I bought a used Webasto Thermo Top C (17,000 BTU).
6V92TA.
I am installing it inline with the coolant line that goes from the engine to the front defroster. It will preheat the engine, then the generator, then go through a radiator in each baggage bay, to the defroster in the dash, and back to the engine.
Just to confirm what I think is right: which one is the supply line out of the engine? There are 2 lines: one comes out from the back of the engine, the other is T'ed into one of the rad pipes, looking like it returns to the water pump.
So I should T off of the one that comes out from the back of the engine, to go to the Webasto. And the return to the other line, right?
The bus has a propane furnace to heat upstairs. Boondocking overnight on the way South in the winter, first thing we do when we get out of bed is start the generator (propane), and turn on the 2 engine block heaters. By the time we finish breakfast etc, the engine is nice and warm and starts just by showing it the key. The problem is that if it is cold out (20 below is not uncommon in Montana or Idaho), the generator can be hard to start. So I am thinking this Webasto is going to preheat both the main engine and the generator, and the basement.
Anyway, I just want to make sure I tap into the right coolant line out of the engine.
Thanks.
JC
The line that comes out of the engine and heads straight forward is your goal.
Flow in same direction.
Where are you mounting it?
My big one was on the floor of a bay, big pipes were cut and everything went through the webasto on its way forward.
This was to heat the whole interior via an HVAC bypass switch, mobile classroom in its earlier conversion.
If you just have the defroster up there, the smaller pipe shouldn't be a problem.
The engine will get pre-heated when the return flow reaches the block.
Happy coaching!
Buswarrior
Yes there is a line that comes out of the back of the engine and heads forward toward the front of the bus. The other line (the return),T's into one of the pipes for the driver's side radiator.
I am mounting the Webasto driver's side in the engine compartment near the fire wall. I have lots of room there. It is just under the coolant lines that go forward into the bus.
It will be a simple inline system: flow out of the engine, through the Webasto, through the generator, through the bay heating radiators, through the defrosters, then back to the engine.
JC
That ought to keep things toasty JC.. I'm wondering if each "radiator" needs a fan for circulation.?? your bays are large.>>>Dan
Curious why the bay radiator? To keep the wet bay warm while on the road?
Dan, yes I am going to get radiators with fans.
Richard, the baggage tanks don't have any heat in them now, other than the water heater in one, and the propane furnace in the other, which is not much when it is 20 below outside. I have thought about blowing heat in there off the furnace, but it would rob off of upstairs. The hot water off the Webasto can be used for that.
JC
And the radiant heat of the defroster exchanger being warm is going to be noticeable.
For camping use, the driver's heat water valve will continue to regulate. Beware to not snuff out the flow...
Happy coaching!
Buswarrior
with my cat if it is cold out there is not a lot of heat at the dash unless the boiler is on to boost the heat . it sure helps to keep the dash warm . It was not that bad on the 6v92 as it had lots of heat most of the time
dave
Yea Dave, no lack of heat out of a 2 stroke. When I used to look after the hockey team's DL3 with S60, it had a 2020 Webasto that was necessary to keep the engine hot. The S60, like a lot of modern 4 strokes, doesn't heat up until you work it hard on the highway. They commonly come OEM with a coolant heater for that reason.
JC
You are expecting a lot off 17,000 BTU's. Those are made for car heating systems. The correct Webasto would be a 45,000 BTU unit from a DBW 2010.
Quote from: lostagain on November 06, 2019, 07:53:13 AM
I bought a used Webasto Thermo Top C (17,000 BTU).
6V92TA.
I am installing it inline with the coolant line that goes from the engine to the front defroster. It will preheat the engine, then the generator, then go through a radiator in each baggage bay, to the defroster in the dash, and back to the engine.
Just to confirm what I think is right: which one is the supply line out of the engine? There are 2 lines: one comes out from the back of the engine, the other is T'ed into one of the rad pipes, looking like it returns to the water pump.
So I should T off of the one that comes out from the back of the engine, to go to the Webasto. And the return to the other line, right?
The bus has a propane furnace to heat upstairs. Boondocking overnight on the way South in the winter, first thing we do when we get out of bed is start the generator (propane), and turn on the 2 engine block heaters. By the time we finish breakfast etc, the engine is nice and warm and starts just by showing it the key. The problem is that if it is cold out (20 below is not uncommon in Montana or Idaho), the generator can be hard to start. So I am thinking this Webasto is going to preheat both the main engine and the generator, and the basement.
Anyway, I just want to make sure I tap into the right coolant line out of the engine.
Thanks.
JC
I agree with Geoff. 17,000 btu is a bit shy on power. Considering my propane furnace is 40,000btu just to heat the interior...
I don't think he intends to heat the bays as you would the interior of the coach,,, just enough to prevent freezing..
JC,, Are you going to get as far south as Yuma this year.??>>>Dan
Guys read my posts... The Thermo Top C, at 17,000 BTU, is made for transport trucks to preheat the engine, and heat the sleeper overnight. I am only going to preheat the generator and put the left over heat into the bays to prevent the plumbing from freezing. The 6V92 will be at the end of the loop. If it needs more, I run the electric block heaters off the generator.
Dan. We'll be in the SW in Jan, Feb, and maybe March. We'll see you I am sure.
JC
A guy from Alberta knows what a BTU is and how to deploy them
This appears to be about maintaining while operational, not being stone cold in the Arctic.
It doesn't take a nuclear event to start the big engine, or to prevent freeze-up, when you're already warm from the day's drive. Keeping it warm is a lot easier than getting it warm.
Big BTU are needed when you have a big temperature rise desired in a shorter time frame.
Happy coaching!
Buswarrior
I returned home early from a florida trip one year and hit a cold front
- 30 burrrrrrr even with the proheat and the 6v92 working hard on the hills it was cold . had a hard time keeping the front window clear
never again ........ I hope
dave
sleadhead,
When the buses went past you headed for Timmins back in the day...
Gray Coach ordered their MC9 with single pane glass and bifold doors... some accountant thought he was saving money...
The ONR pool drivers hated them.
Loaded, 8V71, auto tranny, everyone was wearing their coats...
So, it isn't just a busnut thing, the seated coaches struggle to stay warm under the right conditions too!
Happy coaching!
Buswarrior
Seems to me the Eiberspacher brand of webasto used in the DL3 is over 80K btu. I'm thinking they didn't go that big because they didn't think they'd ever need it.
Jim
According to JCs post,, he has 17000 BTUs /hr to use,, and six points to heat.. That would be the same as having an 830 WATT light bulb at each point PER HOUR!!.>>>Dan
Not to heat, to keep warm.
And once it settles in, it will run steady, no cycling on and off to wake you up, like a big one does.
Sometimes, less is more.
This is hilarious, a pair of Canadians telling y'all you don't need that much heat.
Happy coaching!
Buswarrior
Working on my basement heating project... A lot of work...
I took the Honda EV6010 generator out of it's enclosure in the bus. The only place I could've tied in to heat the coolant would've been on the rad hoses. It would have only heated the rad, not the block, because the thermostat is closed. I was also concerned about the difference in rad cap pressure between the genny and the bus engine.
Good thing I removed the genny, because I found that the exhaust pipe out the bottom of it was quite rusty, and would've fallen off any time. So I will be building a new exhaust when I put it back in... One thing leads to an other...
So instead, I am installing a heat exchanger inside the genny enclosure. It will draw air out the baggage tank, heat the genny, and push it out back out into the bay. Then an other heat exchanger in the other baggage tank.
I should be done in another day or two.
I'll post about the results...
JC
And I can also confirm from my bench testing that the Webasto will not stay running as long as there is air in the lines. It knows there is no water, and shuts off. Mine is mounted on the floor of the engine compartment, so I think it will have gravity water to it when I fill the system, and be able to push it up the line to purge the air out.
JC
Got done today, other than some finishing touches I'll get to tomorrow.
It took some doing to purge the air out of the lines: the Webasto alone would not do it. I started and ran the Detroit on fast idle for a while until it got hot enough to open the thermostats, and coolant started flowing up and down the lines to the front. ( I had drained all the coolant out of the bus). I still had 3 to 4 gallons of coolant that wouldn't fit in, and the one heater behind the driver's seat with not heat, evidently with an air bubble. The Webasto was working intermittently; it doesn't like air bubbles... Left it overnight, and this morning it had purged itself as it cooled off apparently: good thing. I ran the Webasto for an hour. It would speed up and slow down at first, because of some remaining air bubbles, but soon got steady as they were pushed out, and I was topping up at the surge tank above the squirrel cages. Remember the Webasto Thermo Top C is only 17,000 BTU. It got the whole system to 90F, measured at the thermostat housings. Not really hot, but hot enough for my purpose. The engine is warm to the touch, the generator enclosure is super warm, the baggage tanks are warm enough to protect the plumbing from freezing, and the defrosters and the heater behind the driver's seat are toasty. I think it will work for me as intended. Remember I have a propane furnace to heat the cabin upstairs (40,000 BTU). To heat the whole bus, you would need a bigger Webasto, like a 45,000 BTU. I might want to get to that some day, and remove the furnace, which is physically 5 to 10 times as big as a Webasto in the bay. Would be nice to free up the space. The 2020 heater I had for a while with the Detroit S60 would have everything up to 180F in half an hour.
So anyway, it was a fun project, albeit long and arduous, but I feel great about it. I think I am well prepared now to travel in the middle of winter without worrying about freezing sh*t up, and knowing that the generator will start when I need it. Now I can't wait to boondock in a truck stop at 20 below with a North wind. Well, not really...
JC
I wonder if anyone has contemplated running a copper loop through the air distribution box on a Suburban propane furnace for hot water or generator preheat.
glad it worked out and I hope when I travel south this winter you get all the cold weather you need to test the system so I get the warm weather
dave
Might be better to make that copper loop out of stainless but it should work if the water circulates.
Jim
Could probably add a mini circulation pump to operate when furnace comes on, as long as it didn't restrict flow when off. Maybe add a temp sensor on output side of loop.