Water going from hot to cold when using pump.

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Ned said:
Dennis, I know, I was only addressing the pump cycling with several faucets open.  That may be normal and not part of the original problem.
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my bad...thinking out loud.  ;D
 
I have an accumulator on my 03 and if the charge air press is correct their is a slight delay in pump start-up after turning on a faucet. Then when acc. psi is exhausted the pump comes on and runs until the faucet is shut off and water psi to the acc. is returned. The pump should not cycle every couple seconds IMO. If it is then I would check charge air pressure which I think on mine is around 20 psi to the bladder. This however would not interfere with the water temp, at least from what I can think of.
Also, what about a winterizing line partially open allowing the pump to suck air? I'm referring to the one that gets inserted into the bottle of antifreeze to draw into the water system. I don't really use mine so not sure this would cause a problem but might check to see that the gate valve is closed and the winterizing switch didn't get turned on by accident. My switch is right below the hot water tank switch.
 
I'm still trying, but nothing seems to be working....  I'm almost certain it's the nut holding the handle, but I don't know what I'm overlooking... 
 
If both hot and cold valves are turned on at a fixture (especially a shower fixture with a hose and shower head that runs up the wall) and the pump cycles off with those valves open thereby relieving the pressure, it allows the hot and cold side to mix in the valve. Then when the pump cycles back on, you're likely to initially get a shot of colder water. Since back pressure is what causes the pump to shut off, and there is no back pressure with valves open, it seems to me that there must be some failure on the pump end of the line. I think it could be as simple as a loose connection on the 12 volt pump wires, a valve in the supply side that is just barely open, or the pressure switch within the pump.
 
I have a new to me coach. We took it out on a shakedown camp out. The water system worked just fine on the city water connection. It was very erratic when using the pump from the tank. What I found was that the dealer had winterized the coach and left the valve open that goes to the tube that is used to suck antifreeze into the system. It was full open. I would also suggest that you look at that valve. Once I closed that valve the water system with the pump worked as it was supposed to..
 
I've tried everything.  Now I'm getting frustrated.  I guess ill get an expert to look at it...damn

I found some more stuff to read in addition to all thie great information...and it seemd to boil down to a possible leak in the system somewhere.  Which is the same as a valve not closed all the way which was mentioned.  But I'm sure every valve is in the correct position, and securely on or off. 

There's no water leaks anywhere I can find, so that would leave a leak somewhere else (air or water)

I guess I'll start at the tank and work my way back....  LOL

 
codgerbill said:
I have a new to me coach. We took it out on a shakedown camp out. The water system worked just fine on the city water connection. It was very erratic when using the pump from the tank. What I found was that the dealer had winterized the coach and left the valve open that goes to the tube that is used to suck antifreeze into the system. It was full open. I would also suggest that you look at that valve. Once I closed that valve the water system with the pump worked as it was supposed to..
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I don't think I have such a tube...  I have the valve for the drain pipe.  Another valve to drain water on the far side of the coach, one for cold and one for hot at the water control station.  The water heater bypass valve. And that's it i think.

PS  I did open every faucet and the pump seemd to work fine...dunno if that's a clue or not....  :)
 
I've tried everything.  Now I'm getting frustrated.  I guess ill get an expert to look at it...damn
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Rob, it seems to me (I?m easily confused!) we need to sort out a few things and go back to one issue at a time. Please clarify if I am wrong here.
I think you have two complaints; when using the fresh water tank the water pump cycles on and off electrically, meaning it completely shuts off, even when a faucet is open.
AND, when the pump cycles off and on your hot water temp also cycles back and forth from cold to hot.
Is this correct or have I misunderstood?
IF this is correct, then I would disconnect city water and start on the water pump problem to see why it is physically shutting off with a faucet open. I?m assuming you have low line pressure here when you open a faucet. You can verify this by shutting all faucets inside and working the outside shower valves right at the pump location and verify exactly what happens.
Do you have an accumulator and have you checked the air charge? It is sort of a shock absorber for the water lines and it does help to keep the pump from cycling with small amounts of water pressure change.
Could be a bad pressure switch or a number of things incl. the pump or motor but too early to tell. I would recommend you sort out the pump problem (supply) first and the water temp problem might be solved also. I am getting mine ready tonight for a short weekend trip so if you need anything checked for comparison just let me know.
 
Mavarick said:
Rob, it seems to me (I?m easily confused!) we need to sort out a few things and go back to one issue at a time. Please clarify if I am wrong here.
I think you have two complaints; when using the fresh water tank the water pump cycles on and off electrically, meaning it completely shuts off, even when a faucet is open.
AND, when the pump cycles off and on your hot water temp also cycles back and forth from cold to hot.
Is this correct or have I misunderstood?
IF this is correct, then I would disconnect city water and start on the water pump problem to see why it is physically shutting off with a faucet open. I?m assuming you have low line pressure here when you open a faucet. You can verify this by shutting all faucets inside and working the outside shower valves right at the pump location and verify exactly what happens.
Do you have an accumulator and have you checked the air charge? It is sort of a shock absorber for the water lines and it does help to keep the pump from cycling with small amounts of water pressure change.
Could be a bad pressure switch or a number of things incl. the pump or motor but too early to tell. I would recommend you sort out the pump problem (supply) first and the water temp problem might be solved also. I am getting mine ready tonight for a short weekend trip so if you need anything checked for comparison just let me know.
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Thanks...sorry about the confusion.  Let me try to clear things up....  :)  You really do have the gist of it....and I think you hit the nail on the head with the pressure problem, as far as THAT's the root of the entire issue. 

The city water is disconnected.  I turn on the shower hot and cold water (or any other faucets) and the pump starts cycling on and off every few seconds.  When the pump comes on you get a shot of cold water and when the pump goes off it the water goes back to normal, which is a nice warm shower temp.

I looked and looked for a accumulator.  There isn't one on the plumbing schematic.  And I don't know where to look or what it looks like if I did find it.

I cleaned the pump screen.  I made sure all valves were tightly closed.  The hot water by pass valve is on the flow position. 

I'll search the web for accumulater info and take that route tomorrow.  Thanks again for entertaining the newbie crap.



 
Rob, I have attached a couple pics of my water bay with accumulator. Sorry about the quality, had to use my phone because my camera died.
001a is a close up of the accumulator I have. You can see the air valve (tire stem) on top for filling bladder with air. You may or may not have this but mine is in the water/electrical bay towards the back.
002a is another shot of the bay showing the accumulator towards the back, the outside shower controls and the fresh water hookup. The water pump is above the electrical to the right, just out of the picture. If you do have an accumulator it should be easy to find and needs an air charge to the bladder for proper pump operation. If you don?t have one then I would start with the pressure setting which turns your pump on and off electrically.
One other note about 002a, the clear hose in the pic with the white cap is the one I was talking about using for sucking antifreeze out of a bottle to winterize the system. I have an electric control switch inside so no manual valve to operate. Just make sure this is closed or shut off. Mine was rolled up and kind of hidden in the back of the bay so until I found the electric switch I didn?t think I had one installed. Good luck & keep us posted.
 

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Mavarick said:
Rob, I have attached a couple pics of my water bay with accumulator. Sorry about the quality, had to use my phone because my camera died.
001a is a close up of the accumulator I have. You can see the air valve (tire stem) on top for filling bladder with air. You may or may not have this but mine is in the water/electrical bay towards the back.
002a is another shot of the bay showing the accumulator towards the back, the outside shower controls and the fresh water hookup. The water pump is above the electrical to the right, just out of the picture. If you do have an accumulator it should be easy to find and needs an air charge to the bladder for proper pump operation. If you don?t have one then I would start with the pressure setting which turns your pump on and off electrically.
One other note about 002a, the clear hose in the pic with the white cap is the one I was talking about using for sucking antifreeze out of a bottle to winterize the system. I have an electric control switch inside so no manual valve to operate. Just make sure this is closed or shut off. Mine was rolled up and kind of hidden in the back of the bay so until I found the electric switch I didn?t think I had one installed. Good luck & keep us posted.
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Thank you....  Guess what I'll be doing first thing on the am...  :)
 
You need to remove both of the winterizing valves located behind the heater. You can not see if they are bad. You must remove them and replace them.. They are your problem. When you run the pump you apply pressure in the check valve and the loose rubber inside clogs up causing no hot water to come out. That is why you still feel the cold water. It works fine and has nothing to do with the valve. When you turn the pump off the rubber clears and you get hot water. The city water connection does not have the same pressure so the rubber does not clog the valve.
 
Agree with livingthedream -  the hot/cold problem is most likely the check valves at the water heater.

Some water system basics:  The pump cycles based on pressure. It is typically set to maintain 45-48 psi, so when the faucets are all closed it pumps until it reaches about 45 psi and shuts off. When a tap is opened (or there is a leak), pressure drops and the pump comes back on. Most pumps can pump water faster than it exits the faucet, so the pressure rises to 45+ and the pump shuts off for a few seconds until the pressure drops again. This cycle continues indefinitely.  You cannot make any firm conclusions based on cycling with the faucets open. A larger pump can push more water, so you have to have several faucets wide open to make it run continuously, whereas a smaller pump can be forced to run 100% with just a single faucet wide open.

Your Bounder did not come from the factory with an accumulator in the water system, so you won't have one unless you (or a former owner) added it.
 
I appreciate all the answers, but I'm getting in over my head here...I can't find any of those things you all are writing about.  Here;s a picture of all I saw. 

The RV repair dude is coming on Monday, to look at one of the jacks...i'll get him to check out the water situation as well.
 

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Here is a link: http://www.campingworld.com/shopping/item/quick-turn-by-pass-kit/15717

Note the brass on and off valve. You should have two of these near the heater. 1 at the cold water in and 1 at the hot water out.  Remove them and bypass them for the test.

Once you are sure then just order new ones and replace.
 
My embarrasment is someone elses solution I hope. 

The RV guru simply increased the pressure by turning the adjustment screw.  It's on the top of the pump where I couldn't see it, and I didn't have the manual for the pump.  I do now.

Thank you all for the imput....
 
More water pressure probably just covers up a weak check valve, i.e. the greater pressure forces the valve closed so it doesn't cross-feed. My bet is that the problem comes back in a few weeks or months, after the valve gets worse..
 
same thing happened to me this week end first time out with my camper. the valve between the hot water outlet and the cold water inlet was closed. this is the cut out used when winterizing so anti freeze dosen't, go into the hot water tank
 
Gary RV Roamer said:
More water pressure probably just covers up a weak check valve, i.e. the greater pressure forces the valve closed so it doesn't cross-feed. My bet is that the problem comes back in a few weeks or months, after the valve gets worse..
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You could be right Gary, however the water pressure was actually very very weak.  Now that it's back up, the pressure seems great and the tempature maintains well.  I'll still keep an eye on it and at the first sign of a repeat issue at least I'll know how to troubleshoot it.    THANKS AGAIN!!!
 
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