Bus heating system

[Chaz]

Jerry,
  I kinda thought that may be the case. Dang. But I don't want to put anything on the floor. I do have insulation under my tanks tho.
  Chaz

[TomC]

Just for some comparison on my 40 x 102 transit with big windows, my propane furnace is a 35,000btu that works well down to 25 degrees (the coldest I've been in).  I have two elec water heaters that have 5300btu heating coils each.  So both furnace and water heater is 46,600btu.  Kick in a block and oil pan heater of around 8000btu and your at 54,000btu.  So your 80,000btu burner is huge for what is needed-not a bad thing, just it will be cycling shorter, possibly more though.  Sounds like it will be a nice system.   Good Luck, TomC

[Lee Bradley]

I have a Neoplan Cityliner. It has a LOT of glass and I plan on keeping most of it. 80K should be enough to heat it but cooling it down south should be interesting.

[JohnEd]

Lee,

My plan is to use the hot water from my hot water(hw) heater to freeze proof my fresh water(fw) holding tank.  I will plumb the hw directly to the fw tank through a freeze control relay.  As the temp drops I would meter enough water through the fw tank from the hw heater to maintain a predetermined temp. in the fw.  I will do this whether I have a hydronic system or not.  This keeps me from adding coils to both the hw heater AND the fw tank letting my hw do double duty.

I plan to design my tank arrangement to have the grey and black above my fw so the freeze proof of the fw will serve protect the other two.

The exhaust of the hydronic, and propane heater for that matter, is forced air driven.  That ex pipe can ex straight down.  It can also be plumbed through the other compartments to capture that wasted heat.  The other compartments would only be heated when central heating was called for so they wouldn't overheat.  Have to have an alternate source for hw in the summer though or the compartments would get just to darn snuggly.  That ex should have a slope like a drain and be made of stainless tubing as if you deplete the ex heat you get a LOT of condensation in the pipe.

My thoughts,

John

[captain ron]

I was told I didn't need a tank as I am running mine through my whole system. Engine heat etc.

What is the btu of your furnace? With 80,000 btu I would suspect very short cycles as it is hard to get that much heat out of the unit quickly.
Richard

I have a 45000 btu pro heat

[Lee Bradley]

John,
I am not clear how you plan on heating your FW with the water from the boiler. Can you explain that one more time? Are you talking about mixing boiler HW into the FW?

Thanks,
Lee

[Paso One]

Lee here is a picture ( I hope) of how I heat my fresh water with my webasto or with the engine while driving down the highway.  If I'm running the Webasto  only I have a loop that will circulate thru the engine and this heat exchanger on the side of my water heater.  It will heat the water in the electric water heater when the electricity is not on.

[JohnEd]

Lee,

I'm sure I am niot clear on that.  No, the coolant and fw are not mixed....what a cocktail. 

Generally speaking you have 2 basic methods to heat your fw tank "from the inside".  You can run a coil of copper in the tank and circulate heated coolant OR you can circulate the fw thru your hw heater.  You already have a hw heater so I think it makes sense to use it for as many applications as possible.  I don't want to waste fw running the hw at the faucet till it gets hot.  To avoid that I have a line coming fron the hw line at the faucet thru a push button valve and then returning to the fw tank from whence it came originally.  When I want hw to wash or cook or shower I press the button for a few seconds and the water is hot at the tap and I haven't wasted any.  Simple, huh?

To heat my fw tank I simply ADD a valve to the system that is thermo controled from the fw tank.  When the thermo senses 40 degrees it turns on for 1 minute and purges the hw tank back into the fw tank.  My hw tank is set for 140 degrees and that will burn you if you are careless.  It warms up my fw nicely. It is a highschool physics problem to figure out what the resulting temp of the fw tank will be if you mix 6 gal of 140 degree stuff with 44 gallons of 40 degree stuff.  I don't have the metering system.  I just read the tank temp and purge the hw tank a couple of times in the evening and my tank temp stays up around 50 degrees.

My hw is heated with propane but yours wil be heated with hydonics powered with diesel.  You also can get by without a seperate fw heating system as I have.  My system is in a S&S and my tank is mounted inside but in an unheated space and if it gets down to 20 degrees my tank heads towards 32 and misery.

In a bus I think I would have a propane fired hw heater "and" the one that heats using the engine coolant in conjunction with the hydronic.  I think there is room in a 40 footer.

Hope this helps.

John

[Lee Bradley]

Much clearer. Thank you.
I am planning on a very similar system to purge the cold FW. I am also planning on a propane tankless water while the boiler/engine can provide heat for that system I don't want to run them while running A/C just to have a hot shower.

[TomCat]

Lee, if you want to stay with all propane fuel for your water/heating needs, this unit might do the trick for you...
http://www.precisiontemp.com/pt_rvmd_twintemp2.html

Jay
87 SaftLiner

[Chaz]

Jay,
  looks like a neat little unit, but "proud", aren't they. They are even close to me.
      Chaz

[TomCat]

Yeah Chaz, it's sorta pricey, but PrecisionTemp makes awesome products with a great reputation.

Also if you consider how much a Webasto costs vs the Twin Temp, and then factor in the price of diesel vs propane as fuel, if you used it much, within a year or two you'll probably be about even.

The ideal situation would be to find one on a wrecked S+S for cents on the dollar.

Jay
87 SaftLiner

[Chaz]

The ideal situation would be to find one on a wrecked S+S for cents on the dollar.

  I'm backin on that one!!!!!!!!!!!!!!   But glad to hear they are a good product!
   Chaz