Leak in feed to hot water heater

[boxers-rule]

I've discovered a possible leak between the water manifold and the Atwood tankless hot water heater in my 2015 Berkshire XL 40BH. Does anybody know the accessibility to this line? I can't get the unit into the dealer for 3 weeks and I'd like to figure out before hand how to access this line.

[Campin Cajun]

I'm not sure how that line is routed. Do you see a visible leak somewhere that you suspect that line?

[boxers-rule]

I've isolated the leak to behind the wet/tank bays and only when the water heater is turned on.

[I-RV]

It is weird that you only get a leak only when a faucet flows hot water, I say this because there is water pressure in all the lines to the heater, to the manifold and to each faucet, all the time and if there is a leak, one would think that it would leak all the time. Unless the leak is temperature sensitive, which is generally not the case.

I had a crazy situation that drove me nuts and not to say it is your problem, My bathroom sink faucet would leak underneath only when turned on. I found that when I took the aerator off to clean it, I did not put it back properly. When the faucet was turned on, water squirted out into the plastic water spout and back to where the faucet was mounted and down into the cabinet. LOL - my bad!

[boxers-rule]

By process of elimination, I had discovered (surprisingly) that the leak only seems to rear its ugly head when the water heater switch is ON. I had noticed a drip line when the unit was parked facing downhill (obviously water won't flow uphill), behind the tank/wet bays but only after systematically going thru a few situations.
1) Water pressure (with pump switch ON), no leak.
2) Water pump ON with outside shower cold or hot ON, running separately (with water heater OFF), no leak.
3) Water pump ON with outside shower hot (with water heater ON), leak formed. Note that I'm having a further complicating problem of the Atwood Water heater not lighting most of the time and it wasn't lighting during this testing either and no apparent leak within the actual Atwood unit)

No other faucet fixtures were turned on during this test.

I am assuming the water line runs from a manifold situated behind the conglomerate of plumbing in the wet bay, under the floor of the bedroom (carpeted) slides (both bed and wardrobe) BUT above the basement ceiling, since I can't see an exposed line in the basement. I guess it's possible it runs thru the transmission/engine bay but I find that improbable.

It has me concerned further because I now note the leak seems to be an old one because of the rust I discovered around the top and bottom of the tank bay. And this unit is brand new, just purchased in May and built a few months ago.

[edgewant]

Sorry to hear of your problems. That's a tough one.

I have a 2013 390RB with the rear floor area elevated for the bath room. In the process of running HDMI cable I discovered that the rear sinks and toilet drain lines run through a chase that goes along the street side of the bedroom. I believe I also recall seeing PEX water lines in there.

I know our layouts are different but you may want to check there.

Also I believe there are PEX lines in the rear most lower compartment that enter into the compartment and the hot water heater sits above it.

Sorry I can't be of more help.

[dan-nickie]

If I'm following your diagnostics, it seems that turning off the outside shower hot valve on the water manifold should stop the leak.
Right?


I normally keep that one turned off anyway as I seldom use the outside shower and never the hot outside.

[edgewant]

Just went out to the barn and checked. I was wrong about the lines running through the curb side lower compartments. But I was correct about them passing through the chase on either side and below the bed.

[edgewant]

The chases are not permanently attached to the floors or walls so they can easily be removed to check for any leaks there.

[I-RV]

Originally Posted by boxers-rule

3) Water pump ON with outside shower hot (with water heater ON), leak formed. Note that I'm having a further complicating problem of the Atwood Water heater not lighting most of the time and it wasn't lighting during this testing either and no apparent leak within the actual Atwood unit)

It has me concerned further because I now note the leak seems to be an old one because of the rust I discovered around the top and bottom of the tank bay. And this unit is brand new, just purchased in May and built a few months ago.

There is only one line from your water heater to the manifold and not a separate line for the outside shower. That is why they call it a manifold. As you stated, with the outside shower hot off; no problem. Not sure which off valve you are talking about; the manifold valve or the shower faucet valve. Either way, the problem is with either the manifold valve, the line from the manifold valve to the shower valves or the shower valve. Therefore your problem is right there in the wet bay. Leaks can be sneaky, you may not see where it starts, but water travels downhill and you see it where it comes out (which gives you often a false impression as to where the leak is).

[boxers-rule]

Thanks to all who are helping me try to sort out the issue.

I don't believe that the leak is actually tied into the outside shower. I only turned on that valve because it was closer than running up and inside to turn on a faucet.

With that said though, I will be doing each faucet separately now to verify my diagnostics.

[boxers-rule]

Hank, the leak is definitely on the backside of the tank/wet bay and is coming out from the frame directly in front of the back wheel, on the leftside frame of the tank/wet bay, above the basement ceiling AND the rig is in my sloped driveway with the front end lower.

See pix for actual location of drip/leak.

[I-RV]

Sorry for my misinterpretation, but I thought that you were talking about the wet bay on the drivers side.

Yes in the wet bay on the passenger side, there is many valves and couplings and chances for a leak. By opening up the not too convenient door and poking around, should be able to see where the leak is. It could just be that one of the valves like the anti-freeze insertion valve is not quite shut. You have to get down on the ground and remove the two clips holding the compartment door closed. Then you need someone to hold the door up. As I said, "Not too convenient". Good Luck

[boxers-rule]

Hank, in the picture I posted you can see that I have the what I call the tank door open. I prop it open with a long board (in pix).
Are you referring to the bypass valve to allow you to draw anti-freeze into the system (instead of pulling water from the fresh water tank)?
If so, that valve actually sits at the basement (tank) floor level. The drip/leak is above there, at the hinge area, top left.

[conceptumator]

Possibly a dumb question, but have you checked the pressure relief valve inside the heater cabinet to make sure it's not popped or leaking? That would release water into the heater cabinet, which could then follow any line coming into or out of the cabinet to a lower point, then dripping. Just a thought, but very easy to check. The pop off valve is immediately behind the control panel on the left side of the cabinet after you remove the access door. Good luck.