seems to be set up to try to push the water through the pump in the direction opposite of the pumps normal flow direction. I am trying to figure out if this is correct and I am not doing something else right or if perhaps someone has incorrectly installed the fill lines. Rest assured that I have read the manual. I have also read the Shurflo installation instructions. I have also read the ehow articles on troubleshooting RV tanks and pumps.

[Rallye2000]

Look on page 22 of the manual you downloaded at the link in above post. The city valve is opened 1/4 turn while the city water is connected to the coach. That fills the tank. It's on page 22 in the manual.

[asapautoglass]

I'm starting to side with the someone screwed something up theory. I have lifted the tank up and I am sure that there are no other inlet openings. So I guess I'm gonna run my own fresh water fill line to the tank and see what happens. Either I'm gonna make it work or instead of a motorhome I will have an ark

[Bill_Satellite]

The water pump does have a check valve so water will not be able to flow through the pump and into your fresh water tank. Also, the water line running from the pump to the city water valve should also be correct. Turned one way it would allow city water into the coach (not the tank) so you don't need to use your holding tanks or pump. Turned the other way you would be using your holding tank water and water pump as your pressurized water source. There should either be a third option on the valve (fill) or a separate connection somewhere that gives a fill option. Is there no "gravity fill"? I am assuming not since you say there are only 2 lines connected to the tank.
If you can fully see all 4 sides of the tank and the only 2 connections to the tank are the 2 lines that run directly from the tank and out the floor as drains then someone has really screwed something up.

[asapautoglass]

The two overflow tubes go straight down through a hole in the floor and both come out under the rear of the coach right next to the trailer hitch. You can clearly see the ends of both of them. The lines coming off of the fill valve are a little trickier. There seem to be two lines- one of which is the aforementioned line going back to the pump- which run through the back wall of the holding tank bay but they must run through the "subfloor" of the coach if there is such a thing because they are not visible from underneath the coach. From the direction it runs I am going to guess it is going to the hot water tank.

BTW in case it matters the HW tank is full (we cracked open the drain out and got both water and pressure) but I can't find any way to access the other side of the HW system where it's fill line would be

[WyoTraveler]

oops, double post.

[WyoTraveler]

Many of the MHs have that valve system. Mine has it also. I am sure from brand to brand or year to year there may be some differences but when I am on city water I can get water at the fauset. I don't open any valves inside. There is an overflow for the tank. I just leave all valves shut off and turn the valve and it starts filling the tank instead of furnishing it to the fausets. I am wondering if there is a check valve that isn't working because you are opening valves inside the coach.

[Dale_Traveling]

The pump movement when you tug on the line would be correct and yes the pump should have a check valve to prevent back fill when on city water. Any chance of following the lines from the fill valve and the two overflow tubes coming off the tank?