Tank sag,heater pad clearances and front belly upgrade

pnnf

Member
Hello everyone,

I have a very sticky cable gate valve that I need to replace and while inspecting I found out that I have a tank sag issue that I need to fix as well. I spent yesterday taking the plywood off so I could get in there easily and have a good look at everything. I saw a fair amount of surface rust and the encapsulated insulation was wet. So I decided to make a project out of it and do everything at one time. I threw away all the insulation and washed down the framing in the belly. once that was done filled all gaps with spray foam and even above the frame to help stop temperature transfer. I also sprayed rust killer and then painted. Now the belly is ready for new plywood,vapor barrier,"bubble insulation" and encapsulated fiberglass. I am also thinking of putting 2" foam board in and around the I-beam and the spray foam around it as well. Ive delt with frozen pipes and tanks before and just want to do my best to keep the cold out. Im going to replace the old cable valve as soon as it gets delivered and while looking at the valve and the sagging front shower tank I noticed that the sag is kind of bad. Once I put the new plywood in place ( 2 1/2x4x8 sheets instead of the one giant sheet they have ) I plan on using 3 pieces of 2" angle iron to hold the tank up. My question is this... after i put the new plywood back and support the tank with the angle iron it will then raise the tank belly but the heater pad on the bottom will then be in contact with the plywood and bubble wrap. Do the heater pads need clearance or will being in contact burn them out? Also do any of you have any experience with adding extra insulation to the perimeter "walls" of the belly?

Thanks in advance~
 

danemayer

Moderator
Staff member
Hi pnnf,

I've added 4x8 sheets of foam board insulation mid-ships and under the bedroom. Cut to just fit from inside of frame to inside of frame. You can slip it into place on one side and flex to get it into the other side. The frame will hold it in place. I used a roll of attic insulation taped to the top side of the foam board for additional insulation.

On ours, around the gray #1 tank, there wasn't much space between bottom of tank and coroplast, so I couldn't do the same under that tank. I think I tucked some of the attic insulation around the tank.

I vaguely recall a conversation with Annod Industries customer support about heat on the back of the tank heating pad. I think it's not a problem, but my recollection is a little fuzzy. The most important thing to know about the heating pads is that there must be some water in the tank where the pad contacts tank so that heat is dissipated. I burned holes in gray #1 by running with the valve open one winter. I would think if the heat is dissipated, contact with stuff on the backside is a minimal problem.

To protect the water system, you should consider adding heat tape and insulation to water lines. Before I did that, my kitchen pex lines would freeze at about -10 (F). My gate valves would freeze starting at about -15 (F). To protect the gate valves, consider using foam board and duct tape to build a mini-skirt under your key water system components. Put a ceramic disc heater inside the enclosure. The underbelly will be kept very warm. If it's a smart heater, it won't waste power. Put the heater on a board so if water runs under the trailer, the heater stays dry.

Also, take a look at our owner-written Water Systems Winter Usage Guide to find out more.
 

pnnf

Member
Hi pnnf,

I've added 4x8 sheets of foam board insulation mid-ships and under the bedroom. Cut to just fit from inside of frame to inside of frame. You can slip it into place on one side and flex to get it into the other side. The frame will hold it in place. I used a roll of attic insulation taped to the top side of the foam board for additional insulation.

On ours, around the gray #1 tank, there wasn't much space between bottom of tank and coroplast, so I couldn't do the same under that tank. I think I tucked some of the attic insulation around the tank.

I vaguely recall a conversation with Annod Industries customer support about heat on the back of the tank heating pad. I think it's not a problem, but my recollection is a little fuzzy. The most important thing to know about the heating pads is that there must be some water in the tank where the pad contacts tank so that heat is dissipated. I burned holes in gray #1 by running with the valve open one winter. I would think if the heat is dissipated, contact with stuff on the backside is a minimal problem.

To protect the water system, you should consider adding heat tape and insulation to water lines. Before I did that, my kitchen pex lines would freeze at about -10 (F). My gate valves would freeze starting at about -15 (F). To protect the gate valves, consider using foam board and duct tape to build a mini-skirt under your key water system components. Put a ceramic disc heater inside the enclosure. The underbelly will be kept very warm. If it's a smart heater, it won't waste power. Put the heater on a board so if water runs under the trailer, the heater stays dry.

Also, take a look at our owner-written Water Systems Winter Usage Guide to find out more.

Thank you very much for the reply. I as well will not be able to do insulation between the tank bottom and coroplast/bubble wrap. I was thinking i may be able to double up on the bubble wrap layer instead and with the tank pad it should be sufficient. After sealing up the openings, adding new insulation and then 2" foam board on the perimeter it should be ok. I just didnt want to cause a fire by having the tank pad in contact with the plastic bubble lining. I understand about the water level and thank you for the info.

I will be ordering elbow and gate valve heaters soon just in case there is a problem. everything is enclosed and should be ok . The furnace running 24/7 in the winter keeps a good supply of heat to the bellies. I am stationary and have a 100 gallon propane tank so running out of propane wont be an issue for me. All of my pex lines are in a mid belly well above the tank bellies and are next to the furnace. it stays pretty warm in there and im going to add a couple closeable vents to regulate the temp there as well. Im thinking a few wireless thermometers to monitor the temperature might be a good idea as well.

As long as I dont have to worry about a fire or burning out the pad its self the only other thing i worry about is water...condensation. Have you noticed any problem with condensation since you put up the foam board? ive heard foam boards can cause and trap condensation. im thinking if the foam is tight and thick enough the warm and cold temps wont have a chance to meet on the steal i beam and condense. I still have the rest of this 40' behemoth to do and i guess you could say this front belly is the learning curve lol i could see the other two tanks and they are sagging just as bad so Im looking at more of the same back there when im done up front.

Thanks very much for the help,
safe travels~
 

danemayer

Moderator
Staff member
We wintered in Breckenridge, CO and had to use humidifiers because it's so dry there. The only condensation was where the mattress contacted the exterior slide walls. Leave an air gap at the head of the bed to allow air flow. If you have a problem on the side walls of the slide where the mattress contacts, you'll need air flow there as well. I took shallow cooking tins from Walmart and drilled holes around the sides, then slid it between mattress and wall.

I also installed gate valve heaters. You can't run them for more than 10 or 15 minutes before overheating the valve assembly. I found them to be useless at thawing a frozen valve. And since you can't have them run continuously, you can't prevent freezing. Probably similar problem with elbow heaters. I'd say save your money.

The furnace heating to the underbelly is through a 2" duct that maybe gives you 10 degrees above ambient outside temperature. At 20 (F) outside, the underbelly will probably be at 30 (F). And that's if the thermostat is set around 70.

A 100 gallon propane tank will keep you going for a few weeks; maybe a month, depending on how cold it gets, how much heat transfers through the windows, and thermostat setting. Of course, if you meant 100 lb. tank, that's good for about a week or so in cold weather.

I'd also suggest you make sure your water heater runs on both gas and electric. If electric operation fails, you'll still be able to use the propane side (at least on a Suburban). And you may want to invest in a control board for the furnace. Suburban has a replacement board that can be used in either the SF-42 furnace or the SW-10/12 water heater. Suburban pn 521099, about $82 on Amazon. If the control board fails, it'll be inconvenient to be without a furnace for several days.
 

pnnf

Member
We wintered in Breckenridge, CO and had to use humidifiers because it's so dry there. The only condensation was where the mattress contacted the exterior slide walls. Leave an air gap at the head of the bed to allow air flow. If you have a problem on the side walls of the slide where the mattress contacts, you'll need air flow there as well. I took shallow cooking tins from Walmart and drilled holes around the sides, then slid it between mattress and wall.

I also installed gate valve heaters. You can't run them for more than 10 or 15 minutes before overheating the valve assembly. I found them to be useless at thawing a frozen valve. And since you can't have them run continuously, you can't prevent freezing. Probably similar problem with elbow heaters. I'd say save your money.

The furnace heating to the underbelly is through a 2" duct that maybe gives you 10 degrees above ambient outside temperature. At 20 (F) outside, the underbelly will probably be at 30 (F). And that's if the thermostat is set around 70.

A 100 gallon propane tank will keep you going for a few weeks; maybe a month, depending on how cold it gets, how much heat transfers through the windows, and thermostat setting. Of course, if you meant 100 lb. tank, that's good for about a week or so in cold weather.

I'd also suggest you make sure your water heater runs on both gas and electric. If electric operation fails, you'll still be able to use the propane side (at least on a Suburban). And you may want to invest in a control board for the furnace. Suburban has a replacement board that can be used in either the SF-42 furnace or the SW-10/12 water heater. Suburban pn 521099, about $82 on Amazon. If the control board fails, it'll be inconvenient to be without a furnace for several days.


Thank you for the reply,

I think i may have needed to be a bit more descriptive. I couldnt agree with you more on the humidity issue within the rig. I had to purchase a dehumidifier to keep the humidity within the rig at an expectable level...for me thats 35-40%. Knowing that mold needs 50% or higher i at least keep it below 50% but for me personally i like it less humid. With propane being mostly water, just running the furnace puts a lot of moisture in the air. So for me a dehumidifier is a must have. I dual pane windows and she is insulated well but I still leave all drawers and doors (especially the closet) cracked a bit for air circulation and do keep the mattress away from the wall. It does tend to push itself back to the wall all the time though and i love your idea on the tins. i will definitely use that one,thank you!

The hundred gallon propane tank ( yes, gallons ,not pounds) does like you mentioned. Its last 3-4 weeks when winter gets to settling in. I call when the tank gets to 30% and they come to the site and fill the tank back up. Costs about 150$ a month which im ok with especially considering how often the furnace runs. Thank you for letting me know that the furnace only raises the temp about 10 degrees above ambient. That i did not know. This is why i was going to get thermometers so that i could monitor the temps. Ill still do this but that bit of info is invaluable,thanks. My last 5'er i took the 2" duct out and drilled a 3" hole in its place, bought a 3" 90 and flex duct and ran much more volume of heat to her belly. it worked like a charm. I am thinking of doing the same to my Landmark. especially with the info you gave.

My Landmark is a 2007 and im going to be upgrading the furnace before winter. I hope thats the last project for the season. To my understanding the new replacement is not only more efficient but supplies more airflow as well. This would be good if i expand the ducts to 3" for the basement and/or add a couple more (weather for the basement or the pex lines). I agree that an extra board is a must but im hopeful that a brand new unit will get me through one winter. Next season i can get an extra board and motor to have on hand. The water heater is both gas and electric and I should have mentioned that they are both suburban. I have the 12 gallon water heater and am thinking of getting the 16. Either way, the water heater is getting replaced as well.

I think I going to be ok as far as inside the rig is concerned. I am mainly worried about the belly of my beast. I dont want to do something that is going to cause condensation to collect in the belly. Im putting encapsulated fiberglass back in so the water doesnt soak the fiberglass. I just dont want water settling causing mold, mildew or rust. If I can keep cold air out ant temp transfer down I should be ok. I hear that rigid Styrofoam board will cause moisture to collect. if thats true i guess im going to have to buy a few cases of spray foam and just fill everything in around the frame.

The only other issue for me was clearance for the tank heaters and if laying directly on fiberglass or plastic will cause them to burn out or heaven forbid a fire.

I thank you very much for the help,
Safe travels~
 
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