Fellow Campers
I have completed the next phase in my “extended season” enclosed tank project. This past weekend we gave it a “dry run” to actually see what temps the enclosed space reached when it was cold out side and we have no water in the camper.
First let me bring you up to date on the project events and then the final outcome.
From what I have attempted to find out, this “extended season” feature on my camper is something Sunline did on special request “I think”. The newer Sunline fiver’s have it I think as Std. I saw HappyCampers 5’er at the M & G and his was all closed up. But this is the 1st Sunline TT I have seen with this package other then maybe the special one Karl Kerns had made up. There may well be others out there, just I have not been able to find it in a Sunline.
The TT was at least made with the tank and dumps valves in the right configuration for this “extended season” package, however the amount of holes to the outside environment where still too many for me to feel comfortable in trying this.
Here is what I have come up with.
First off I had to fix my gray tank dump valve setup so I can lubricate the slider valve with Silicone to keep the O-rings from tearing themselves up. And once buried under this cover I had no way to even get to them so I expanded on the idea I use on the manin black tank valve. I added a silicone blow pipe.
Drilled and taped a 1/4” NPT port in the side of the fittings and screwed in a push lock style air line fitting and polyethylene tubing. This is positioned so that naturally not a lot if any water enter the tube. And even if it did I took care of that too.
Then to route the other end of the hose to the dump pipe
Then I drill and taped another 1/4” NPT port by the dump pipe so this is an enclosed tube to the drain system and outside the compartment so I can get to it with the silicone and blow it out for freeze protection.
Now to do the silicone treatment, I unhook the tube, spray in the pipe, then use compressed air to blow it up into the slider valve. I work the valve a few times, spray some more then stick the hose back on. Works good.
I do a similar thing with the main black tank valve just I use a piece of removable tubing I shove up in the dump pipe and spray it with.
The next upgrade was the fresh tank suction port and drain valve. This is what was there to start with. The fresh tank suction port was in the side of the tank which sucks in air bubbles when there is still over 1” of water left and that darn little itty bitty drain hose that takes over an hour to drain the fresh tank when sanitizing the system.
The drain hose would freeze, in my opinion, and it had to go anyway for capacity reasons. I installed a frost free drain spout to get the shutoff inside the compartment and I converted the suction port to the bottom low point of the tank so I can draw water down to the last quart before the pump looses prime. I did this same upgrade on my prior T2499. The forst free spout is the older non anti siphon one so gravity will drain the water out. It was about $10 at Menards, an import.
With the cover on. I cap off the drain spout to keep road dirt out.
Next was the fresh tank bottom. I raised it up to get some drain height, get the low point sump in the tank up higher, get the tank bottom away from the cover with some more insulation, and more so to keep the tank bottom away from the metal strapping. Those tank base bars being so close to the tank have sent accelerated rusting from tank condensation on my T2499 prior to repainting them. Here I can help keep the tank more isolated from sweating in the first place and add a level of insulation. By lifting the tank 1” I did have to deal with the brackets that keep the tank from sliding left to right. I did not take good pics of those brackets but it is not much more then 1/4” flat bar bolted in to keep the tank in place. Sunline used a thin piece of aluminum angle to hold the tank in place. Actually the alum anlge and my 1/4" bar does have parts of it showing in this pic
I also added a remote temperature sensor in the compartment so I can tell what is going on down there. No where could I find anyone to tell me what these enclosed tank type options are good for in temperature on any brand TT so I had to prove it to myself. More on this later but here is the sensor
Then came making the insulation package better. I found at Lowes
http://www.reflectixinc.com/ Reflectix. Here is the Lowes link
Reflectix at Lowes
And this is alum foil bonded to 2 layers of bubble wrap. It can hold up to moisture and it really helps reflect heat. I lined the plastic corrugated bottom cover with this. As I knelt on it putting it on the cover, I could fell my body heat almost immediately insulated verse just kneeling on the black plastic sheet.
Here it is sandwiched up against the TT bottom. I may yet make an edging strip to go around this to keep road stuff from reaching that edge, but no other TT maker does that and the road dirt really does not seem to get up to this area much. For now that is a spring project.
I had to also enclosed the dump pipe with 2” foam board as Sunline left this wide open. Why, I really do not know but leaving those 2 large triangle holes open did not add up to me to keep cold out. I will in the future put a thin alum flashing strip over this area and paint it.
I also used a can of “Stuff” gap and crack filler spray foam insulation to seal up the cracks in the enclosure or where ever large holes where. I still need to trim the globs with a knife and paint them black once the weather allows. The enclosure is not 100% air tight, there are still air gap looses, I would estimate it is 98% closed up. So any little moisture vapor can still escape if there is any.
Next was the test and last weekend provided a perfect test. We camped, dry, and the Night temps dropped to 11 deg F. Burr… I jury rigged the Cyberdyne 12 volt temp gage so I can view it inside. I will later mount it in this storage area by the water pump as that is the power feed I tapped into. This meter also has hi and lo memory recall so I could find the highest and lowest it ever went.
Here it is just giving a reading.
Now to the data: I was happy with the results.
Outside air temp: 11 deg F
Camper inside temp: 68 F (Hunter digital furnace T stat set to this)
Lowest tank compartment over night: 40 F
Highest tank compartment over night: 78 F
Tank compartment temp in middle of afternoon before I turned on furnace: 41F, (outside = 30F)
The radiant heat off the furnace ducts shocked me that it went so high.
Seeing temp in the 60’s and 70’s was unexpected. And seeing it only get down to 40F made me a happy camper with it being 11F outside….
I did not have any radiant heat from gray water from dish washing/shower to add to the space so I do not know yet what that will gain. And I know there are still fine holes in the compartment where heat will leak out of plus the lack of very tight insulation. But I know feel I have a working solution that will give me “extended season” and not have to worrying I’m going to break a tank. When we winter camp, it needs to get above freezing at least during the day and at night it can go into the single digits and for me this is low enough.
I will have to fill up fresh water at the camp ground or do test of the space for heat loose from towing. Have not done that yet. Heat at home before towing, turn furnace off, then tow, then get to camp, read temps and see what I have. However most of our winter camping are in the 1 1/2 hours away from home or less and my fresh tank should not freeze from a 60 degree water fill temp in that short a time or it is way to cold for us to go camping anyway….
Hope this helps some others. I will report more as I learn it.
Happy winter camping
John
.): 
Maybe, They would not have a road vibration issue so much as the ordinary light bulb. Just run a 10-foot set around the tank area with air on all sides of it. 
) I would have thought the jam nut had fallen off. Thanks for the size of the nut John, now I can fix it without two trips under the trailer 
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