Modern AS water tank support question!

[Zybane]

I have a 2016 Classic that I would like to drop all three tank covers to install heat pads underneath. Looking at the tank pans underneath, I am a bit perplexed.

There are hex head bolts going all around the perimeter of each pan. The question being, are the liquid tanks themselves supported/strapped/bolted to the frame independent of the pans, or do the pans themselves support the weight of the tanks?

IE: if I drop a pan, does the tank stay up/attached to the trailer or does the tank drop with the pan? This could make a huge different on how I approach this project.

[dznf0g]

They are not supported by anything other than the pans.

[Zybane]

Oh Geez, that was what I was afraid of. So the tanks must be fully emptied before removing the pan bolts.

That begs the question, what about all the connections? How do you disconnect everything in an area you cannot access to allow the pan to drop? Surely there is not enough slack in PEX tubes and other fittings to allow the pan to drop without damaging other items?

[dznf0g]

It's an ify proposition. Sometimes the plumbing will hold the empty tanks and sometimes it won't. I'd love to add pads in my pans too and probably will....after I retire and have all the time to repair unexpected results of potential damage.

[overlander63]

I've had pretty good success placing a piece of plywood on top of a floor jack, jacking it up until it holds the pan, removing the bolts, then lowering the pan a couple of inches. Then, I slide a nylon strap under the tank, and support the tank with those while I lower the pan.

[dbj216]

I am retired so I have the time. I just dropped my freshwater tank pan to fix a leak in the plumbing lines that run above the tank. I actually replaced them with PEX.

I've had the pan off of all three tanks through the years. They are indeed totally supported by the tank pan. The gray and black waste water tanks did stay in place due to the hose clamps around the vent lines. I did loose the connection between the bath drain piping and the gray tank. Pure luck allowed me to reattach the pipe to the tank and tighten the hose clamp. The vent pipes on the curb side of my trailer would be extreamly difficult to reattach.

There can be no water weight in the tanks if the pans are removed. The tanks themselves weigh in the 25 pound range. They are plastic rotomolded tanks.

I am unsure why we need additional pads around the tanks. Both pans in my trailer have a furnace heat duct directed to them. Both pans are insulated. But I don't travel in the winter with my trailer.

These photos may help you.

David

[Zybane]

Ugg, this does seem like a harder proposition than I first thought.

I am trying to go full electric heat in the winter, so the LP furnace won't be running to force heat down there. I've almost considered putting in an in-line duct heat/blower just to blow hot air down in the belly. But the tank pads seemed like a much more elegant solution.

I thought I would just drop the pans with the tanks being supported by straps like a gas tank, put the head pads on and wire it and put the pans back up and be done with it.

[MelGoddard]

Originally Posted by dznf0g

They are not supported by anything other than the pans.

Which supports the idea that those who design these things , should be CONDEMNED to use them.��

[wcrockett]

Originally Posted by Zybane

Ugg, this does seem like a harder proposition than I first thought.

I am trying to go full electric heat in the winter, so the LP furnace won't be running to force heat down there. I've almost considered putting in an in-line duct heat/blower just to blow hot air down in the belly. But the tank pads seemed like a much more elegant solution.

I thought I would just drop the pans with the tanks being supported by straps like a gas tank, put the head pads on and wire it and put the pans back up and be done with it.

I rigged up a hair dryer to blow warm air down into same air duct the furnace
uses to warm the tanks. It is loud but I only use when we are not in the trailer or if I run out of propane and can not get to place to refill a tank.

[dbj216]

I forgot the toilet flange is actually screwed to the black tank. So it won't fall when the pan is removed.

I now understand your motive for electric heating pads in the tank pans. I think of electric heat being rather inefficient. I had an all electric house back in the 1980s and that thing cost twice to heat than those on natural gas.

But we do use our 1500 watt space heater on cool nights in the Airstream. Works good enough but won't heat the tanks of course.

David

[perryg114]

I expect that room air could be circulated through the furnace tubing that is already there to protect the tanks. How cold will the temperatures be when you might still be camping? I expect the trailer being warm inside would protect the tanks down to the mid 20's.

Perry

[Zybane]

Originally Posted by wcrockett

I rigged up a hair dryer to blow warm air down into same air duct the furnace
uses to warm the tanks. It is loud but I only use when we are not in the trailer or if I run out of propane and can not get to place to refill a tank.

I was thinking about that, but I was curious to know what fire hazards there would be with that method. I don't think those appliances are designed to be used for long periods of time. I am super fire adverse since I have pets inside.

Originally Posted by dbj216

I forgot the toilet flange is actually screwed to the black tank. So it won't fall when the pan is removed.

I now understand your motive for electric heating pads in the tank pans. I think of electric heat being rather inefficient. I had an all electric house back in the 1980s and that thing cost twice to heat than those on natural gas.

But we do use our 1500 watt space heater on cool nights in the Airstream. Works good enough but won't heat the tanks of course.

David

It is rather inefficient, but the campgrounds I stay at the electricity is not metered. From a cost perspective, not using any LPG besides for cooking during the winter is quite substantial. A lot of my electric heat is also radiant (flooring and wall heat strips around windows), leading to more stable/comfortable interior with no noise. Only the electric fireplace up front (1500 watt) has a blower.

Interestingly on another note, I've found out there is no belly pan insulation under the front/spare tire area of the floor in my 2016 Classic. Can feel tons of cold transmission in that area. Will definitely apply some insulation under there above the spare tire.

Originally Posted by perryg114

I expect that room air could be circulated through the furnace tubing that is already there to protect the tanks. How cold will the temperatures be when you might still be camping? I expect the trailer being warm inside would protect the tanks down to the mid 20's.

Perry

So far it's been mid 20's at night and the tanks haven't frozen from what I can tell without the LP furnace running. I think once I get into the teens I will run into problems. I want to be able to go to below 0 F with no worries.

My biggest issue with dropping the tanks is that I have like no access to anything connected to the tanks from the top. Even with the tanks empty, I run a real risk of damaging something just from the weight of the tanks pulling down if I remove the pans. The only thing I could think of is support the pans from below with like an air bladder that I have, lower the pan a few inches and then try and prop/support the tanks from the top/sides before lowing the tank anymore.

Another, much less elegant solution is just to Dremel out square patches of the sheet metal under the tank. That piece of sheet metal would drop down, cut the Styrofoam, apply the tank heater, put the Styrofoam and sheet metal back and seal up the seams. This leaves the wiring exposed though and I would have to route some conduit underneath for the wiring until it goes back up into the trailer floor.

The first option has much more risk than the second I think. Whats your guys thoughts?

[overlander63]

FWIW, we sell SOB trailers that have heated holding tanks, and the "heated tanks" consist of a small 12v heating pad located near the dump valves, between the tank and valve. That's the critical part, so the valve doesn't freeze. It would certainly be easier to attach the heating pads to that location. If you wanted a little more heat retention some of our customers have wrapped insulation around the exposed parts of the drain pipes. You could install the pads, and wrap the pipes with insulation, and try it.
Remember, you only need to keep the contents at 33 degrees, you're not wanting to heat the water.

[slowmover]

Lewster probably has an opinion on tank heaters, and that's always worth pursuing.

I'm in a colder climate now and reviewing these things. I see from a standard RV catalog that there are not only brand choices as to tank heaters, but other electric heating items for tank plumbing runs.

Another SS owner of my acquaintance spent winters inspecting pipelines. Built an aluminum box to fully enclose outlets.


1990 35' Silver Streak
2004 555 Cummins

[Zybane]

Ya I spent like $800 on heating pads for this project. I have dual 110v/12v pads and heat strips for the valves too. Supposedly keeps a totally exposed tank good down to -11 F, so my enclosed area should be good down to the -20's I think with the Styrofoam.

http://www.ultraheat.com/selecting-a-tank-heater

[dbj216]

You have a brand new top of the line Airstream. I'll bet if you called Jackson Center and asked for the Service Center they could advise you on how you can use electricity to keep the water tanks from freezing. Maybe they have done this for other customers. They know how to drop the pans without disturbing the drain and vent connections. They can advise you on the best way.

I'm sure your trailer is a 50 amp rig. That's roughly 5500 watts of power you can use. It might be there isn't enough energy to keep up on a cold Minnesota night.

David