Gray Water Tank and Winterized Bus Build - inside or under?

[Green Machine]

Hi all,

Still in the research phase of my proposed build, trying to learn more of the details of what I will be looking to do.

I am planning a build for full-time use, will look to follow the good weather for at least a few years of life but want to leave options open. I've family in New England and the more long term possibility would be to purchase property, park the bus and live from it while building a house. So I'd like to plan for a setup that can manage a full Maine winter, with temperatures into the single digits and negatives being a regular thing.

Insulation (lots) and heating are other big areas I've been reading up on, and I've learned that keeping your plumbing internal to the heated space of the bus (and not underneath) is essential for keeping things from freezing during the winter. Makes sense, no questions their. I am just wondering where people place their gray water tanks in a more winterized build?

Thinking that placing the gray water underneath the bus is fine as it doesn't matter too much whether its contents freeze (unless you of course need to empty out the tank...), and read some mention of flushing with some antifreeze when you "open the traps" to just prevent this from freezing (believe I understand what that references, but still new to this subject matter!).

Appreciate any thoughts on the matter, whether first hand experience with such a setup or general knowledge. Thanks!

[Gkozz]

Hi
I see no reply
I have the same question
If you found anything on this let me know
Thx

[PNW_Steve]

I helped a gent here with his conversion that was intended for cold weather living.

We surrounded the tank with 1-1/2" closed cell foam board and installed a tank heater.

Myself, I have tried to avoid really cold weather. When I couldn't avoid it, I would dump RV/boat antifreeze into the tank. It is intended for winterizing your fresh water system. Non toxic.

I once had my sink traps and toilet freeze but my tanks didn't.......

[o1marc]

Put antifreeze in the gray tank.

[Green Machine]

Originally Posted by PNW_Steve

I helped a gent here with his conversion that was intended for cold weather living.

We surrounded the tank with 1-1/2" closed cell foam board and installed a tank heater.

Interesting! So this was installed underneath the bus still? I hadn't considered insulation/heating of an underside tank.

Was this just for the gray water tank, or was this done with the clean water as well? Any recollection what temperature range/part of the country this was intended for?

I definitely like the possibilities of an insulated/heated tank underneath the bus! Very much a preference to keep the bulky tanks underneath if at all possible, not eat up the interior space. I could initially install the tank(s) under the bus without any of these extras and avoid the cold weather while in a more active travel period of skoolie life and later retrofit underneath the bus to insulate/heat the tanks once I'm planning to full-time in a colder part of the country. This sounds a lot more feasible to retrofit so hoping it is the case. I'd imagine it would be virtually impossible to relocate the tank(s) from underneath to inside without a significant rebuild of interior layout!

Thanks for the input!

[Green Machine]

Originally Posted by o1marc

Put antifreeze in the gray tank.

I am glad to be learning about this option, hadn't known this was possible (and that there was non-toxic anti-freeze intended for this purpose!).

Thank you!

[Ronnie]

It would take a lot of antifreeze in single digit temps. Plus each time you drain there goes the antifreeze. This is assuming you are living in it and therefore always haveing more grey water enter it.

[Mark_In_MA]

Either keep the tank inside, or you have to keep it warm. Remember, you only need to keep the tank above freezing - 34-36 degrees should do it,


There are a couple ways to keep the tank warm :


-I'm pretty sure there are commercial heaters built for this very purpose that just get screwed into the tank, and then just need to be plugged in. Some might need a hole drilled in the side of the tank, I'm not sure.

-There's "heat tape", which is a thin wire (with tape) that you wrap around the pipes (and/or tank), and when you plug it in, it heats up. (Some have a built in thermostat.) This is usually for regular homes basements, or homes with an unheated crawlspace underneath. (Don't confuse the stuff for plumbing with the stuff for melting ice dams on the roof,)



-I've seen some people use a timer/thermostat, 100-watt light bulb (incandescent), and lots of insulation.

[o1marc]

Originally Posted by Green Machine

I am glad to be learning about this option, hadn't know this was possible (and that there was non-toxic anti-freeze intended for this purpose!).

Thank you!

Why does it need to be non toxic, are you drinking from your gray tank?

[Green Machine]

Originally Posted by Ronnie

It would take a lot of antifreeze in single digit temps. Plus each time you drain there goes the antifreeze. This is assuming you are living in it and therefore always haveing more grey water enter it.

Yeah, how much antifreeze you would go through did come to mind if the scenario is full-time winter living. Currently I've no idea of the cost of the stuff, how much would be needed per tank full, and what that would all add up to!

The electrical heating options coupled with insulation might be the best overall, need to look into this more!

[Green Machine]

Originally Posted by o1marc

Why does it need to be non toxic, are you drinking from your gray tank?

Hah! Not planning to!

I suppose I was thinking in terms of something that is environmentally friendly enough to be flushed out with the tank, so "non-toxic" wouldn't quite be the appropriate term here.

[Green Machine]

Originally Posted by Mark_In_MA

Either keep the tank inside, or you have to keep it warm. Remember, you only need to keep the tank above freezing - 34-36 degrees should do it,


There are a couple ways to keep the tank warm :

-I'm pretty sure there are commercial heaters built for this very purpose that just get screwed into the tank, and then just need to be plugged in. Some might need a hole drilled in the side of the tank, I'm not sure.

-There's "heat tape", which is a thin wire (with tape) that you wrap around the pipes (and/or tank), and when you plug it in, it heats up. (Some have a built in thermostat.) This is usually for regular homes basements, or homes with an unheated crawlspace underneath. (Don't confuse the stuff for plumbing with the stuff for melting ice dams on the roof,)

-I've seen some people use a timer/thermostat, 100-watt light bulb (incandescent), and lots of insulation.

This is all very helpful to learn, I'll have to look more into builds that have used options similar to these!

[Sleddgracer]

Originally Posted by o1marc

Why does it need to be non toxic, are you drinking from your gray tank?

not drinking from it, but the tank gets dumped at some point and you wouldn't want to poison the environment with regular antifreeze

[BlackJohn]

Be more concerned about the dump valve than the tank contents. If it is frozen shut and you force it, it is not going to close easily or properly.Then you have a mess whether gray or black tank, one you will wish you never bothered to try opening.
Route the heat of the exhaust onto the tanks does wonders traveling or idling. No reason your exhaust can't be piped in that fashion to use waste heat efficiently.
When you are driving those tanks will be sloshing around and not freezing solid. It is when you sit for extended periods you will have troubles in extreme cold, below 20f. Any usage of water that gets drained into the tank creates some movement which works against freezing solid.



John

[PNW_Steve]

My plan, to avoid frozen plumbing, take three components.

A tank of diesel

Ignition key

Compass to point me South......

[Sleddgracer]

two of the old trailers here have a heat collector box in the storage area with the grey and black water tanks, plumbed with hoses to the piping that distributes the heat from one part of the trailer to another - simply connecting a flex hose to a fitting on the collector box reroutes some heat into the insulated bay where the grey and black water tanks are kept - I think routing the exhaust so it warms the tanks, use RV antifreeze in the holding tanks, coupled with heat from the propane furnace should do a pretty good job of keeping things 'moving' in all but the most fridged weather - also plan to have a small wood burning stove in our bus conversion - our plans are to head where -35 is common

[Green Machine]

Originally Posted by PNW_Steve

My plan, to avoid frozen plumbing, take three components.

A tank of diesel

Ignition key

Compass to point me South......

Definitely the simplest option!

[family wagon]

Fresh water tank could be placed inside to keep it warm, or it too could be insulated and heated. I'm thinking I may just plumb a valve and tube so that water coming out of the water heater can be directed back into the fresh water tank.

My waste tanks will be insulated with foam board much like what PNW_Steve described. The jury is still out trying to decide whether that'll be electric heat, or whether to place loops of water pipe under the waste tanks. The latter would work just as for the fresh water: out of the water heater, through a valve, loop around under the waste tanks, discharge back into the fresh water tank. Heat would transfer from the water pipe into the waste tank.

Both hyrdonic approaches require some thought. Because they're part of the potable water system I don't want to have water stagnating in those pipes for long periods of time. It might be important to flush cold water through them regularly, or to design so that they drain automatically when the heating cycle finishes.

[Green Machine]

Originally Posted by family wagon

Fresh water tank could be placed inside to keep it warm, or it too could be insulated and heated. I'm thinking I may just plumb a valve and tube so that water coming out of the water heater can be directed back into the fresh water tank.

My waste tanks will be insulated with foam board much like what PNW_Steve described. The jury is still out trying to decide whether that'll be electric heat, or whether to place loops of water pipe under the waste tanks. The latter would work just as for the fresh water: out of the water heater, through a valve, loop around under the waste tanks, discharge back into the fresh water tank. Heat would transfer from the water pipe into the waste tank.

Both hyrdonic approaches require some thought. Because they're part of the potable water system I don't want to have water stagnating in those pipes for long periods of time. It might be important to flush cold water through them regularly, or to design so that they drain automatically when the heating cycle finishes.

Interesting, that is a whole other option to consider!

There are certainly no shortage of options out there for addressing the cold weather concerns for water tanks, so on my end it will largely come down to what foreseeable scenarios I'll be putting my build through. Initially I want a build focused upon contract work/travel and so can avoid the worst weather, but I also don't want to completely "paint myself into a corner" and not be able to fairly easily adapt the build later on. With most friends and family centered in New England, I know I'll be getting below freezing at some point!

I think I am leaning towards having both tanks underneath the bus and when the time comes to prep for more extended cold weather periods, I can retrofit insulation and electric heating around the tanks. To build from the get-go with the tanks underneath (and not taking up any interior space) while still leaving the option open for later protection against freezing is my aim.

Just don't want to "paint myself into a corner" and later regret any design choices that can't easily be modified/improved on!

[Doktari]

No cold feet for me. If it was me I’d build the entire floor heated hydronically and put a loop on the outside tanks. I’d keep it a separate system from the domestic water. I’d have antifreeze in the hydronic system so I don’t have to drain it every time I leave it somewhere. I’m standing on my diy hydronic floor presently. It also uses much less propane and electricity than the furnace.
Using domestic water for hydronic heating works in some designs. But getting all the water out of the coils for storage is dicey. Compressed air might blow it all out. My first one froze and cracked so I rebuilt it all better with antifreeze. Use DC pumps to minimize the power load.
I would do several layers of insulation. 2” closed cell foam covered by reflective material. 3/4” wood or metal battens creates a gap between the paneling and reflective layer. The reflective works a lot better with a gap.
It’s a giant cooler on wheels.