92 Sunflyer how do I fill the second water tank ?

[skloon]

For some reason my 34rq has two separate tanks under the bed, the instructions mention hook up hose turn on valve and wait till water runs out the overflow, when I do this it only fills the rear tank, the water fill door at the back has a broken lock but I see that it has a corrugated hose that runs to the front tank only- is this how I fill it or am I confused

[TerryH]

Are you sure you have 1 Fresh water (commonly under the bed), and 1 Grey and 1 Black tank?

[skloon]

Yes two fresh water tanks- plus the black and grey- those I have no trouble filling, it is the fresh water that I have issues with- and they look to be original

[TerryH]

Just to understand, when you say you have

"plus the black and grey- those I have no trouble filling"

what exactly do you mean?

[skloon]

They get filled with the sink shower and toilet- the panel says they are full all the time but I know that is because of the sensors being dirty

[TerryH]

Normal for your year is that the Black fills from the toilet and the vanity sink.
Grey fills from the galley and shower.
Fresh fills from an outboard fill.
Dump your black just prior to a shower - helps wash out you sewer line when you shower.
Two fresh water tanks - may be a PO added one for boondocking. A second tank would likely have a shut-off valve that you may not be aware of.

Bear in mind that when you fill a fresh water tank you are filling with a 3/4" hose. The water entering is displacing the air in the tank.
Hence a vent tube.
Filling too quickly will overwhelm the air vent tube, which is likely of a smaller diameter than the fill. Guess which one wins?
The vent tube for your black and grey is likely 1 1/2", also called a stink pipe.
Difficult to overwhelm.

Not sure if this is your problem, but if you have two fresh tanks it may be an idea to look for a valve between them.

[TerryH]

Further, the sensors are notorious for being inaccurate.

[Rickf1985]

It sounds like you have the normal pressure fill like I have on mine and then in addition you ALSO have a gravity fill tank! That is a sweet setup! Get that door open and see if there is a gravity fill for water in there. I want pictures, I also want to know how they switch over from one tank to the other.

[skloon]

I wont see it again for a couple of weeks- it would make sense as it looks like the hose from the back corner goes to the front tank only- I would have thought that the two would mix- in between them is the engine powered rear heater and it all looks like factory- there are only two valves, one a drain valve at the passenger side of the rear of the front tank then another one beside the pump that I suspect is for injecting pink antifreeze, thats the one with the vicegrip on it

[TerryH]

If you have 1 drain valve for 2 tanks somewhere there must be a tank to tank connection.

[TerryH]

The rear engine powered heater runs solely on your engine coolant, as does your front cab heater. It does not in any way connect to or interface with your fresh water tank.

[skloon]

Okay so I have mostly figured this out, if I fill with the pressure fitting it only fills the rear tank, if I use the hose/bucket filler it fills the front tank- next year I will see if the front tank fills the rear after it fills up- this is all from the factory- the only non factory thing was a loop from the engine powered heater that ran into the hot water tank- I removed that as it was leaking and I had to replace the tank

[Rickf1985]

Damn! how much water can you carry?!!! And all behind the rear axle? It looks to me like you have around 100 plus gallons there? 900 plus lbs.!! That is not good planning. I doubt the tanks are connected or the front one would fill from the pressure fill tank.

[skloon]

The manual shows 40 some gallons, the non pressure tank is connected to the pressure tank top to bottom, so once the front fills then the rear- all this looks factory as there is carpet under them under some really thick clear vinyl-

[CapnDirk]

I'd be curious as to the capacity as well.  Might measure the length, width, and height and convert cubic inch to gallon.

[Rickf1985]

That rear tank may be 40 gallon but I think the front is bigger. I agree, measure it. I am not so sure about the factory either. I think it may have been added after the fact, maybe by the dealer. The fill hose just laying there with no supports is kind of a givaway. The carpet and plastic is under everything in these things, it is the first thing to go in and then they cut the plastic out right before it is sold.

[CapnDirk]

As Rick pointed out, that is a lot of weight for the factory to have considered putting behind the axle.