Proheat system - specifics, parts, sizing?

[bobofthenorth]

We have an X45 Proheat.  We had some serious "issues" with it a few years ago.  Thanks to Chris Wilson from this board (Chris the GM Bus Guy) it has performed flawlessly for 2 years now.  While Proheats and Webastos are similar in that they both burn diesel fuel to make heat, the similarity ends there.  If you end up with a Proheat take the time to do as Bob Belter has suggested, download the excellent online troubleshooting manuals and read them until you understand them.  I need to pay forward the assistance that Chris gave me so don't hesitate to phone me.  I know pretty well every mistake you can make in servicing a Proheat.

I should add that I have a good friend who runs trucks into the north on oilfield moves.  He has both Webastos and Proheats in his fleet but when I asked him how to fix my Proheat he said "dunno - we've never had one apart - ask me about Webastos". 

[JackConrad]

I personally don't know why everyone wants a Proheat type heating system.  They're complicated, require maintenance, are expensive, have numerous hoses and fittings that can fail taking out your entire heating system, etc.  And at a cost of $6-10,000.00!?
TomC

Hmmm, I paid $450 for my used ProHeat 45,000 BTU unit.  $100 to rebuild the circulating pump and about  $3-400 for heat exchangers, hose, clamps, etc.  We have used it for 3 years with no problems, although I will probably change the fuel filter this year. Our system is a basic system with a single loop that heats the inside of the coach and the rear (plumbing) bay as well as an additional heat exchanger that can be used to preheat the 8
v71.  Jack

[daveola]

Okay, I've created a diagram for the system I think I want to build.  I haven't used a heat exchanger to isolate the engine coolant, but I'm not actually planning on using the Proheat to warm the engine, I'm planning on using it as an alternate heater/preheater for the veggie oil.  Because of this, the veggie oil coolant will either be connected to the engine or the Proheat coolant, but not both.  This seems that it would greatly minimize the chances of a Proheat coolant leak causing problems with the engine coolant.

Here's the full diagram:



But that's hard to read - you can see the full-size image here:
http://bus.getdave.com/Album/Heating/Diagram.gif

And here's the info I've written up explaining it:

Provides heat for:

   1. Bus interior
   2. Drivers seat
   3. WVO heating
   4. Hot water

    * valves Manual to start, but hopefully solenoids at some point. WVO valves are two-way (selectors) and interior valves are one-way (on-off)
    * Thermostats (t-stat in diagram) - wired in multiple to turn on Proheat and to open valves when I convert to solenoids.
    * Hot water - I might eventually add a tank with a heat exchanger to store small amounts of hot water (perhaps with a small 120V element) so that I don't have to turn on the furnace to do things like wash a few dishes. Until then I'll just control the hot water manually.

Thoughts?

[NeoplanAN440]

Okay, I've created a diagram for the system I think I want to build.  I haven't used a heat exchanger to isolate the engine coolant, but I'm not actually planning on using the Proheat to warm the engine, I'm planning on using it as an alternate heater/preheater for the veggie oil.

good ideas!!

i wanted a heat exchanger first also,for the same reasons you have.
after setting up my system for the house,i changed my mind on the bus and went with only one coolant system.
you have to understand that every heatexchanger means losses and also has to be sized right to do the job.
then you need more pumps,second coolant system needs an expansion tank etc....

on the other side,you want to use your engine coolant heat to be used while driving for heat and wvo.
every valve,heat exchanger connection is a point where you can get leaks.
then you need to balance the flow.to many systems in parallel and maybe one wont perform good enough.

in the summer your cabin heaters are off ,but still you need all the heat for wvo.

the only problem with coolant leaks on my wvo systems,that i had on my trucks is mostly with the hose in hose fuel line to the tank.after lots of test i found that aluminum is the only way to go for the line inside the 3/4 inch heater hose.on cooper i had the wvo reacting with it after sitting for long times.problem is that the brass fittings and the aluminum line tend to work over time and like to leak.if they are monted where you cant see it,that can be a problem.

that why i went with the surge tank on the fuel system for the bus.so its enough that i bundled the transfer lines from the main tank to the outside of the heater liners to the front heater.
this way (surge tank)i also dont have to heat the whole main tank to coolant temp.on my trucks i found a lot of condensation water in the tanks,if i used them only for short trips.do to the heating and cooling of the wvo.

as for coolant leaks.i trust my low level warning and always (with the detroit)i have an eye on the temp gauge.

thats my way,less parts less trouble.

if you are interested in how i set up my fuel system,i can try to get pics and explain it better!


im still working on my english (even after so many years here now) and fighting with my computer skills,as i wanted to set up a site with the story of the bus and my other wvo and solar house systems.

but thats when......

[daveola]

So, I've got a Proheat (30kBTU) to cleanup and install.

I was planning on going with simple baseboard heaters, but it looks like it'll take the length of the bus (one side) and about $400 to get just over 20kBTUs of heat.

So I'm reconsidering using some 24V or 120V fan powered heat exchangers - the power consumption isn't much of a problem because I have a hefty electrical system.  Any suggestions on which heat exchangers to look at?  I'm somewhat tempted to build my own using car heater cores and 24V fans like gumpydog does on his site...

[JackConrad]

So I'm reconsidering using some 24V or 120V fan powered heat exchangers - the power consumption isn't much of a problem because I have a hefty electrical system.  Any suggestions on which heat exchangers to look at?  I'm somewhat tempted to build my own using car heater cores and 24V fans like gumpydog does on his site...

A friend of mine did that. He built a small box from 1/2" plywood that just fit the heater core from a Ford pick-up and installed a small muffin fan in the box.  He used several of these in his 4104.  This was after I went ahead and purchased a new ProLine heater exchanger with fan on Ebay. Some times, I need to think more outside the box, LOL.  Jack

[daveola]

So - if I run my proheat when I just need DHW, and I don't need cabin heat or preheating, then there will be a very small amount of coolant in the system (the coolant in the ProHeat, the coolant in the hosing and the coolant in the heat exchanger).

It seems that would make the furnace cycle quickly, since it has very little coolant to heat up.  I'm thinking about adding a tank on the return that will help add some thermal mass.  Is this necessary, and if so, how big, and any thoughts on where to get one?  I'm tempted to get a gas tank from an auto junkyard, clean it out and weld some fittings on it, though that'll eventually have rust problems.

I'll have an expansion tank, but since coolant doesn't actually flow through the tank it seems that won't change the thermal mass of the coolant.

I haven't decided on my final placement for the ProHeat, I suppose I could just put it in the front of the bus and use the 60' of round trip hose to give me more space for coolant.    Need to find some cheap hose that can handle the heat.

[Stormcloud]

I bought a new 5 gal portable air tank, then drilled holes and welded several 3/4" and 1" nipples with ball valves to the tank. That provides more than the minimum coolant capacity recommended for my Webasto.

I can isolate almost any part of the system with the ball valves. It also makes it very easy to add another loop (for engine preheat).

My way..........