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  View original topic: Heating FAQs - BN4 Gas heaters & heating related topics Page: Previous  1, 2, 3, 4, 5  Next
KPK Wed May 12, 2010 4:26 pm

I just bought a 73 Thing and am starting to look at the heater. I noticed in the pictures that there is a small heat shield (or something) that is over the exhaust. Mine doesn't have one - is that a necessity and if so soes anyone know where to get one and how much they cost?

Captain Spalding Wed May 12, 2010 5:53 pm

$45 at the Thing Shop.


crofty Thu May 13, 2010 7:47 am

http://www.thesamba.com/vw/classifieds/detail.php?id=947594

much better price

KPK Thu Jun 17, 2010 12:06 pm

Do you have to pull the gas tank to get to the heater fuel pump?

crofty Thu Jun 17, 2010 12:36 pm

KPK wrote: Do you have to pull the gas tank to get to the heater fuel pump?

No but it makes things much easier.

Be a good time to change the fuel lines too.

man130 Thu Jun 17, 2010 12:46 pm

Its fairly easy to get to with the wheel turned, you can see it and reach in. if still have a problem just pull rim off. I see no need to pull tank

KPK Fri Jun 25, 2010 7:35 am

Thanks Guys. Appreciate the info and advice.

Worknclassbug Fri Nov 26, 2010 9:08 am

I have a simple question that I haven't been able to find an answer to. There is a ton of heater info on here and it's hard to filter through. Do you have to remove the heater unit from the car to work on it? I need to check the points/cam that controls the fuel pump because when I put a test light on the fuel pump leads I get a constant light on and no pulses like it should according to the manual. I think the nylon gear that has the cam on it may be shot. What is the easiest way to remove the fan assy? Thanks.

///Mink Sat Nov 27, 2010 12:42 pm

Worknclassbug wrote: What is the easiest way to remove the fan assy? Thanks.

I just posted some pics that might help you at the end of this thread:

http://www.thesamba.com/vw/forum/viewtopic.php?t=352241

Fun 181 Fri Jan 07, 2011 8:31 am

FYI-
Updated wiring diagrams for the BN-4 heater have been created by Captain Spalding, and can now be found in the Technical Section of the Samba forums.

Captain Spalding wrote: Update Notice:
Date: 1/6/11
New drawing added - Eberspächer BN-4 Ladder Diagram
Describes components of the BN-4 heater and their relationships to one another.

Technical>Wiring>Thing - bottom of the page in the "Other Wiring Diagrams" section.

Special thanks owed this time to "Speedy" Jim Mais, who created the source document, and to Emeritusx, who helped me wrap my head around it.

Also, here is a related post titled "BN-4 Heater Timer" and addresses a few electrical issues regarding the heater which may be helpful...
http://www.thesamba.com/vw/forum/viewtopic.php?t=445667

oasis Sat Jan 29, 2011 2:21 am

Can a gas heater be made to work with a fuel cell that replaced a gas tank?

Captain Spalding Sat Jan 29, 2011 11:57 am

oasis wrote: Can a gas heater be made to work with a fuel cell that replaced a gas tank?
I don't see why not as long as all the controls are there. The fuel cell must be positioned in such a way that fuel is fed the the heater fuel pump via gravity. If you are thinking of setting up a heater to run elsewhere than in the vehicle, you should take particular car regarding the combustion intake and exhaust, so that you are not burning the air you are breathing nor polluting it with the heater exhaust.

Worknclassbug Sat Jan 29, 2011 7:02 pm

We finally had a day above freezing here and I took advantage of it to work in the garage. I got a new (used) exhaust pipe and some other parts for my heater and installed them and fired up the heater for the first time. After I let it run for a few minutes with the fuel line off to get gas pumped up to the end of the line I connected the fuel line and the heater fired right up and ran great for about a minute and then I could hear the flame kind of intermittently going out for a second or two. Then after a couple of minutes the safety relay tripped and the heater stopped. I reset the relay and the heater restarted and was still having intermittent flame outs every few seconds and the safety relay tripped again. Is this possibly because of air in the line and is the safety relay tripping because the chamber isn't getting up to temperature? I'll try to let it run tomorrow with a clear fuel line on it so I can watch for bubbles.

oasis Mon Jan 31, 2011 11:49 am

Captain Spalding wrote: oasis wrote: Can a gas heater be made to work with a fuel cell that replaced a gas tank?
I don't see why not as long as all the controls are there. The fuel cell must be positioned in such a way that fuel is fed the the heater fuel pump via gravity.
Thanks. I imagine if/when I get to that stage, I will consult the fuel cell manufacturer.

Captain Spalding wrote: If you are thinking of setting up a heater to run elsewhere than in the vehicle, you should take particular car regarding the combustion intake and exhaust, so that you are not burning the air you are breathing nor polluting it with the heater exhaust.
I'm not sure if I understand you here. Do you mean running the heat from from the Thing to an external place such as a tent? If so, I have no such intentions. If you meant taking a gas heater and adding it to a '74, I may want to do that if I get a '74. Under such a circumstance, I would also add the ductwork the '73 had and have dual heat (so to speak) with a gas heater as one option and heater boxes as the other option. I have been taking note of another thread that has that possibility in the works.

Thanks again.

Worknclassbug Wed Feb 02, 2011 7:08 am

Worknclassbug wrote: We finally had a day above freezing here and I took advantage of it to work in the garage. I got a new (used) exhaust pipe and some other parts for my heater and installed them and fired up the heater for the first time. After I let it run for a few minutes with the fuel line off to get gas pumped up to the end of the line I connected the fuel line and the heater fired right up and ran great for about a minute and then I could hear the flame kind of intermittently going out for a second or two. Then after a couple of minutes the safety relay tripped and the heater stopped. I reset the relay and the heater restarted and was still having intermittent flame outs every few seconds and the safety relay tripped again. Is this possibly because of air in the line and is the safety relay tripping because the chamber isn't getting up to temperature? I'll try to let it run tomorrow with a clear fuel line on it so I can watch for bubbles.

In case anyone is interested, I was getting a lot of air bubbles. I only put about a gallon of gas in the tank to begin with and I think that was the culprit. I filled the gas tank about half full and let it sit for a while to work out the air that was trapped in the new fuel filter. I tried the heater again and it worked great. Thanks for all of the advice.

nateairman Thu Mar 17, 2011 6:40 pm

I am in the process of repairing a BN 4 and have a few questions:
1. What do I replace the braided lines with?
2. There seems to be a bit of the fan missing and it vibrates slightly. Is it balance able? I had to put new bushings in the motor....

Great thread Thanks to everyones input!

fyter889 Mon May 16, 2011 1:10 pm

a separate pressure regulator. Ok heres my problem, fuel pump inop, got 12v there, has been dissassembled cleaned etc. My question is, does anyone know what the fuel pressure is supposed to be going into the combustion chamber? I am looking at several types of pumps to try to update this unit a little. I see on some of the posted photos in this thread that there are no pressure regulators on those heaters, mine sits just aft of the intake fan forward of the coil and plugs on the outside of the main body. Any help would be appreciated. BTW this unit does run if I manually run the points on the back of the pump.

analogmax Sat Nov 05, 2011 11:09 am

my fuel pump was not working at all, I had voltage but no click. I pulled it and cleaned it but still no good. I ended up spraying some carburetor cleaner in it and the next day it was working great.

jwillhoit Tue Nov 22, 2011 4:16 pm

I'm looking for a someone to rebuild my BN4 gas heater. If anyone knows anyone that offers this service, please let me know. Thanks

Captain Spalding Tue Nov 22, 2011 6:20 pm

jwillhoit wrote: I'm looking for a someone to rebuild my BN4 gas heater. If anyone knows anyone that offers this service, please let me know. Thanks
Give Greg and Arda at German Motor Works a call. I bet they can do it for you. They're in Garden Grove. (714) 534-1841



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