We embarked upon checking our galley gray tank (35 gallon) on our fifth-wheel after reading about poorly/unsupported holding tanks dropping.
First the good: the holding tank brackets appear sufficient, fore, aft and sideways.
Skipping right to the ugly: The manufacturer says that this model provides "Heated Holding Tanks" and "All-Conditions/Four Seasons Insulation". There is a heating duct to the forward holding tanks (FW70, Gray 67, Black 65), but in examining the galley gray tank I could find no ducting. I used a camera to examine the recess on top of the tank and still could not see any location for a heating duct.
To make matters worse, the "All-Conditions/Four Seasons Insulation" for the galley tank consisted of something that looked like a threadbare, slightly moldy toupee bought at the secondhand outlet, and originally purchased as a gag gift from the dollar store. It might have had an insulation value of R-0.5 The dollar store toupee, all 1/2 inch of it, rested upon the coroplast that is the โfloorโ of the gray tank hold.
The area surrounding the tank is all steel bulkhead walls; the opposite side of those are exposed exterior. There was no insulation in the surrounding space of the tank hold.
Here is a photo showing the tank hold:
Water had obviously sprayed/seeped under the edges of the coroplast and rust was making headway on the flange of the hold bulkheads. I wire brushed and cleaned them with brake cleaner, then refinished all of the problem areas with Rustoleum โProfessionalโ.
For insulation I used 2 inch thick R-10 Dow blue board, and went all of the way around the hold. (The ceiling of the hold is a membrane/wrap material and is the floor of the 5ver.)
Here is a photo of the sidewall insulation.
For the bottom of the tank I used the same Dow product. The insulation for this area is now better by orders of magnitude. We do not use the RV in winter, but I am now more confident that minor overnight freezing will not be problematic.
To close up the coroplast I added stainless steel fender washers to the original screws and Loctite thread locker tape.
I also added 3/4 inch butyl tape around the entire perimeter of the hold flange to enhance the seal from the aforementioned spray and seepage.
Here it is all buttoned up.
The original insulation is a combination of poor design, shoddy workmanship, and a strange definition of โFour Seasons Insulationโ
First the good: the holding tank brackets appear sufficient, fore, aft and sideways.
Skipping right to the ugly: The manufacturer says that this model provides "Heated Holding Tanks" and "All-Conditions/Four Seasons Insulation". There is a heating duct to the forward holding tanks (FW70, Gray 67, Black 65), but in examining the galley gray tank I could find no ducting. I used a camera to examine the recess on top of the tank and still could not see any location for a heating duct.
To make matters worse, the "All-Conditions/Four Seasons Insulation" for the galley tank consisted of something that looked like a threadbare, slightly moldy toupee bought at the secondhand outlet, and originally purchased as a gag gift from the dollar store. It might have had an insulation value of R-0.5 The dollar store toupee, all 1/2 inch of it, rested upon the coroplast that is the โfloorโ of the gray tank hold.
The area surrounding the tank is all steel bulkhead walls; the opposite side of those are exposed exterior. There was no insulation in the surrounding space of the tank hold.
Here is a photo showing the tank hold:
Water had obviously sprayed/seeped under the edges of the coroplast and rust was making headway on the flange of the hold bulkheads. I wire brushed and cleaned them with brake cleaner, then refinished all of the problem areas with Rustoleum โProfessionalโ.
For insulation I used 2 inch thick R-10 Dow blue board, and went all of the way around the hold. (The ceiling of the hold is a membrane/wrap material and is the floor of the 5ver.)
Here is a photo of the sidewall insulation.
For the bottom of the tank I used the same Dow product. The insulation for this area is now better by orders of magnitude. We do not use the RV in winter, but I am now more confident that minor overnight freezing will not be problematic.
To close up the coroplast I added stainless steel fender washers to the original screws and Loctite thread locker tape.
I also added 3/4 inch butyl tape around the entire perimeter of the hold flange to enhance the seal from the aforementioned spray and seepage.
Here it is all buttoned up.
The original insulation is a combination of poor design, shoddy workmanship, and a strange definition of โFour Seasons Insulationโ
newman fulltimer wrote:
Wait till you figure that heat duct actually sucks more cold air into the heater than it puts in the belly
I am puzzled how it would do that. The duct is on the outflow side of the heater, and is a branch duct from the main duct/plenum that runs from the heater for the length of the RV.
Here is the holding tank duct:
and here is the main (at the top left of the picture) that is comes from:
