Alternatives to RV heat pads for tanks

[perryg114]

I don't think the tanks would be damaged by water freezing in the tanks unless they are close to full. Ice will move in the direction that it can just like in an ice cube tray. It does not freeze instantly and all of a sudden increase in all dimensions by 9%. You might have problems with valves especially if you have a leaker and the space between the valve and the drain cap gets filled with water. This would also allow the valve body to fill with ice and potentially crack that as well. So I would remove that outside cap or remove the hose connector like mine has. You could put a thermocouple on the ground terminal for the tank sensors. When that got to 32F or below then you need to worry.

Perry

[dznf0g]

Just freeze a milk jug for ACCURATE observation of how water expands when frozen. Do it half full, 1/4 full, and filled full. Draw your own conclusions from you very own observations.

[Skater]

Originally Posted by dznf0g

Just freeze a milk jug for ACCURATE observation of how water expands when frozen. Do it half full, 1/4 full, and filled full. Draw your own conclusions from you very own observations.

Yeah. The damning thing about water is that it doesn't freeze all at once - it freezes outside in. So the top level of the water will freeze first and probably not cause a single problem, but then the layer underneath will be enclosed and put more pressure on the sides of the tank, and so on... Sure, there might be enough room for all of the ice above the level of water in the tank, but the ice won't be able to use that space.

[3 Dog Nite]

Here's how I cheapened out. We lived in our MH in 1 spot for almost 3 years. Before winter came, I would buy a 20' heat tape meant for pipes. I would put about 7 feet in a Z pattern under the grey tank on a piece of regular house insulation. I would hold this up to the bottom of tank with one of those small fish nets used to hold a helmet on a motorcycle. Wrap the drain from the tank to and around the dump valve. Continue back up the Y in the pipe to the black tank. Be sure to get the black tank dump valve too. This would use about 6 feet. repeat the process for the black tank. This didn't look pretty but it worked. The heat tape was on at all times. Of course I would have to remove it when driving, then reinstall. This was easy as MH's tanks aren't behind belly wraps. Maybe with the wraps, you can leave it permanent on a TT.
Ricky

[robwok]

I am building my own tanks out of black 1/4" ABS that has been tacked with Weldon, then heat welded, then solvent welded on top of that inside and out. I planned on using prodex insulation to wrap the tanks except where they touched the underside of the floor.

My tanks are all sloped on the bottom, and very slick inside, so I'm hoping that will help with some issues.

However, I am considering the tank heater option by using 3M adhesive to glue a waterbed heater to the bottom of my tanks, then using the prodex to wrap the outside of the tank heater, then using straps outside that.

I plan on then running the cords up to the inside of the trailer, and tying them in somehow to a single switch. Then, the belly pan goes outside that. I may strap directly to the tank, then use a softer strap to hold on the insulation to keep from having the straps wear through the heating pad.

Rob.

[Skater]

Originally Posted by arodriguez60

have you thought about a waterbed heater? Solid State Low-Watt Blue Magic Softside Waterbed Heater - Walmart.com

Interesting idea. I found this one that's 300 watts and costs $71 on Amazon.com. I don't see why it wouldn't work; just need to adhere it to the bottom of the tank.

[cwf]

So, if I pour a bottle of "crystal clear" into the fresh water tank will that stop me from worrying about it freezing?

Will it drop/ lower the freeze point to say 20 degrees? That would cover most weather here in Central Texas. And, I will have a good start for any drinks....

Just kidding, sorta. Guess drain or pain?

I left the furnace on overnight when we hit freezing. In the morning, I checked the water temp... Very cold... But I neglected to check actual temp. ... Minus the alcohol additive.

Anyway, I wonder if AS has done environmental chamber readying of "freezing" results on the AS design?

[Juliec]

An update on the four years old post would be super timely for my own renovation. How did your installation work? I am interested in the 1) insulation with prodex - does it make a difference; 2) heating pads - are they really a solution?

I need to order two grey water tanks and the size will depend on whether I insulate them or not. I am considering prodex but also, the plain pink closed cell foam.

One quick question... If you were to link the two grey tank together to enlarge the overall grey water capacity, would you put the pipe at the top or the bottom of the side tank? Bottom seems most logical to me but given the discussion about freezing pipes, I am wondering if higher up may be better.

Thanks for your advices.

Julie

[Monza]

Originally Posted by Juliec

An update on the four years old post would be super timely for my own renovation. How did your installation work? I am interested in the 1) insulation with prodex - does it make a difference; 2) heating pads - are they really a solution?

I need to order two grey water tanks and the size will depend on whether I insulate them or not. I am considering prodex but also, the plain pink closed cell foam.

One quick question... If you were to link the two grey tank together to enlarge the overall grey water capacity, would you put the pipe at the top or the bottom of the side tank? Bottom seems most logical to me but given the discussion about freezing pipes, I am wondering if higher up may be better.

Thanks for your advices.

Julie

Connecting the two at the top would mean you could never drain the one with out a drain. Unless you had two drains and I doubt you'd want that.

[KYAirstream]

I finally got around to installing tank heaters, but did so on a new trailer (an Avion). They work great, and the cost to run them isn't bad at all.

Here's a couple links to posts about them.

http://www.aviontrailers.net/viewtopic.php?f=39&t=433

http://www.aviontrailers.net/viewtop...0&p=1946#p1946

[Silverpuller]

Originally Posted by Skater

As someone else said, though, be sure you need them. Our B190 didn't have tank heaters for the gray/black tanks at all, and they were outside, underneath the camper, exposed (the fresh water tank was inside the camper). After multiple trips in freezing weather (with temperatures down to 17 degrees F), only once did we have any sort of problem - and that was that the dump valve froze. It takes a long time for a tank to freeze, and the temperature has to stay below freezing for it to happen, and any sort of movement of the water in the tank is going to slow that process down even further. We probably don't need the heaters for the tanks in our trailer given our usage pattern, but I'd like to have them just to be safe. (I'm making the assumption we'll be camping in cold weather with access to shore power - we just took a trip where that wasn't true, but it also wasn't cold enough to freeze tanks overnight.)

My experience is the same as the writer’s. I lived in my 19’ Hi-Lo Bon Voyage for three years while going to college. This was at Moscow, Idaho, north in the Panhandle. My trailer was on the windward side of a hill, without skirting. The tank hung below the trailer, and NEVER froze. Once, in single digit temps, the slide valve froze shut. My solution: Heat tape wrapped around the valve, associated piping, and drain hose. I even had enough tape left to wrap the fresh water hose (I had been letting the water trickle to prevent freezing). Never had another frozen valve.

[TNauth07]

Has anyone ever thought about putting insulation over tank heater pads? Or should they be uncovered and just on the tank exposed to the cold underbelly?

I am thinking about running the falcon tank heaters, two per tank instead of three and putting thin insulation all over the tanks.

Also going to use heat tape which my neighbor uses as a backup heating source. I am located in Fort Collins Colorado and a fulltime camper.