BCM Community

Here I am looking for more help.
I have kept all my water tanks in the rear cargo compartment. I also have my LP hot water tank located there. My intention was to try to utilize the heat generated from it to help to keep my water from freezing. We are doing mostly dry docking.  My problem is that these hot water tanks need to be vented I believe. My rear compartment is isulated and I don't want to allow cold air into it and still have access to the hot water tank. What have most of you done. I am considering re-locating the hot water tank and run a seperate heat source for the water tanks.

Have fun!

What is the feasibility of mounting the water heater remotely, but running a line from the output side of the water heater and feeding it back into your main tank(s)?   Control valve for the flow and rate could be manual or automatic depending on how fancy you wanted to get.

 ;D
No worries
:D
http://www.busconversions.com/bbs/index.php?topic=9559.msg95595#msg95595

http://www.busconversions.com/bbs/index.php?topic=6566.0

Is it a RV type or a house type heater?  Is the tank next to a bay door or in the middle of the bay?  Have seen a section of a bay door vented with a sealed area for the tank.  If you set it up to heat a compartment, will the heat be a problem the rest of the year?

Another consideration is how far it is to the places you want hot water.  It wastes water to run a bunch to get hot water were you need it. BTDT  A central location can help.  I like Sean's method of a recirculating valve to save that water.

Good luck
Don 4107

I have seen a gazillion ways to do this, the creativity of busnuts is unlimited.  I wanted as much bay space as possible so mounted my LP/elec RV type 6 gal water heater under the sink.
With the remote possibility that I might want to go somewhere cold, I enclosed my fresh and black/grey tank in foam and plywood with waterbed type heaters underneath. In 7 years I have never used the heaters!!  Also consider that the black tank will generate some warmth.
I have seen some just install a 120 V outlet in the bay and if needed put a small electric heater in when needed.
                                     HTH Jim

I like the idea of circulating the water back, but then the water pump would run draining the battery bank, and also use exta propane but a remote location and circulating the water would work. A person could mount a seperate circulation pump that is activated by temp. I suppose.

The tank is at the back of the driverside rear compartment abotut 8" from the edge right now. I do have it temp. mounted but can easily move it. Just did this so we could get out using the bus. Have been just cracking the door open when we're parked.

I'm not sure it the water bed heaters would be adequite but a very good idea. It does get vey cold up here! I' thinking I'd  like to be able to use this at -40 degrees.

Thank you guys so much for your imput. Helps to get the gears back in motion in my head.

Have fun! Thanks guys

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I think one key detail in the design involves the extra energy sources (and amounts) you plan to have available while you dry dock.  Besides the LP fuel, we need to look at battery banks, running the generator, and possibly solar.

If there is some way that the water heater and water storage tanks can be close enough to share the heat (but vent the exhaust), that is going to be the most efficient, and require no extra energy.  Pretty much any other concept I can come up with will require some other form of energy to heat the water tanks.

If you take some water out of your water heater and feed it back through your storage tanks, it will likely require some power to move the water around.  Depending on the relative heights of the tanks, you may be able to get gravity to move it one way for you, but a pump will be needed to get it to flow back.  Pumping the water while it is cold will be the easier choice.   Yes, a pump will require electrical power, either battery bank or generator.

Other options involve finding another source of heat to warm the storage tanks.  You could run the bus engine periodically and use the residual heat (inefficient, bad idea).  If your neighbor has a diesel fired Webasto or ProHeat unit laying around in their garage they will give you, that would work nicely. But to go out and buy a new one just to warm your tanks is pricey.

You could use some form of aux electrical heater, such as a water bed heater or forced air space heater.  Any heating device that uses electricity to generate decent BTUs is going to draw significant power.

So basically it comes down to choosing which energy source you want to make available.   

Your understanding exactly what I want to accomplish. Heat with no to little extra energy. I really don't want a draw on the batteries nor run the gen set. I have thought about stripping the rear compartment and installing a system similair to what people are installing in their household/shop floors.

Install a webasto for the bus motor but have lines that circulate through a insulted floor. This would run off of diesel which may be the most effiecient as well as it would spare all other sources of energy. It could also work on valves to control the flow.

In that case I think a remote location for the hot water tank might be good. Such as agaist the back wall of the centre compartment  The lines could be insulated for that short distance and may be alright.
I like the idea of having the hot water tank in the bus but sure don't like the idea of it consumig so much room when we have so much room undernieth.

Do all of you flush mount your hot water tanks with an outside skin or door?

have fun!

I mounted my hot water heater under the sink and through the wall of the bus and use the factory panel/door with the vent.  Works great.  I picked up a waterbed heater at a garage sale for a buck and just put it under my 2 tanks today.  I've already drained the tanks, but I could feel the heater start warming up as soon as I plugged it in.  Drawback is that I'd need to be plugged in to use it or be running the genset.  It may be no big deal when running the genset, I would think that once the water was up to about 70, it would take quite a while for it to cool (100 gal)  and you have to recharge batteries some how.

Glenn

If a Webasto or similar diesel fired unit is within your budget, and you are early enough in your plans to work it into the design, I think it is the top shelf way to go.  It is very efficient and gives you lots of nice options. In addition to keeping the water tanks from freezing, you pre-heat the engine block, or pipe it through flooring or baseboards for general heating. Lastly, since it is diesel, you can carry a huge supply and refill easily.  There will be some electrical drain to pump the water around, but overall it is the way to go.

I think it comes down to investment.  Piping the hot water to recirc through the fresh water tank, involves probably a second pump, a valve, and piping. That is, unless you set up fancy thermostatic controls.  Certainly not the level of investment that the Webasto type system will require.

Nevertheless, if like Glenn, you can find a cheap waterbed heater to throw under your tanks, now is the time to do it.  I've always been big on redundant systems. Or as I frequently say: "I like options. Options are good."

Many of the factory made 120/12 volt tank heaters have a thermostat that kicks the juice on at 34 degrees. Many are 75 watts or better or use a 10 amp 12 volt fuse.

A waterbed heater is designed to heat 300 gallons of water to about 100 degrees in an 8 hour rate of rise anyway so adding a low temp thermostat to turn it on when the bay temps are 34 degrees would work.

I used a pair of 24X24 Inch thermal heating panels ( rubber mat style ) from a surplus store with one under the fresh tank and one under the dual grey/black tank and they worked excellent last winter with temps below 14 degrees. They are rated at 120 watts each. I hooked them in series and that worked great.

I am not so much worried about tanks getting too cold, More like keeping the water lines above freezing. There are heat tapes now available that work for those. I also ran my water hose inside a 1 1/2 inch PVC conduit across the ground and with some minor flow going the hose didn't freeze up.

Always remember to keep the pumps warm even if the lines get icy. PEX will handle some abuse but the plastic pump housings and fittings will not.

Sticky backed heat tapes work on pumps and small items even in the 15 watt @24 volts range. Surplus stores usually have a few of them in some fashion. Or the mainline industrial suppliers may carry them also.

Dave... Brrrr.... It's getting chilly here early this year....

Hi Busshawg,
I think using your bus at -40 degrees is unrealistic, unless, of course, it is in a heated building. We spent a night at Branson, MO, on our way to Texas, when it got down to 4 degrees above and it was not comfortable in the bus. We have a 35,000 BTU gas furnace and had two 1500 watt electric heaters in use. It was still not enough with the original bus insulation and the windows covered with foil covered bubble insulation. If you have urethane foam insulation and window blankets, that would help, but I doubt if you could stay warm at -40 degrees. We have no insulation under most of our floor so steping out of bed with bare feet was a real eye opener. We had another electric heater in the water bay so at least the bathroom floor was warm.
Good luck with your plans, Sam 4106.

The question Sam raises is certainly a valid one.  When I first saw the -40 figure I said a little "Wow" under my breath.  (Of course, since -40F = -40C, there is no need to specify which) 

I've never had the pleasure of being in those sorts of temps.  I have vivid memories of being in -15 and -20F temps and seeing how different things are affected.  I recall driving a car first thing in the morning. There was a wup-wup-wup sound for the first mile or so until the tires warmed up enough to become flexible.  Some vinyl materials become very brittle.  Lots of wierd stuff happens to materials and mechanicals.

No doubt Busshawg has experienced this stuff first hand.  I will try to be polite and not question his sanity for even wanting to dry camp in those conditions in the first place.  Caribou hunting?  Hey, I never understood ice fishermen, either.

If it is not hyjacking this thread too badly, could I poll our northern friends with the question:  "What is the coldest temp you have used your bus (slept overnight)?

LOL guys ! WEC4104 don't worry about my sanity as I know I've already lost it, and Sam I'm thinking your probably right that it is unrealistice however I want to make this bus so I can fire it up in the dead of winter and will spend a couple of days getting to a location that is more humane!! Anyway I guess what the objective is , is to try the best as I can to install a system that will withstand freezing temps.. It does get down to -40 here, but not necessarily that the bus will need to be used in these temps. But I do want a good system so we can fire up in the winter here and head south, I don't mind the winter but it is just way too dam long. We do intend on full timing it eventually. I have heard of people living in these buses full time even up here in the winter but they have installed oil funaces etc. Thank you all for your replies as it sure hs got my wheels spinning. Ideas such as the water bed heaters is something I would have never thought of. I appreciate all of your posts!

Have fun!

In the scenario of firing up the bus and taking a few days to head to warmer climates, the bus would have been winterized before you leave, so you won't have water in it.  Use a block heater to take care of the engine for starting, head south, get water.  Use a heater core and fan from some car tied into the DD/genset to keep the rear bay warm while under way.  For parked scenarios, run a duct from your propane furnace into the bay.  No big deal since it is already insulated.  Just ideas!  Fire away!

Glenn

We did this a long time ago.  Wish I knew where the post was.  Sooooo.

Build your tanks on top of one another.  The bottom is the fresh and the gray and black are each half the capacity of the fresh and they both are a foot longer.  The fresh is the only tank you heat and the heat will migrate to the top two siting on top.  You can heat the fresh by simply piping the hot water back to the fresh an using a valve to control the flow.  I will also have a fresh tank return on all hot water faucets to avoid wasting water getting hot to the faucet.  I rigged a thermostat to the hot water line and let the hot dump water when the fresh tank got to 36 F.  I also had separate hot lines that were taped and insulated to the other lines I was protecting.  here again the hot water came on to heat those areas till the thermo cut out.  That still warm water went back to the fresh also.  I had 120V power for this and my propane heater had a elect element and the outside of the tank was well insulated....no propane use possible in that config.

For the temps you are talking about you will need a spray foam insulated coach and that will have to have fir strips in coroperated in the design and a wall thickness of 2 1/2 inches for R17.5.  Roof will be 3 or 4 inches thick with foam and no ceiling ducts.  The interior ceilings of the bays will have to be 3 inches thick foam and the floor in the coach would be another 2 inches foam board topped with ply.  You need to be able to curtain off the entire drivers area with a thermal curtain as that area has so much metal in it that is heat synced to the outside skin.  I have seen pics of a coach in Montana that had little places under the interior walls that touched metal.  He had little "buds" of frost on the inside walls where they touched.  His walls were sprayfoamed.  I think all this would just be a start.  All holes and fluid penetrations would have to thought thru well.  Windows...double pane and rated for R???? and even at that covered with shrink film.  It can be done, though.  My Winnie would have the temp raised 30 degrees by a single cube heater and with two I was good to 10 degrees F.  Then the propane kicked on for the score.

Good luck here.  You are thinking thru it at the correct stage and many have great advice to save you a ton.

HTH,

John

Excellent advice John, you have definitly given this some thought. Thanks for all of your advice. As long as the bus engine is running a heater core in the rear compartment is a good idea also.

Thanks again
Have fun
Grant

Just you know, I ended up cutting a hole in the drivers side of the bus to install the hot water tank. It is now sitting in our lower kitchen cabinet. Not a popular vote from my wife but this way the tank is vented to the outside as it was designed to be. My concern about this was that I really didn't want to cut through the outer skin and definitly didn't care for cutting the chair rail in the wall as I'm sure it helps with the overall strength of the bus. Oh well it's done and the tank fits well with no risk of these fumes enterning the bus.
Next project will be to ge a wabasto/ proheat installed for heat to the rear comartment etc.

Thanks guys
Have fun

We have a Knut on the board that has "some" Webasto's for sale.  I think it was Frank Allen but I am not sure.  Hope someone can help here if only to shut down a fruitless search.

John