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Date:         Wed, 6 Oct 1999 02:46:18 -0500
Reply-To:     Marshall Ruskin <mruskin@PANGEA.CA>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Marshall Ruskin <mruskin@PANGEA.CA>
Subject:      BA6 Heater Information - long
Comments: To: Marshall Ruskin <mruskin@vulcan.achq.dnd.ca>
Content-Type: text/plain; charset="iso-8859-1"

This post is taken from the Vanagon Archives, and seems to be an excellent treatment of the BA6 heater. Thanks to Mark Shelfo for the reference.

Marshall Ruskin

>From: Jack Reed <jackr@fortnet.org> >Subject: Eberspacher BA6 heater article (long) > >Here you go folks, >Please send me any comments, questions, etc., that you have and I'll do >my best to answer them. >Jack > > >INTRODUCTION > > >This is being written for all those that want some heat in their >air-cooled vans. It's also written for those that just want some info >on gasoline heaters before taking the plunge, either by doing it >yourself or by having someone else install it for you. > >------------------------- OBLIGATORY DISCLAIMER ----------------------- >Before we proceed I'd like to offer a few words of advice concerning >gasoline heaters. THEY ARE VERY DANGEROUS AND CAN BURN YOUR VAN WITH >YOU IN IT TO THE GROUND IN A MATTER OF MINUTES. IF YOU DON'T KNOW WHAT >YOU'RE DOING, SEEK OUT A MECHANIC OR DEALER THAT DOES. Sorry I had to >shout, I just wanted to make sure that everyone was paying attention. > >All kidding aside, these things can be very dangerous if they are >misadjusted or if the safety interlocks are broken or defeated. I have >heard of older units that had no safety interlocks built into them >whatsoever. I would be very cautious about having one of these units >installed in my vehicle for the simple reason that you, the driver, are >then responsible for ensuring that everything is always in proper working >order. If someone else installs such a unit for you, you may not be >capable of determining when a problem with your heater occurs, with >possibly disastrous side effects. > >One other note before we proceed. I installed an Eberspacher BA6 heater >in my 1981 Westphalia from scratch, which means that there was no heater >in the van when I started. The rest of this article refers to >the BA6 since it's the only heater I have any direct experience >with. You should be able to draw certain references about general heater >operation from this article but be careful about making assumptions >about your unit if you determine that it's decidedly different in >operation from the BA6. > >All comments and observations in this article are from personal >experience and recollections. Refer to the appropriate manual for your >heater for exact specifications, trouble shooting tips and maintenance >guides. This article is meant to be a general info guide only for the >DIY heater mechanic/installer and for those interested in learning more >about their operation. > >Before I talk about the installation phase, let's talk first about >general heater operation. A gasoline heater is really a very simple >affair. Basically they are nothing more than a carbureator, since they >employ a simple metering system for fuel delivery, a spark or glow plug >for ignition, a means of delivering intake air and exhaust of spent >gases. Surround the whole thing with safety interlocks and you've got >a gasoline or deisel heater. > >Each manufacturer (Eberspacher, Stewart-Warner, Southwind to name a few) >has a slightly different way of accomplishing these tasks. This article >is going to concern itself only with the Eberspacher (or Espar as it's >known in Canada and the US) BA6 which was originally installed in early >air-cooled Vanagons. > >COMPONENT DESCRIPTIONS >The BA6 has several different "packages" associated with it. By >packages I mean blocks of components that are installed in certain >specific parts of the van. The most important part of the installation >is, of course, the heater itself. This is a long, flat pancake made of >sheet metal that basically consists of two parts, the inner shell and >the outer shell. Think of it as two clams, one inside the other if >you're having trouble visualizing it. At one end is where the >combustion motor fan, the spark/glow plug, the inlet for the fuel from >the fuel pump and the temperature regulating sensor reside. In the >middle are the flame and overheat switch and at the other end is the >exhaust pipe. > >The combustion motor fan does two things, supply air to the combustion >chamber by means of a rotating, finned fan as well as supply the signal >to the fuel pump and the ignition coil by means of a set of points that >are tripped by a cam on the end of the motor shaft. The Bentley manual >gives directions for adjusting the fuel pump by the number of "ticks" of >the points, but as we'll talk about later, this method is only good for >sea level installations. The fan pulls outside air through a 2' >corrugated plastic pipe that plugs into or connects to a hole in the >rear cross member. Great care must be taken that this plastic pipe is >secured at both ends, otherwise vacuum could be created at the >combustion motor fan inlet by air rushing by. This would cause the >flame that normally is contained in the heater to be pulled outside of >it, which could cause meltdown of your heater, your van and you. > >As just something else to go wrong (not really), the combustion motor >fan has a little "propeller" on the end of the fan itself that creates a >long flame path in the heater to ensure complete combustion. If this >propeller is not in place because it was burnt off by an incorrectly >adjusted mixture, you'll have to find/buy another. Otherwise it's >impossible to get your heater adjusted properly and you'll find it's >operation intermittent at best, inadequate at worst. I've been told >that these fans are "mated" to the motor and that replacing just the fan >will cause premature wear of the bearings, resulting in a $200+ >replacement. This is reason enough to ensure that your heater is >properly adjusted at all times. > >The spark/glow plug is just that, a spark plug that sits in the stream >of gas from the fuel pump. It has it's own ignitor or ignition coil >that also gets it's signal from the points in the combustion motor fan. >The spark/glow plug consists of an inner electrode, exactly like a spark >plug and an outer shield that looks like a small, drilled tube. Even >though I've never seen one in action, I assume that once the spark gets >everything nice and red hot, the shield just serves as a secondary >ignition source for the fuel. > >At the base of the spark/glow plug inlet is a short metal tube that >receives the outflow from the fuel pump. By having these two points >essentially coincide, the designers ensured that all fuel would be burnt >as completely as possible. Even so, these units were not designed with >emissions in mind, although I have heard of mechanics that used their CO >machines to adjust the fuel pump, hingeing on the 14.7/1 ideal air/fuel >mixture. I haven't been able to convince my dealer to let me use his CO >machine for this purpose yet due to the excessive heat generated at the >exhaust pipe. > >Which brings us to the other end of the heater, the exhaust pipe. This >pipe is bent in a 90 degree angle so that the exhaust doesn't shoot >directly at the end of the transmission. About one inch past the end of >the pipe itself is a metal cap, roughly the diameter of the pipe, which >is held in place by two metal straps that connect to the end of the >exhaust pipe. This pipe is there to ensure that the exhaust does not >ignite leaves, etc. that rest underneath the van. There have been >documented reports of this occuring so make sure that your exhaust pipe >is in place and has the cap as well. If the cap is missing or damaged >by some fumble fingered parts yard mechanic like mine was, you can >easily fashion another using pop rivets, iron strap, and a small circle >of 1/16" to 1/8" iron. Don't use sheet metal for the cap, the heater >will burn right through it. An additional benefit of the cap that I've >only surmised and never really researched is it's action as a venturi. >The flow of air between the cap and the end of the pipe creates a >natural vacuum that creates an increased draw of exhaust through the >heater. I'm not sure if this is true or not, but it's likely, so make >sure that your cap is in place. > >In the middle of the heater is a contraption called a flame switch. The >purpose of the flame switch is to provide a signal to the control unit >that the heater is up to temperature. This signal is provided by a >micro switch that is tripped by an expanding metal shaft that resides in >the heater's core. The flame switch is tricky to get adjusted properly, >as the micro switch is held in positon by two screws terminated by nuts. >The only way I'v ever been able to get mine adjusted correctly is by >using a propane torch and a DVM. Once I've got the micro switch in what >I think is the correct location, I lock down the screws as tight as I >can get them. Then I set the DVM on the OHMS position and place the >metal rod in the flame from the torch after hooking the DVM to the >common spade clip and the NO spade clip. If the meter shows infinity >when the rod is cool and ~0 when in the flame for a few seconds then >you've got it right. The rod can get red hot pretty quickly while in >the flame from the torch so be careful where you place it when you're >done checking the adjustment. > >The flame switch adjustment has been at the heart of 90% of the >problems I've had with my heater, so make sure you get it right. If >you're unclear on what's happening there or how to follow my directions, >write me at the address at the end of the article and I'll give you a >hand with the procedure. The other 10% of the problems have been due to >an incorrect mixture, which resulted in the premature demise of my first >combustion motor fan. This resulted in incomplete combustion of the >fuel and erratic operation of the heater. Information is provided on >adjusting the fuel/air mix for your unit later on in the article. > >There is also a metal "button" in a ceramic ring that fits beneath a >clip on the top of the heater. This is called the overheat switch and >it's nothing more than a breaker that will kill power to the heater if >the temperature of the heater's outer "skin" gets too hot. This could >happen if the fuel pump were to lock in an open state, allowing >unrestricted fuel to create a "runaway" situation. It's your final >defense against meltdown so make sure that it's in good condition by >running the checks recommended in the manual. > >The two halves of the heater are held together by the use of rivets. If >any of yours are missing, pop rivets can be used to resecure the unit. >The heater itself works like any home furnace you're familiar with >where the actual combustion occurs in the inner jacket (or clam, if >you're still using that image as a guide) which then heats the air in >the cavity made by the second jacket (or clam). The exhaust pipe runs >through this outer cavity to get to the outside of the heater. > >Warm air is pushed through this outer cavity by means of two fans, the >squirrel cage on the end of the alternator and the auxiliary fan that >draws air through a hole cut in sheet metal underneath the rear seat. >The auxiliary fan pulls the air from the heater boxes that surround the >exhaust manifold and the squirrel cage fan pushes air through them. >Another plus (besides the added boost of warm air) provided by the >auxiliary fan is that by drawing air from underneath the rear seat it's >recirculating warm air that's already in the passenger compartment. >This means that the heater doesn't have to continually supply heat, it >only has to replace the heat lost to air leaks and convection losses >through the body, roof and floor. I live in Colorado and these losses >amount to a lot when it's 20 below outside and you're scooting down the >road at 65. > >The fuel pump is a small, 4" affair that connects to the fuel line after >the fuel filter. Make sure that you get the "tee" for the main fuel >line and the clamps that hold it in place, you'll need them to splice >into the main line. I've heard the fuel pump described as nothing more >than a hypodermic in it's operation because of the way that it squirts >gas down the hose the heater. It attaches to the cross member by means >of a rubber bushing and a nut and bolt. > >At the front of the heater is a temperature sensor. It's a criss-cross >arrangement with a resistor in the center of it. It's used in >conjunction with the thermostat to regulate the heater's output >temperature. The sensor sits in the output stream to the passenger >compartment at the front of the heater. > >The final part to the heater section is the belly pan, a long, wide >section of pressed sheet metal that runs from the gas tank to the >transmission and between the frame rails. The belly pan serves two >functions, it protects the heater and it's components from rocks, salt >corrosion, etc. and it traps "some" of the heat produced by the heater. >There's a small door in the center of the belly pan to give you access >to the flame switch. There's also a cutout in the sheet metal to allow >you to adjust the fuel pump without having to remove the belly pan. >I've often thought about insulating the belly pan to reduce heat losses, >but haven't only because I can't figure out why VW didn't insulate it in >the first place. I suspect there's a good reason for this and until I >find out what it is I'll live with the heater in it's present state. If >someone has an insulated belly pan in use for several years I'd >appreciate hearing about it. > >Last (didn't I say "final" in the last paragraph?) but not least are the >two short sections of duct that connect the heater to ductwork at the >front and rear of the engine. These pieces of duct are needed to splice >the heater into the old, single pipe that used to carry heat direct from >the heater boxes to your frozen tootsies. The ducts should be in good >shape, with no cracks or breaks in them. Suitable replacements could >probably be gotten from a heating/ventilating shop if the dealer's >prices are too dear. > >If after you've got the heater installed and running, it sounds like a >locomotive has taken up residence there in the van with you, the inner >jacket is cracked. You need to get another one since I'm not sure if >such a crack can be repaired. I'm not saying it's impossible, just that >I've never had to have it done so I can't say whether it's possible or >not. In any event, the heater is unusable until you get it replaced or >repaired since carbon monoxide will be venting directly into the heated >air flow to the passenger compartment. Just in case no one's told you >by now, carbon monoxide will kill you, either by depriving you of oxygen >or by causing you to fall asleep at the wheel. > >The person that told me about this sound being produced by a crack said >there's no mistaking it from the normal sound of the heater in >operation. If you're not sure if yours is cracked or not, but suspect >it may be then have a heater/ventilator guy or gal probe the output from >the heater in the passenger compartment with a CO sniffer for excessive >fumes. I can't caution you enough about this. It's better to freeze >then to die from carbon monoxide poisoning and possibly kill other >innocents in the process. In fact, after all is said and done, it's >probably not a bad idea to have someone probe the heated air for CO as a >final check of your work. > >That covers the components directly associated with the heater >itself. Let's move to the back of the van now, in the cavity between >the bottom back of the rear seat and the engine. A hole needs to be cut >in this sheet metal to allow the auxiliary fan a place to pull air from. >Make sure when you get your heater that you get the plastic cover and >foam gasket that the fan mates to. You can use the cover as a template >when it comes time to cut a hole in the sheet metal. There are two >"dimples" in the sheet metal that you can drill out to receive the >screws the hold the cover in place. Once you've got the hole cut find >a logical place to hang the auxiliary fan from so that it will mate to >the port that juts out from the cover. > >Next you need to replace the ductwork that routes hot air from the >control flaps to the original duct to the front of the cab. These >two units are almost identical, the only difference being a port to hook >the auxiliary fan onto. This is pretty straight forward, just check >that the one-way air flaps in the ductwork are in place and functional, >otherwise part of the pressure from the fan will just wind up fighting >against the pressure from the squirrel cage fan and you'll wind up with >zip for heat. While you're back there it's a good idea to R&R the >control flaps so as to get maximum heat out of the heater boxes. > >The last package of components are those that fit under the dash. >Although these components can be installed without pulling the dash, it >makes for a much cleaner, easier time of it if you do pull it prior to >installing them. There are five main parts to this phase, and we'll hit >them one at a time. > >First there is the extension to the fuseblock that holds the two >additional fuses for the heater's operation. Didn't get it when you >pulled the heater? You can use the appropriate sizes in in-line holders >instead. > >Next is the timer/thermostat, it goes in a hole in the dash just below >the instrument cluster and to the right of the steering column. If >there isn't a dummy hole already in place try and pick a spot where >you'll have room behind the hole to mount the thermostat. The timer >section of the thermostat allows you to preheat the heater on a cold >Winter's morning. Don't run the heater off the timer more than once >when it's real cold or you take the chance of running the battery too >low to start the engine. Press in on the knob with the "+" on it and >turn it to the right, you should hear the watch mechanism ticking >merrily away. If not then something's jammed the works and you'll need >to take it apart to get it working again. It's not absolutely critical >that this section of the part works, so don't sweat it too much if it's >broken. Normal means of heater actuation is to turn the knob to the >right without pressing it in first. > >Then there's the safety switch, which mounts there by your right knee >when you're sitting in the driver's seat. It has a bimetal relay that >will "blow" if the heater doesn't come up to temperature fast enough or >if it doesn't keep putting out heat after the flame switch rolls over to >it's "closed" position. > >After that there is the heater relay which makes an audible "snap" when >the heater kicks on or cycles. That goes over in the area behind the >glove box. Last but not least, you need to replace the heater levers >there in the dash. The replacement lever assembly has a contact on the >right or "HOT" side of the lever that supplies a ground signal to the >electronics package. I suppose that someone could bypass this step and >just install a toggle switch in it's place but care would have to be >taken to ensure that the temperature control lever was in the "HOT" >region before the heater was actuated. Otherwise heat from the heater >boxes would be cut off. > >I'm not going to go into all the checks associated with these >components by duplicating the work the Bentley technical writers put >into the manual. Suffice to say that you should pick one up and run the >checks that they recommend. If you can't afford the manual (and at $90+ >a pop who can?) there are several outfits that will sell you a copy of >the heater section of the manual for around $10. Or find someone who >has a copy that is willing to make you one. I don't have one. Nope, >not me, uh uh, don't ask. Well, I don't know, maybe if you ask real >nice. > >INSTALLATION > >Installation is pretty straight forward if you take your time and start >sometime in June. If you wait until September when the first flakes >start flying you'll probably make a mistake and fry something that you >can't afford to replace. Try and start early if at all possible. > >I performed the installation in three phases: underdash components, >engine area components and under van components. Check your work as you >go and replace anything that looks borderline like rubber boots or fuel >lines. If you have the room and the tools, check each component for >proper operation by hooking them up to 12VDC or by performing whatever >resistance checks you can before installing them. I laid everything out >on my garage floor and made sure that I knew where all the wiring and >connectors went before I started the install. Then I visualized how >everything hooked up, where it was located in/on the van and how best to >route the wiring. Once that step was done, the rest just fell into place. > >Uh huh. Believe that and I've got a bridge to sell you. This is a >painstaking labor of love that will easily consume at least three >weekends over several months before it's right. But your >wife/kids/friends/frozen nose will thank you for the time spent doing it >right. I'm sure that someone could install a BA6 faster than that, but >that's how long it took me and I've spent 24 years crawling around all >sorts of vehicles. If your level of expertise is less than that you may >want to start in April (just kidding). I don't feel that this is too >much of a job for anyone with a fair degree of mechanical/electrical >understanding. But you will use all of that knowledge and then go >looking for more, so don't rush the job if you don't have to. > >When it comes time to mount a component to the body, such as the heater >or the safety switch, look for little "dimples" in the sheet metal. >This is where you need to drill a hole to accept the screw for that >component. Be careful of punching through whatever is behind the dimple >so that you don't, for example, punch a hole in the van's floor. The >bushings that the heater hang from will probably get trashed by whoever >pulls the heater, mine were. They run around $1.50 each from the dealer >and I'd suggest that you install them as they will isolate the heater >from road shocks and bumps. > >Items to check when inspecting a used heater are: >- no worn through rust patches, in fact no holes at all >- no big dents, the inner shell could be collapsed >- good bearings on the combustion fan, with little or no play to them >- points in combustion motor fan are in good shape (pull the end cap to > check them) >- apply 12V to combustion motor fan to check operation, keep your > fingers, hair clear of the fins when performing this step as it runs > at ~7000 rpm >- that combustion motor fan does not show signs of excessive heating and > that the little propeller on the end is intact >- correct resistance on the ignition coil (check Bentley for specs) >- spark/glow plug electrode and shield are in good shape and aren't > burnt or melted away by excessively high temperatures >- apply 12V to the fuel pump, if it doesn't "click" it's probably NG >- apply 12V to the aux. fan to check operation, check it's bearings also >- rubber hoses to/from the fuel pump, replace if cracked >- high tension wire to spark/glow plug, replace if not perfect >- plastic pipe to combustion fan has no cracks and seals well to cross > member receptacle and combustion motor fan inlet pipe >- that flame switch rod is straight, micro switch adjustment correct >- inspect ductwork for cracks, repair with hi-temp silicon, epoxy, etc. >- that all electronic components pass recommended electrical checks > >ADJUSTING THE FUEL/AIR MIXTURE > >Here's the part you've all been waiting for, adjusting the fuel/air mix >(which is why I put it at the end of the article, naturally). The >manual states that 18.4 to 21.7 cm. of fuel should be dispensed every >200 ticks of the fuel pump. I did this and the heater smoked liked a >runaway freight train. Due to the nature of the beast, that being that >these heaters are nothing more than big carbureators, they have to be >setup for altitude. Since there's no timing adjustment you can only >throttle back on the fuel to accomodate the lower oxygen density at >higher altitudes. If you're in the mountains (I'm at 5,280') then you >want to keep throttling back on the fuel pump until the heater stops >smoking. Leave the heater at this setting for a week or so then check >the tabs and propeller on the end of the combustion motor fan. If the >tabs, etc. show signs of being burnt you need to richen the mixture a >little so as to cool off the charge. If you get things too lean you'll >fry the fan and the heater won't work very well if at all, so keep >checking the state of the fan until you're happy that it's not getting >toasted. > >The only other way to adjust the heater properly is by use of a CO >meter. I'd suggest using a length of muffler pipe on the end of the >exhaust pipe so as to cool off the effluent as much as possible. >Otherwise you take a chance of frying the probe on the dealer's $15,000 >emissions machine. And he won't be very happy about that. If you can >get someone to let you use their machine, set the heater at 1.5% CO, >which is the ideal stochiometric ratio of fuel to air. I'd still check >the fan a couple of weeks afterwards just to be on the safe side. But >I've already roasted one fan so I'm a little more cautious than most. >Those things are hard to find and you'll pay dearly for one when you do. > > >That's it. Pick a nice shady spot to do the installation and take your >time learning how the whole thing works and goes together and you >shouldn't have any problems. I can be reached by email at >jackr@fortnet.org if you have any questions about the installation, etc. >Good luck and enjoy your old rolling icebox turned four season Van! > > > >


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