2006 Tiffin Phaeton water leak by refrigerator

found this

My 2004 Bay 34XB also has a 2 FW tanks=84 gallons setup that requires the sidewall manual water fill cap be opened in order to vent properly to fill the 2nd tank. Perhaps yours is similar. Weight distribution on this model places them aft of the front axle. My tanks are under the salon area, just behind my battery box / entry steps.

I also have a drain **** located between the 2 tanks for draining both at once. There is a circular cut-out hand access hole in the wall of the basement plenum [to operate the valve]. Located 1st basement box aft of the steps. With a mirror you can peer into the plenum and see edges of both tanks. they are perhaps 8-10 inches apart. This should help you find them.

https://www.google.com/search?q=2009+Tiffin+Allegro+Bay+fresh+water+tanks

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Question edited to merge both your posts into one.
Question moved to RVS.

Here is the manual for your RV. There are 94 mentions of the word 'heater', and they all refer to the tankless water heater. I wonder if your is an aftermarket add-on? Phone them up.
https://tiffinmotorhomes.com/pdfs/manuals/2011_Phaeton_Owners_Manual.pdf

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Plastic water Pipes run along the inside floor close to the Outside walls of the Unit.

It is not likely a flat tire would puncture a Water line but, possible the Unit's Storage tank water line went higher than the Tank Vent when tipped on the Drivers side due to the flat tire or more likely a Pipe Joint became separated during a cold spell and became evident with vibration of the flat tire.
https://crossroadsrv.com/image/data/OwnersManualPDF.pdf

More information? You'll need to talk to your Dealer?

There is no overflow pipe on the water heater. There is an overflow/vent pipe on the fresh water storage tank though. It is normal for this to leak water at times.

Its possible you might have some type of winterizing hot water tank drain. But that should have a valve on it. If you have such a valve it should be shut off and not leaking.

That said we move on to the water heater. This is assuming you have a water heater leak. Or a leak with something connected right at the water heater.

You could expand this concept to move on to other pressured parts of your plumbing system to troubleshoot and isolate.

I would remove the pressure relief valve and rig up a fitting you can screw in. Set up with a pressure gauge and a air filler fitting like is on an inter-tube/tire. Some plumbing stores sell them already made up.

You might have to custom adapt this using some rubber hose rated for air compressors. Using barbed to threaded fittings and hose clamps to withstand pressure.

Install your air valve/gauge in place of the relief valve. If you have bypass valves this is a little easier. Close off the bypass valves to isolate the tank from the plumbing system.

If your plumbing set up has no bypass valves, disconnect the inlet and outlet plumbing lines. Screw in appropriate sized plugs in the two tank holes. Use teflon tape and make sure they are secured. (All easier said than done).

With an air compressor or tire pump pressurize the tank to 50psi. Soap all fittings, and your plugs, to insure you have no leaks around anything screwed in. Let this sit overnight. If your pressure drops off you have a leak. If your pressure holds I would suspect the relief valve that you removed.

You could move your air valve/gauge set up to the water inlet or outlet pipe and reinstall the relief valve, to test the relief valve. Pressure up to 50psi and soap everything again. Let it set overnight again.

If you suspect the relief valve before any of this troubleshooting starts, you might just start by installing the air valve/gauge in the inlet or outlet right from the get go.

Tanks often get pin holes on the bottom as they start to corrode through. Hard to visually find in many cases. Pressurizing with air will tell you whether you have a leak for sure. Not get everything wet in the process. Using common sense and a process of elimination, you should find the problem. There are also drain valves and in some cases anode rods that are screwed into the tank and may be a source of the leak? Soap all of these while troubleshooting.

The image is my setup. It is a little more fancy than described. I have a little valve off a T so I can use the little turn wheel and open the valve to relieve pressure without unscrewing everything. That also beats holding in the little spring loaded needle valve of the "tire filler" valve shown sticking out the right side. But I think you will get the idea of the basic concept?

This is not just for your camper, but general troubleshooting.
Drain the water from the belly pan. Hook up water supply to shore water source. With water source turned on, allow some time, 1-4 hours, and check if water has returned to belly pan. If water is present then the problem is with the fresh water system. If no water, either it is a small/slow leak or the problem is not with the fresh water system. Next test the grey water tank by pouring some red food color into the shower or sink drain. Flush it into tank with water. Again, wait for some time, maybe over night, and then check for red water in the belly pan. It may take longer for the leak to appear as the grey water tank does not have pressure. If no water, check the black water tank with green food coloring and same technique. If there is colored water, red or green, in the belly pan, then the leak is with associated with the grey or black water tanks. If no water is present after these tests, then the leak may be very small and it may take days or weeks to have water re-appear. In any event, clear water is fresh water system, red water is grey water system, and green water is black water system. With any of them, checking the tanks themselves and all pipes and connectors to/from should find the leak source. The last possibility is that water is entering the belly pan from a roof or vent leak. Check to see if water returns to belly pan after a good rain. If so, the water may be clear or slightly dirty. If it is a roof leak, I have found the best repair is to use Peel and Seal roll roofing It is light weight laminated aluminum and self sticking. Cutting and applying narrow strips 4-6" wide, will seal any caulked area. It costs $95 (3' x 33') at Lowes. A 30" motor home can be completely covered with three (3) rolls, in half a day. I have re-topped 5 motor homes (one 7 years ago) and no more leaks on any of them. The product was developed to seal the roofing joints of mobile homes. Topping should last 15+ years.

What is suge? Do you mean Sewage?
Anyway, you most certainly did not hook up to the fresh water inlet properly. This will not fill any tank. Get your manual out and read it.
Contact your local service center directly or online here:

Other than a leaking 4 way selector valve the probable cause would be a leaking check valve in the pump.

On the RV the city water and discharge from the fresh water pump are tied together. When on city water the discharge of the pump will have city water pressure on it. If the internal check valve on the pump is leaking, water will flow through the pump backwards and into your fresh water tank.

Typically this requires ether replacing the pump or installing a secondary check valve between the fresh water tank and the pump suction.

The statement is extremely vague. Is it a travel trailer or a motor coach? Motor coach could be dripping condensation from ac while in use. Is it fresh water and only leaks when connected to a hydrant? Does it only leak when sewage is dumped into the black water holding tank? In short, you must determine under what condition the unit is leaking. Then narrow down where it is leaking from and then identify the failed part. RV manufacturers do not publish plumbing diagrams so it is all visual in the diagnostic process.

if leaking from directly from behind toilet, check connection also if leaking from back of toilet. more than likely it is the vacuum valve on back of toilet. $50 dollar part. if not leaking there. pull all drawers in bathroom out. they lift out. if the inlet for the pressurized water is there, it is probably leaking from the inside. it is a $15 part but depending on access, does is leak when hooked up to water from pressure side or does it leak with just 12 volt water system?

Where is your vent for your tank? Sometimes these will create a siphoning action once started and once full, they drain themselves.