| Author | Message | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 111 Registered: 10-2007 Posted From: 206.45.93.160  Rating: N/A |
Well guys, I braved the not quite so cold weather on the week-end and roughed in 2 airtop heaters. Don't get too excited as I am still going to install a webasto into the coolant lines. However the curiousity was killing me about these airtops. I installed one in the bathroom (about 14ft from the back) and the other at the rear of the living area about 18 ft from the back or close to the centre of the bus. The back one is mounted in my water bay at the back and the other in the centre bay. I also believe it would be a good emergency heating system for the water bay if needed. I also installed a 75 gallon fuel tank in the centre bay so I can run these while the bus is operating if I need to. It was about -15 C or 5 F when I started the units up. The temp was dropping quite quickly outside as it was about 4:30 pm when I fired them up. I let them run for about and hour and a half. The bus had warmed up considerably. The gingerale that I had left on the dash of the bus was starting to melt although it still felt cool in the bus. Heating it up from a dead cold is quite a chore, considering it dipped down to -28C or -18F the night before and it was still colder in teh bus than it was outside. The idea of having the one in the bathroom is that I should be able to use it to heat the bath/bedroom(bathroom door to the living area closed) or the bath only, or help with the the bath/ living area heat(bedroom door closed). I had the doors open while I was running them last night so the whole bus was being heated. I do believe that these heaters will work well until we hit the deep freeze temps at which point I don't believe they'd keep up. Maybe with a 3rd unit, but I believe a webasto for the coolant lines will be in order for those temps. I am happy at this point that I did this as they do give off a decent amout of heat and will provide instant heat for those cool mornings etc. with little power. Have fun | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1346 Registered: 10-2003 Posted From: 71.58.110.9  Rating: N/A |
maybe these would be the ones to get if the price ever comes out of the stratosphere. http://cgi.ebay.com/ebaymotors/Webasto-DIY-Marine-Air-Heater-Air-Top-5000_W0QQcmdZViewItem QQitemZ220304524664QQptZBoatQ5fPartsQ5fAccessoriesQ5fGear | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 112 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
I think your right, I have the same units but one is a 2000 unit and the other is a 2200 unit. They do work well. I was actually surprised that it heated the bus up at all in that time frame. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1351 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
with the 5000 units, 18000 btu per each should do the job except extreme conditions. | ||
| Wec4104 (Wec4104)
Registered Member Username: Wec4104 Post Number: 14 Registered: 7-2008 Posted From: 68.80.242.72 Rating: N/A |
What I find really interesting about these is their efficiency. The Airtop 2000 (@7000BTU/hr) burns 0.06 gal/hr. Even if the thing runs non-stop without cycling, that's 12+ straight hours on $3 worth of diesel. The Airtop 5000 pumps out 17,000 BTU, but still only consumes 0.17 gal/hour. The only thing holding me back from replacing my propane furnace with two of these is the up-front investment. | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 640 Registered: 8-2006 Posted From: 74.32.92.133 Rating: N/A |
I know on live a board boat they tell you not to use a air heater for heat.Don't know how they hold up in a bus but they don't do that great in trucks from what I was told by a friend of mine that had them in his trucks and he told me they used over a gal every 10hrs and drew 8 to 10 amps (Message edited by luvrbus on February 18, 2009) | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 113 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
Interesting Luvrbus, I was told the oppisite from some local truckers, ha ha. I guess we'll see. At least I didn't break the bank on them. One local trucker had bought a replacement bunk to fix his up after an accident, and the replacement bunk had one so he sold it to me for 200 bucks and the other one came out of a smashed highway truck which I got for 400. the exhaust pipe wasn't even dirty on that one. | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 642 Registered: 8-2006 Posted From: 74.32.92.133 Rating: N/A |
You never know about truckers Grant he never liked the units he uses the APU now on all of his trucks,air, heating and power.But I do know about the units on boats the people that sell them told me not to use air heaters on mine Good luck (Message edited by luvrbus on February 19, 2009) | ||
| Wec4104 (Wec4104)
Registered Member Username: Wec4104 Post Number: 15 Registered: 7-2008 Posted From: 68.80.242.72 Rating: N/A |
If your trucker friend needs to run the APU for other reasons, then it makes sense he also uses it for his heating needs. If all he needs is heat, I have a hard time believing that running the APU is is going to be more efficient. I'm wondering if the advise not to use them on boats has to do with the "draftiness" of the area being heated. If you are pumping heated air into a space where there is a constant inflow/outflow, it is a loosing battle. The heated air won't spend enough time there to heat the surroundings. Putting this in real world terms, the leather sofa you go to sit on will always feel ice cold. With certain infrared or radiant type systems you might have a fighting chance. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1352 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Maybe the salt in the air causes corrosion buildup in the heating chamber. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 699 Registered: 10-2006 Posted From: 66.82.9.61 Rating: N/A |
The Airtop 2000 (@7000BTU/hr) burns 0.06 gal/hr. Even if the thing runs non-stop without cycling, that's 12+ straight hours on $3 worth of diesel. The Airtop 5000 pumps out 17,000 BTU, but still only consumes 0.17 gal/hour. Some strange math here,,,, a Gallon of diesel is perhaps 160,000BTU divide that by "burns 0.06 gal/hr." to find the burn rate , then figure 0nly 50 or 60% efficency. FF | ||
| Wec4104 (Wec4104)
Registered Member Username: Wec4104 Post Number: 16 Registered: 7-2008 Posted From: 68.80.242.72 Rating: N/A |
For the Airtop 2000: If a gallon of diesel has 160,000 BTUs, then 0.06 gallons has 9,600 BTUs. The stated output of this unit is 7000 BTUs. So, 7000(actual)/9600(theoretical) = 72.9% efficiency For the Airtop 5000: 0.17 gallons has 27,200 theoretical BTUs 17,000 (actual) / 27,200 (theoretical) = 62.5% efficiency These numbers seem feasible to me. Fred, are you saying the devices should be more efficient, or that the manufacturer claims seem overstated? | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 643 Registered: 8-2006 Posted From: 74.32.92.133 Rating: N/A |
A gal of diesel is 139,000 btu fwiw | ||
| Wec4104 (Wec4104)
Registered Member Username: Wec4104 Post Number: 17 Registered: 7-2008 Posted From: 68.80.242.72 Rating: N/A |
At 139,000 BTUs, the numbers work out to: Airtop 2000 = 83.9% efficiency Airtop 5000 = 71.9% efficiency These are even better, and still within believable ranges. | ||
| Wec4104 (Wec4104)
Registered Member Username: Wec4104 Post Number: 18 Registered: 7-2008 Posted From: 68.80.242.72 Rating: N/A |
A side question or two for Grant... You mentioned that you installed a separate 75 gallon tank so you can run the heater while the bus is operating. Why is it that you cannot run them off the main tank? Only one output from the main tank and some limitation on the pickup? Is the 75 gallon tank dedicated to heater use? If so, will you be filling it with dyed diesel? | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 114 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
I have only roughed in the tank so far. I have built the straps etc but have not installed them yet. I have heard that tapping into the main tank can cause issues with either the heaters or the operation of the bus. Therefore I thought I would install a seperate tank as I had been given a decent tank for free. It fits well so what the hec. I will also be running a coolant type webasto off of this tank and as you mentioned it does open up the option of running dyed diesel. I maybe didn't have to do this but thought I would play it on the safe side. I believe that teh fuel pumps for all 3 heating units won't have to work quiet as hard either as the fuel is sitting right at the pump due to gravity. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 503 Registered: 7-2006 Posted From: 75.209.52.103 Rating: N/A |
Grant....if one taps in "at the tank", picking up as with your normal fuel line, there should be no problem. It is when the tap is IN the fuel line, scarfing off fuel to the engine as it were, that there are problems. As I recall, that is spelled out in the Webasto literature. Sure Marine has all kinds of help for anyone who seeks it...as does Vehicle Systems. FWIW  RCB | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 115 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
Makes sense, thanks. It would save alot of room in the bay. I am first of all going to install eveything with this tank as the feed, then (given the info you guys have given) I'll run my fuel line from the bus tank. Each one of these heater units have their own individual fuel pump. Therefore should I run a larger fuel line such as 1/2 inch back from the tank then have these pumps feed off of it? Do I need a seperate fuel pump by the fuel tank to easy the load on these other pumps? My concern is that these little pumps will have to pump the fuel quite a distance. It would probably work but wouldn't that lessen their life span considerably? | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 504 Registered: 7-2006 Posted From: 75.208.238.82 Rating: N/A |
Grant....FWIW.... ...since the Webasto heaters use so little fuel,(compared to the engine) somehow the use of a second tank, particularly of that size, seems to me over(the top) redundant and a waste of very, otherwise, usable bay space. Don't misunderstand, please; I'm not criticizing you. Just looking at it from my usual "practical" approach to things....especially the coach. I have "utilized" (almost ashamed to say that, but it is the truth) this forum for 8 years +- and value other's experience and input.....one of the reasons I have always respected Fast Fred's comments; among, of course many,many others. But, alas, as he always says...."do it your way".. RCB | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1261 Registered: 5-2001 Posted From: 65.74.69.188 Rating: N/A |
Grant, our coach gets 10 MPG on about 1/3 of our runs. Since we drive around 62-65 MPH, that means that we are burning nearly seven gallons per hour. Driving flat out, we could burn twice that. Since most of the fuel pumped is returned to the tank, that means that the system is sized to handle somewhere around a gallon a minute. Diesel fuel runs around 140,000 BTU, and seven gallons is around 1,000,000 BTU. These diesel engines run around 34% efficient which means that 1/3 of the fuel energy turns into mechanical power, another third turns into heat to go out the exhaust and the last third is heat kicked out of your radiator and heating system and off of your block. Your other uses for the fuel will not affect the engine much if everything is in good working order. If you get 7.5 MPG, then you are using around 1 1/3 million BTU per hour but the energy is still split three ways IF you are making power out of it. When an automatic is added to the mix and the economy falls to 7.5 MPG, this means that 1/4 of the mechanical energy is turned into additional heat in the transmission. This means that the power lost in the transmission must be replaced by burning more fuel, producing more waste heat. I didn't mean to hijack your thread; I was just trying to get you to look at the larger picture and to do some of the math so you could figure out the flows that are involved. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1353 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Two nice things about running an extra tank, which doesn't need to be that large. One: You can use furnace dyed fuel in that tank, which should be about approx 40 cents per gallon less, depending on where you reside. B: You could plumb a line to the regular fuel tank to get extra capacity or for low fuel emergencies. ( lets not get into using dyed fuel in coach engine; that's your risk) And 3: this way, you can more accurately compute the coaches fuel consumption. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 507 Registered: 7-2006 Posted From: 75.211.3.63 Rating: N/A |
Well, JWR.....while I agree with you fundamentally on all three points....me thinks that is stretching them all: In an RV (motorhome, whatever one wants to call it) one is not subject,in most instances that I am aware, to use CDL diesel....I don't know about all states, but I would not hesitate to use it wherever... If a coach is licensed as a MH, there is,most probably, no requirement to meet other standards. Why couldn't one just carry "xtra" fuel...as in containers, for such an emergency. I do. My Webasto draws from the coach fuel tank (separate line from the top of the tank)...110 gallons... if one has a fuel gauge and is familiar with the reading on same, one would know when to re-fuel....usually. Or, as we do for redundancy, carry a "stick" to put in the tank... (if one per chance would not "believe" the reading of the gauge). Just a Saturday Night, with nuttin' to do but...talk FWIW ...and Thanx for the engagement. RCB | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1496 Registered: 12-2000 Posted From: 76.71.100.173  Rating: N/A |
As usual, it depends on the relativity... Depending on the amount of fuel one will use to keep the coach warm, (and run the gen, if applicable) having a separate tank in order to take advantage of a fuel that is not taxed for road going (typically dyed diesel) may be of quite a significant savings. For a busnut who is not full timing, the cost/benfit for having the separate tank will be high, in little cost savings, and a large loss of space. But, that all depends on what you want. Build it your way, you are free to be happy, or free to be happy to change it after doing your own trials. The glory of this hobby is being happy doing your own thing, and darn the rest of them/us. happy coaching! buswarrior | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 275 Registered: 10-2003 Posted From: 74.244.14.221  Rating: N/A |
Very true BW. In my case I have an all electric coach with only the coach defroster retained so if I am not running my gen I have no AC, no heat, no refrigeration etc. Since my gen is running anytime I'm not plugged into a pole I do have a separate fuel tank to use dyed diesel which is a major savings. Actually the old FLx already had a separate tank which origionally powered a gasoline engine that drove the coach air. Really convenient because the gen is in the old coach air bay so all the hard lines were already in place. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1354 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Chuck....you don't think that it is unlawful to use dyed diesel in your coach engine in some areas? | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 514 Registered: 7-2006 Posted From: 75.211.194.39 Rating: N/A |
What I have said....I have said..... Some areas??? I don't know, but I do feel that a registered Motor coach, Motor Home, Recreational Vehicle, or whatever a state wishes to call it, is, most probably the definition that MOST other States, Provinces, etc, would accept. After all, one does carry a registration, title, or whatever...hopefully. Now then...go out looking for trouble....one would most probably find it. For us...we have not had a problem...thus far. To date we have not been stopped other than at the Canadian Border or Border Patrol facilities, and that only for routine inspection or questions. When I can pull in to a facility that offers both, (Pilot, for instance) I will "fill" from the retail island. If for no other reason, I can use a credit card and pay the "cash " price. Not so in many places at the truck fill. (Pilot, for instance). Usually a minimum 5 cent extra charge if one does not use the "correct" (proprietary) credit card....(or indeed any credit card) FWIW......Just My way... RCB | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 704 Registered: 10-2006 Posted From: 66.82.162.16 Rating: N/A |
Just discovered that the ease and speed of filling at the truck island at F***ing J also costs more. So now we plan fueling at lunch time and use the far far slower RV /auto pump , so we eat lunch as it fills. FF | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 116 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
I guess what I'm asking is, how do I mount another feed out of my bus fuel tank, ( drill and additional hole in the top of the tank for the feed?) and do I need another electric fuel pump to get the fuel to the rear bay where 2 or the 3 units will be located. Thanks for all the info and thanks for making me think Tom ! | ||
| William Garamella (Nh_wanderer)
Registered Member Username: Nh_wanderer Post Number: 9 Registered: 11-2008 Posted From: 24.62.162.30  Rating: N/A |
Heads up for those in the market. I noticed two nice looking Webasto 2020 24 volt units on e-bay. I am not connected in any way with these auctions. Just a satisfied Webasto user passing information on. http://tinyurl.com/bs2gr8 NH Bill | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 515 Registered: 7-2006 Posted From: 75.208.2.4 Rating: N/A |
I would ass.u.me that, as in my case, there is either another access port on the top of your tank...or that one could "adapt" the existing port to accommodate two draw lines. Very simple on ours...just put in a line straight down...to within about 3 inches of the bottom (to prevent the Webasto from consuming all fuel). Top connections should be readily available...NAPA, Fleet Pride, etc. There is no extra fuel pump required on my Webasto...it is built in. Would highly recommend an in line filter, however. IMHO....the shorter the run, the better. FWIW HTH RCB | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1499 Registered: 12-2000 Posted From: 76.66.17.236 Rating: N/A |
From my mobile command vehicle days... Including a priming bulb in the line (outboard motor boat style) has solved all manner of trouble without using tools or getting covered in fuel. You may never squeeze it again after install....but it sure helps if you ever have to do some maintenance that involves taking the fuel lines off, or develop a leak that allows draining back to the tank. Inexpensive insurance/convenience. happy coaching! buswarrior | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 117 Registered: 10-2007 Posted From: 206.45.93.160 Rating: N/A |
Thanks guys, that is what I ws looking for. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 517 Registered: 7-2006 Posted From: 75.209.73.211 Rating: N/A |
Grant...perhaps I missed something along the line; do you not have an operator/installation/repair/parts manual? This is a fine piece of equipment and you deserve to get the most/best out of it. If not, I would encourage you to contact Vehicle Systems. Sure Marine or one of the distributors...I have found them very willing to furnish information and help...also the Webasto Web site has (had) lots of information, including manuals, as I recall. 'Twill make your experience much more understanding and...pleasureable, me thinks. FWIW, RCB |