| Author | Message | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 96 Registered: 10-2007 Posted From: 206.45.93.160  Rating: N/A |
I have run these unit before but they have been installed in the units for me. I want to install the unit in the rear area where the factory A/C compressor was. My question is can I run my fuel line off of the filter housing for the bus engine? There is a plug on it. I was thinking I would just remove the plug and fit my fuel line from there. Is there too much pressure for the wesbasto at that point? Would the webasto pump pick the fuel up ok from this point?? Thanks | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 97 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
I should also ask is there any 12 volt access at the back of my MC9 to power this unit? and if not what are your suggestions for 12v power back there, I don't really want to use my house batteries but will if neccessary. thanks again | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 620 Registered: 8-2006 Posted From: 74.33.56.77 Rating: N/A |
Grant, the unit needs it's own supply it is never a good idea to tap the engine supply for anything I have a friend that tap the filter for his gen and had problems with both the engine and gen. good luck | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 98 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
Thanks, I guess I'll mount a fuel tank in one of the compartments and it can run my airtops as well. What about 12V power in the rear of the bus, is there anything? | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 621 Registered: 8-2006 Posted From: 74.33.56.77 Rating: N/A |
Grant, I have owned 2 MCI's was told there is one in the rear panel junction box but never had need for it so I never checked it out but best I can remember it was post 55 some of the MCI guys will know for a fact good luck | ||
| Ed Roelle (Ed_roelle)
Registered Member Username: Ed_roelle Post Number: 72 Registered: 3-2005 Posted From: 71.0.165.140 Rating: N/A |
Per the written Webasto specifications, the distance between the fuel tank and engine is too great. I don't remember the number, but it influenced me to locate the Webasto closer. Why don't you want to use your house battery bank? Is it not going to be your house heating system? Ed Roelle Flint, MI | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 99 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
Thanks guys Ed no I have decided to just to get rid of the factory heating system. The webasto air top heaters are a dry sytem and run very effieciantly. The fumes will be minimal as well with the choice of running one or two seperatly. Others that are running them say one unit should heat my bus at approx .2 litres / hr which in my opinion is very cheap. That way I won't have to run the big webasto unit for those mornings where just a little heat is required. Maybe I've been sniffing too much glue from when I installed my interior. I realise that these air tops run about 1700 dollars per unit but I have found a couple of fairly new used ones for 400 a piece. I have had some instruction from a fellow bus nut to build a system where I could run the big webasto through out the factory collant system that looks very appealing however I feel that the airtops are easy to install and work very well. The reason I didn't want to run off of my huse batteries is just to keep this unit seperate. I guess it's just a mind set thing that it is for the engine so I just wanted to keep it powered from the bus batteries. Save all the charge I can on the house batteries for living. I don't quite have a decent sytem for charging my house batteries yet. I have a honda gen set and want t o use it somehow to charge the house batteries. | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 100 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
Thanks guys Glad to hear thwere might be a 12v supply back there. Ed I have decided to get rid of the factory collant sytstem in front of the valves that shut off the coach heat. At this point would be where I would connect my webasto. In place of it I want to install the webasto air tops. Not sure if your familiar with them. From what I've been told they run on very little power and consume about .2 lites of diesel per hour. I would be able to run them independantly of one an other. I'm thinking this might be the most effiecient way to heat the bus. I was just thinking when I start the big webasto there is alway more fumes and it would be harderon fuel. No cold leaks this way. I would install one in the drivers area as well and just tap into the exsiting ducts. Maybe I've been sniffing too much glue from when I did my walls! I did get some real good advice from a fellow bus nut of how to run the large webasto to heat the bus or just which ever one of the items I wanted to heat. However I feel that the airtops will be more efficient. By all means correct me if I'm wrong. As far as the power source. I feel that the webasto is for the bus engine only. Save all the juice I can for the house, especially if I can run a wire from the rear junction box. Not as much wire, less chance of a short etc. I haven't figured out a decent charging system for the house batteries as of yet. I have a honda gen set and I'm not sure if running the gen set will charge the batteries. Hope so but for some reason have my doubts. | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 101 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
sorry for the close to double post | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 697 Registered: 8-2006 Posted From: 12.69.89.106 Rating: N/A |
Grant, A couple of thoughts here, Diesel contains 144,000 BTU per gallon. 3.785 litres per gallon, I think. Thats about 37,000 BTU a litre. .2 litre per hour is less than 7,700 BTU/hour, which isn't squat! Thats also at 100% combustion efficiency, while actual combustion efficiency will be very close to 80%, meaning at .2litre/hour you will get about 6,100 BTU/hr, which isn't worth the time. I'm out of time right now, so I'll chew on you more later. Sorry, George | ||
| Ralph Peters (Ralph_peters)
Registered Member Username: Ralph_peters Post Number: 12 Registered: 12-2008 Posted From: 206.251.9.233 Rating: N/A |
The airtop I have crapped out after 6 weeks of use, webasto had no answers, try this, try that, now today a webasto tech thinks the fan or circuit board problems. Repair starts at $370.00 not considering labor or other parts which it will need???? Yes George is correct on output, and if you use kerosene output is about 2000 less, so if your coach is insulated very well?? Good luck ralph | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1301 Registered: 10-2003 Posted From: 71.58.110.9  Rating: N/A |
Go get two electric heaters that put out comparable btu's ( once you figure out what it is going to be), and try them and see what it'll be like, satisfactory or not. Probably to do it right would require at least three and, don't they make these units with greater output? Of course, you'll have to factor in how much battery drain the system will create. | ||
| joe padberg (Joemc7ab)
Registered Member Username: Joemc7ab Post Number: 329 Registered: 6-2004 Posted From: 66.38.159.33 Rating: N/A |
Grant Consider carefully doing away with your over the road heating. Remember you are in Manitoba, and it gets just as cold as it does here. What happens when you want to go somewhere in January? Unless you are rigging it up for mild climate use only. Joe. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 698 Registered: 8-2006 Posted From: 12.69.89.106 Rating: N/A |
Grant, Johns got one heck of an idea there! A 1500 Watt electric heater will put out 5118 BTU, which is right at the output you are describing at .2 litre/hour. Put it in your bus sitting still, and see what (doesn't) happen. Moving would be much worse... To get a perspective on available engine heat, a bus getting 10 mpg going 60 mph will burn 6 gallons per hour, at 144,000 BTU/gallon, for well over 800,000 BTU/hour. I don't have a clue how much of this goes out the exhaust, but it is considerable. Anyhow, there's several hundred thousand BTU left, which is why buses have big radiators and fans. In the winter, with the thermostats closed, the big rad and fan is your heater, and an output of 80,000 BTU an hour is not out of the realm of reality. Needless to say, after you get the bus warm, the output will be turned way down. My preference is showing also, HTH, G | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1256 Registered: 5-2001 Posted From: 65.74.69.188 Rating: N/A |
Gramt, I think that the cooling system will need to get rid of 250,000 to 300,000 BTU when going down the road before you break the highway speed limit. There is no way that we would dump our bus heating system. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1257 Registered: 5-2001 Posted From: 65.74.69.188 Rating: N/A |
Gramt, I think that the cooling system will need to get rid of 250,000 to 300,000 BTU when going down the road before you break the highway speed limit. There is no way that we would dump our bus heating system. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1477 Registered: 12-2000 Posted From: 76.69.142.53  Rating: N/A |
Hello Grant. You need the pipes to stay intact for the defroster to work. You will FREEZE driving that bus without the stock heat in the dash getting a proper supply of HOT water from the motor, the front of the coach, with it's uncontrollable openings and the heat sink of the front skin in the wind will be VERY uncomfortable, even in above freezing temps. The big trouble with designing heating and air conditioning is the "over capacity" that often gets left out. Yes, you might keep a warm coach warm with only a pair of Airtops...but you'll have a devil of a time getting them to raise the temperature from frozen. Same as horsepower, the more you have, the quicker you get up to speed. The less you have, you wait, or never reach the intended speed. An Airtop or two would be a great choice for taking the chill out wherever one would wear a light coat, but insufficient capacity on their own, in my mind, for a coach that will see freezing and below. If you plumb in the Webasto, use your Airtops, keep your coach blowers, and wire a bypass, you can have your cake and eat it too. My coach blowers can be run without the engine running, just need a healthy 24 volt power source, and the Webasto provides the hot water to make it all work. Block off the outside air intakes to increase efficiency and you have your extra horsepower, and your heat still intact for going down the road? On the power front, as my first priority, I couldn't care less about the house system failing, I want to protect the engine starting batteries, so I can leave! The house being depleted does not render me immobile. When camped, my design goal would be that everything that is intended to run, runs off the house batteries. My batteries come together at the stock coach battery switch. The house batteries have a manual switch in parallel to the coach switch. Either set may power the coach, each has it's own "replenishing source" and may share with the other when connected (The Trace 4024 in the house system, the coach alternator in the other) So, upon arrival, the stock batteries get turned off when camping, the house batteries are left on, and the coach circuits may be used via the house batteries. For instance, plug in to the power pole, the Trace is powered to charge the batteries and I may leave the clearance lights on for decoration in the evening. The various 12/24 volt devices continue to work the same regardless of running or parked, nothing to remember or forget, no restrictions depending on operational mode, no neurotic hand wringing or anal retentive foolishness. All the electrics run through the Trace, so the 120 volt systems work the same seamless way, whether parked, plugged in, generator running, or driving down the highway. Something goes wrong and the batteries go dead? Just pull the other switch on, and start the engine like nothing happened. happy coaching! buswarrior | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 744 Registered: 1-2003 Posted From: 67.142.130.37 Rating: N/A |
I'd like to weigh in here on a couple of points. First, if you have a 24-volt bus, you should get a 24-volt Webasto. They are the same price and availability as the 12-volt model, so why go through the hassle of finding 12-volt power for one? And a Webasto unit will draw enough current at 12 volts that you will definitely need an equalizer, plus any existing 12-volt access at the rear of the coach will likely not be able to support a Webasto unit, and you'll end up having to run heavier gauge wire anyway. On the subject of efficiency, I don't understand your reasoning behind adding the two Airtops. A DBW-2010 is more than enough capacity to heat your whole coach (and, in fact, it's something of a waste to install one just for engine pre-heat). The argument that the Airtops use less fuel is specious -- while a 2010 will use .35 GPG while running, in a properly designed system the boiler will only run part time -- just enough to provide whatever level of heat you are calling for. About the only inefficiency of the 2010 over the Airtops is that some heat will be lost to the environment through the plumbing, which, for us, is a plus -- it keeps our tanks from freezing. In order to avoid wasting domestic heat by heating the engine block unnecessarily, though, you should plumb a separate hydronic loop for the Webasto, and tie them together with a heat exchanger. You would then have to add a small electric circulating pump for engine pre-heating, but another advantage of this method is that you can use cheaper coolant in the hydronic loop (no SCAs), and engine coolant maintenance requires less fluid to be drained. I just can't see spending the $3k+ on the Airtops, when, for that money, you can get all the heat exchangers that you need, and have a more robust and safer system overall. FWIW. -Sean http://OurOdyssey.BlogSpot.com | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 103 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
Well I'm sure glad I mentioned , correct me if I'm wrong, haha . Thanks for all the opinions and info. I did get help to plan for a system to use my webasto unit so it would do everything and which ever I wanted it to do. Judging by your responces that will be the way to go , so that's what I'll do. I guess I'll install it in my water bay as mentioned, makes sense. I'll leave the air tops alone. Another question , what type of heat exchangers are you using. BW mentioned using the exsisting 24 V fans. Would save on heat exchangers as well. I guess that would be very convenient, don't those fans use quite a bit of power. It wouldn't be something I'd be able to leave running day after day would it. Can I install another fan in that comapartment that might be quieter and draw less power? My bus is insulated quite well with spray in. I guess by the sound of it I better check out these Trace units as well. Sound like teh ticket, I am simply just running a 4000 watt inverter off of my house batteries and am at the point of trying to figure out what to do to charge my house batteries. My gen set in the A/C condensor compartment and my house batteries are located in the compartment right behind that on the drivers side as well. So I was just tinking I'd have to fire the get set up to charge them. I'm probably out to lunch here too but I hope you can tolerate my ingorance in this case. I am all ears. | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 745 Registered: 1-2003 Posted From: 67.142.130.22 Rating: N/A |
Grant, I can't answer for how much current the factory heat fans draw, but I would guess a bunch. The over-the-road heat had to compensate for poor insulation, too many windows, and the door being opened and closed constantly. Also, the bus had to be warmed up from dead cold, which is rarely an issue for an RV. I use MSR brand heaters, which have a pair of muffin fans like you'd find in a computer. Very low current requirements. I have five of the fan heaters, so ten muffins, and that keeps the whole coach toasty. There are several other brands on the market with more or less the same design; I think Aquahot (formerly Vehicle Systems) markets their own brand, for instance. -Sean http://OurOdyssey.BlogSpot.com | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1480 Registered: 12-2000 Posted From: 76.66.19.129 Rating: N/A |
Hello Grant. The coach blowers, as noted, are large capacity and a large draw of power, as well as making some noise. For bus conversion purposes, you want to have something quieter and less power hungry for maintaining the heat while camping. Whether you need/want the big capacity coach heat system is up to you and what you are going to do with the coach. This is an excellent time of the year to be thinking about this, as you may run some trials with your ideas for smaller capacity heating methods right now! My current set-up was done by the previous owner, who used the coach for a mobile classroom application with a small budget and no room to screw it up. The stock coach heating system and its controls were simply powered up without the engine and a big Webasto put inline to the coolant pipes to replace the engine heat. Costs of operation in fuel consumption, noise, and sleeping in it, were not considerations that mattered. I will do something else to stay warm, when I get around to it... The computer style fans are lovely quiet things...a nice heat exchanger could be constructed... and I have a number of lengths of finned baseboard radiator...or a used Airtop...or an electric heater....or lots of blankets...or I could idle the big engine.... happy coaching! buswarrior | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 653 Registered: 10-2006 Posted From: 64.241.37.140 Rating: N/A |
We regularly travel below freezing and have no hassles. The huge coach setup and dual 80A blowers was tossed. We use the dash air AND a boat style "box heater" 40,000btu cut into the origional penlum side supply. Works fine AND can be operated in warm weather as out side air pressurized supply. We can also operate the circ pump and blower in milder weather , to warm the cabin after shutdown , as long as the 8v71 block is warm. The huge setup for heat (at least in GM) was to warm air from the air cond system. Air cond could not be turned on while on the road , so the heater was needed, and did a fine job of dehumidifying the coach. But hardly needed for an RV . FF | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 104 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
You guys are a wealth of information, thanks. Well I have decide to run a webasto for the coolant system, with a bypass line and a couple of valves to direct the coolant in the direction that is needed at the time. Should work good. However now I have to decide what type of heat exchangers I will aquire. I sure like the idea of the small fans , computer style. I'm surprised that those do the job. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 440 Registered: 7-2006 Posted From: 70.210.130.104 Rating: N/A |
We kept the heat exchangers that came with our coach....under the counter, under the bed and two in front under the dash. They are all Bergstrom rated at 40m BTU each. Lots'a heat, small and 2@ three speed fans per unit. Might check your local school bus junk yard. Also, ... Vehicle Systems in Colorado had some on sale a while back....seems like they were about $70 each. Also.... try Ronthebusnut.com . FWIW RCB | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 105 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
Great thanks. I was thinking maybe a A/C condensor out of a small car. I have a friend in the auto body business and could get them for free then mount a fan behind. Install a 1/4 turn valve on the input side to control the flow. I think these units might be too big and where to mount such a thing that wouldn't look ungly. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1303 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
You can buy these from RED DOT company along with others, with fan and evaporator already in one unit and sell all the required items, etc. to go with it. Of course, if you're on a tight budget, car parts would work, although in the long run they both could cost about the same in labor/ cost. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 441 Registered: 7-2006 Posted From: 75.208.249.15 Rating: N/A |
Grant....the fans in our coach, and the way originally set up, are pullers (in front of the exchanger, pulling the air)...not pushers.... Don't know if therre is any difference, but that is the way Bergstrom set them up....in "cages". FWIW RCB | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 106 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
Not sure if there's a differance either, other than I think I could build it to be a little more attarctive if they were pushers. I did go look at some exchangers that John was talking about. They look like they would work quite well with the squirrel cage already built in. A little concerned about the draw on the batteries but It would work quite well I'm sure . Will probably just go with them. There's enough to build on a conversion without trying to build a proper heat exchanger. Thanks guys | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 449 Registered: 7-2006 Posted From: 70.212.223.228 Rating: N/A |
Well, Grant...all one need do is "turn" the unit around and wallah...it becomes a pusher  ...albeit plumbing then might be a concern... Then there is always wiring the little motors to run in reverse. (Graingers has them, as I recall) Lotsa' ways of skinnin' cats, so I'm told. Maybe I'm, "too simple". FWIW | ||
| Clint Hunter (Truthhunter)
Registered Member Username: Truthhunter Post Number: 35 Registered: 1-2009 Posted From: 24.129.235.190 Rating: N/A |
I too have considered those Airtops as auxiliary/alternative heating mainly due to the low power requirements and efficiency. Have not tested one as of yet I can not make claims for quality or actual performance. Taping into the factory fuel lines could be a feasible option with not to much room for complications provide it was not used while the engine was running. My idea was just to valve it at the primary fuel filter, isolating the engine supply with a 3 way valve. Use the air top , or use the engine, but not both at the same time. You would likely have to use a fuel booster pump, which means more power drain on the batteries and more costs. Likely still less power consuption than a larger single hydro distribution system. One of the notions beyond the low power potential was the comfort potential in having several of these units place through the bus for quite and efficient air distribution, and the option of zoning to reduce consumption ( think-keep the bedroom warm at night, and not as warm in the other areas). Like every design there are some trade offs, including the initial costs for the redundancy. I would not trash the coach heat, modify it perhaps in time. |