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  View original topic: Heating FAQs - BN4 Gas heaters & heating related topics Page: 1, 2, 3, 4, 5  Next
Fun 181 Thu Dec 11, 2008 3:27 pm

Heating issues are a popular topic here in the Thing forum, especially for the owners of '73 Things. Below is a list of previously posted links to topics relating to heating issues with the BN4 gas heater which you may find helpful. I have also listed some information and photos regarding heating for the 1974 model Thing as well.

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1973 Thing BN4 Gas Heater FAQs
Note that the majority of these posts deal with similar BN4 heater issues so there is a LOT of information overlap. However, each post may contain unique information which you may find to be helpful.


Here is the owner's manual page...



Here is a photo with captions of the BN4 heater switches courtesy of Captian Spalding...

Captain Spalding wrote: Better than a thousand words:



I'm not sure where to get the switches. They are becoming more and more rare. Try the usual suspects: Samba classifieds, German Motor Works, Thing Shop, Kubelmann, etc. The timer switch will be easier, it's the thermostat cable that might take some hunting. Don't be discouraged though. When the BN4 works, it works GREAT!

Here is a BN4 wiring diagram...


The BN4 VeeWiki Page
Ian Epperson has created an overview of the parts and operation of the BN4 heater on his VeeWiki page which is a great place to start...
http://veewiki2.webfactional.com/HeaterBN4

VW Workshop Maual: Fresh Air Heating
"This manual covers Eberspacher gas heaters installed in several types of air-cooled Volkswagens. These units are relatively unsafe if not well looked after, so hopefully owners of these heaters will find this information useful."
Found here...
http://oacdp.freeweb7.com/ebersp.html

Bn-4 heater step by step
A detailed thread which uses photos and labels to help explain the inner workings of the BN-4 heater. A great aid for performing maintenance...
http://www.thesamba.com/vw/forum/viewtopic.php?p=3738099#3738099

BN4 Gas heater question: carbon deposit on plug prevent fire
Topic discussing plug gap specs and issues with fouled plugs...
http://www.thesamba.com/vw/forum/viewtopic.php?t=331023

Please one more bn-4 question?
Taking apart the heater and performing maintenance on/gaping the points...
http://www.thesamba.com/vw/forum/viewtopic.php?t=351234

Another Heater question
A topic regarding general maintenance, fuel lines, electric pumps and filters...
http://www.thesamba.com/vw/forum/viewtopic.php?t=330983

73 Thing-gas heater - wiring
Questions and answers about the BN4 wiring with diagrams and photos...
http://www.thesamba.com/vw/forum/viewtopic.php?t=349323

Looking for BN4 glow spark plug '411 963 319' part
Where to find the proper glow plug - includes photos...
http://www.thesamba.com/vw/forum/viewtopic.php?t=327036


Heater (fuel pump) question
Trying to get another BN4 up and running - unresolved...
http://www.thesamba.com/vw/forum/viewtopic.php?t=326139

Source for Gas Heater Rebuilding
Please note that "Heaterman" who was once a reliable source for rebuliding gas heaters is now MIA. Several other sources are mentioned...
http://www.thesamba.com/vw/forum/viewtopic.php?t=279187

Heater blowing fuse
Regarding fuses for the fuse block and the heater itself...
http://www.thesamba.com/vw/forum/viewtopic.php?t=320611

1973 Thing Heater Pictures
"I like looking at the pictures"...
http://www.thesamba.com/vw/forum/viewtopic.php?t=317115

73 Heater question
Questions regarding the details and dimensions of the BN4 exhaust pipe - lots of photos...
http://www.thesamba.com/vw/forum/viewtopic.php?t=196362

Another Gas heater problem
An in-depth discussion regarding fuel pumps and fuel flow...
http://www.thesamba.com/vw/forum/viewtopic.php?t=261126

heater question...cold out!!
Possible thermostat issues - great info but maybe unresolved...
http://www.thesamba.com/vw/forum/viewtopic.php?t=281962

Gas heater priming
Priming issues...
http://www.thesamba.com/vw/forum/viewtopic.php?t=268527

Gas heater paint color?
In case you want to paint your heater...
http://www.thesamba.com/vw/forum/viewtopic.php?t=273719

Propane Thing Heater
An interesting discussion involving safety for this heating alternative...
http://www.thesamba.com/vw/forum/viewtopic.php?t=332062

And lastly we have...
The Life and Death of a Gas Heater
This is a very old thread from 2004 found on ShopTalkForums, but it contains a lot of helpful information...
http://www.shoptalkforums.com/viewtopic.php?t=80886

A few more detail photos of the BN4 gas heater from the Thing Gallery...

Note, if anyone can submit better (more in focus) photos of the wiring on the heater itself I will replace these...



Here are two photos showing two different Eberspächer heaters.
Top: Eberspächer BN 4
Bottom: Eberspächer B1 LC
Again, thanks to Captain Spalding for the photos.


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1974 Heating FAQs


Heater Boxes/ exchangers
A topic dealing with the heater hoses that connect the fan shroud to the muffler...
http://www.thesamba.com/vw/forum/viewtopic.php?t=321077

heat ducts
A thread by "mstatedog" detailing his efforts to custom fabricate metal ductwork on his '74...
http://www.thesamba.com/vw/forum/viewtopic.php?t=148971
(check out his gallery pics for more photos)

Diagram of the ductwork...



Photos of stock '74 duct work courtesy of emersonbiggins...





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I hope you'll find this info helpful. I'll update this as more info becomes available.

- Slim

*** Note: I've asked Everett to make this a sticky thread.

crofty Thu Dec 11, 2008 3:35 pm

I second your request for sticky status!

amishman Thu Dec 11, 2008 3:45 pm

crofty wrote: I second your request for sticky status!

I 3rd it. :lol:

Now that I am working on cleaning and installing my hardtop, and maybe use my Thing in winter, I will need to work on the heater, as I have no clue if mine works.

tj

oasis Thu Dec 25, 2008 7:17 pm

Can a gas heater be made to work in '74 (and later) Things? I'm not limiting my question just to the BN4. If the answer is yes, what should one do to delete the heater boxes ... or should they be kept as a second heat source?

Ferretkona Thu Dec 25, 2008 8:28 pm

oasis wrote: Can a gas heater be made to work in '74 (and later) Things? I'm not limiting my question just to the BN4. If the answer is yes, what should one do to delete the heater boxes ... or should they be kept as a second heat source?
Yes.
I am adding a BN4 to my 74 bonnet.
I currently have no heater boxes, but I will be replacing them when I get around to buying them. I have no problem running two heating sources.
I have a BN4 in a box and I am ready to cut out the holes to add it. The only thing I am missing is the fuel pump.

oasis Fri Dec 26, 2008 7:59 pm

Ferretkona wrote: I am adding a BN4 to my 74 bonnet...I have a BN4 in a box and I am ready to cut out the holes to add it.
Are these holes already existing in a '73? Will you have the ability to switch back and forth with the defroster on? Will you also be using the timer switch from a '73?

Thanks for your answers. (Perhaps a tutorial would be a nice addition to this sticky. 8) )

Ferretkona Fri Dec 26, 2008 9:02 pm

oasis wrote: Are these holes already existing in a '73? Will you have the ability to switch back and forth with the defroster on? Will you also be using the timer switch from a '73?

Thanks for your answers. (Perhaps a tutorial would be a nice addition to this sticky. 8) )
The holes are not in the firewall or fender, but they are on a 73. I have pictures of the locations and will use a holesaw to drill them out. The exhaust exits thru the inner fender behind the tire. I have a new timer switch (NOS) on hand.
I do not know if I will use the BN4 for the defroster yet. The ducts from the heater boxes are intact so I may just use them.

doublecanister Wed Jan 21, 2009 11:18 am

Hey everybody,

Just curious on these gas heaters, BN4 Eberspacher type;

I've gandered at the presented information and THANKS for making it available, i've learned a few things so far, but...

Does anybody know if there is a walkthru test document (flow chart style) to test these heaters?

As I am studying up on them; I was curious if there exists a troubleshooting document of flow chart design, something a tad bit more user friendly than what i've seen.
I know some places sell heater repair books, but I didnt want to buy one thats equal to the shop manual I already have.

Any suggestions or links to anything anyone??

Some folks have reccomended the RoMToC cd & I have found some links with this forums links on a Canada Only troubleshoting guide (that wasnt too difficult to follow), just hard to read due to quality of scan and appeared difficult to print in a usable format.


My heater status:
Currently, if you pull the thermostat out, turn on the fan, I get a clik and the fan runs & thats it, (sounds like the fuel pump clicked but cant tell for sure) I've read the fuel pumps may take a whack or 2 to start, & I would need to check for pulse 12volts at the pump, and to check the relay hasn't tripped.
Other than that, it appears to be a technical nightmare to troubleshoot these heaters. So far, I noticed my heater is a under 10k serial # in the 9k range, and looks like its never been used.

I hate working on objects i know little about, I wouldnt want to damage anything or set the THING on fire, but a little more 'user friendly' troubleshooting documentation would be a great idea....
Anyways, Just thought I'd throw it out and ask everybody, I may be wishing for somthing that doesnt exist, but you dont know till you ask.

Thanks All for any info and sorry for the rant....
I wanna drive my THING and its too freakin cold!!! :cry:

T.

Fun 181 Thu Jan 22, 2009 9:29 pm

doublecanister wrote: Hey everybody,

Just curious on these gas heaters, BN4 Eberspacher type;

I've gandered at the presented information and THANKS for making it available, i've learned a few things so far, but...

Does anybody know if there is a walkthru test document (flow chart style) to test these heaters?

As I am studying up on them; I was curious if there exists a troubleshooting document of flow chart design, something a tad bit more user friendly than what i've seen.
I know some places sell heater repair books, but I didnt want to buy one thats equal to the shop manual I already have.

Any suggestions or links to anything anyone??

While I was researching BN4 heaters I don't remember coming across any troubleshooting guides in a flow chart format. If no one posts an answer here I would suggest PMing/emailing your questions to either Capt. Spalding, Ian Epperson, Crofty, dan macmillan or Mike Basso ([email protected] ). These guys seem to be pretty knowledgeable about the Eberspacher, and can probably answer any technical question you may have.

Good luck,
Slim

crofty Fri Jan 23, 2009 12:21 am

I'd clean all your grounds, flip the red emergency switch a couple of times and pop the top off of the thermostat switch to make sure everything looks ok in there. They can get moisture in them and corrode a little.

Also a PITA but changing the fuel lines (and adding clamps) is a must if it hasn't been done in a long time.

doublecanister Sat Jan 24, 2009 6:16 am

Hey Crofty and Fun181, after a bit of digging I again found the link to the flow chart troubleshooting guide (that says canada only).

I Also noticed it says :Troubleshooting Guide: BA-4 Gas Heater: (not BN4)
so I probably found somthing I cant use. (just saw that, oops)

http://oacdp.freeweb7.com/ba4.html

Others here: http://oacdp.freeweb7.com/docproject.html

I ran across them using the links in this sticky, somehow.

What do yall think? (of this canada flow chart ts guide??)would it be of any use??
I guess if its an entire diff model heater, prob not best to use these inst,
Oh, I thought I struck gold on this one. RATS!

But, I appreciate your input, I will try what you both reccomended. Thanks again guys! I'm gonna get this dern thing working somehow.

Be Good!
T.

[email protected] Sat Jan 24, 2009 6:49 am

http://www.thesamba.com/vw/archives/manuals/bn4troubleshooting/2.jpg
and http://www.thesamba.com/vw/archives/manuals/bn4troubleshooting/3.jpg

These two pages will help with troubleshooting.
The fuel pump wont click unless the contact inside the brass box is making contact. if it doesnt or wont. you can temporarily override the safety device by jumping the two blue wires together dont leave it like this
If you still have trouble, you should make sure you dotted your is and crossed the ts and get on the phone with me, while you are next to your car. and I will try to help. Mike

alex1916v Sun Mar 01, 2009 11:44 am

hi there, been thu most of the info on this thread, VERY helpful!!!

just one minor question....

i cant find any details regarding the wiring up fuse board end.... heres my problem.....


my military trekker has 2 fuse boards, curently theres only the big red from the starter motor doign anything on that 2nd fuse board, so off the big white plug for the heaters wires it goes into the fuse board but dosnt connect in the board where any power is....



ive got the big red one going to the first fuse on the right on the 2nd fuse board, this is the main live one, this has 2 fat red wires going off to power the normal 1st fuse board for all the other standard wiring lights etc....

then ive gotta connect the smaller black wire to the 3rd terminal along on the 2nd fuse board,... thats all fine but at the moment ive got nothing going in or out of that fuse board other than the main live...



this is how my 2nd fuse board looks, except now its got the far red going to the 1st fuse, where them big red's are going in etc...

has anyone got any info one this? im gonna go have a look for a colour wiring diagram for the military style trekker, because i went off of a civilian trekker wiring diagram for all the rest...

also does it matter which way round the fuel pump terminals are wired? im guessing if its incorrect it'll pump the wrong way?? there are no markings, on it..

the wires ive got are a brown and a green, as per drawing... ive just put em on at the mo, i can swap em...

Also, once i have this thing wired up, and ive connected the fuel line, whats the correct method of ignition??

im guessing i turn the green 'egg timer' knob on the dash, then wind it a little, then it should fire? what about the first time, ie should i try and bleed the fuel to the pump, or with it be fine pulling it thu the lines etc?? also ive got a 'choke' style knob, which i guess you pull for more heat?? can i pull this straight away???


So has anyone got any pics off the 2nd fuse board in situ with that dash panel flipped down, one pic showing where the wires are coming and going should help me out no end!!!


cheers for any info!
alex

Saturnin Sat Oct 24, 2009 5:59 pm

Hello-- can someone tell me how this flat copper piece showed on this photo is called and where I can find a replacement? Mine was repaired but broke again... Thanks! Paul


http://i392.photobucket.com/albums/pp7/paulvw181/IMG_5269.jpg

[email protected] Sat Oct 24, 2009 6:25 pm

I have some Pmail me, Mike

xavi_242 Thu Dec 10, 2009 1:30 pm

alex1916v wrote:
my military trekker has 2 fuse boards, curently theres only the big red from the starter motor doign anything on that 2nd fuse board, so off the big white plug for the heaters wires it goes into the fuse board but dosnt connect in the board where any power is....

So has anyone got any pics off the 2nd fuse board in situ with that dash panel flipped down, one pic showing where the wires are coming and going should help me out no end!!!

cheers for any info!
alex

have the same problem right now... the big red was not in place and now I don't know where to connect it... :S


crofty Mon Jan 04, 2010 8:49 pm

xavi_242 wrote: alex1916v wrote:
my military trekker has 2 fuse boards, curently theres only the big red from the starter motor doign anything on that 2nd fuse board, so off the big white plug for the heaters wires it goes into the fuse board but dosnt connect in the board where any power is....

So has anyone got any pics off the 2nd fuse board in situ with that dash panel flipped down, one pic showing where the wires are coming and going should help me out no end!!!

cheers for any info!
alex

have the same problem right now... the big red was not in place and now I don't know where to connect it... :S



Where's the wire from the other side of the red wire coming from?

xavi_242 Fri Jan 29, 2010 4:35 am

forgot to say that the heater runs perfect now. just connected wires and replaced fuel lines and filter and some hammer knocks at the fuel pump that was stuck.

Captain Spalding Wed Feb 03, 2010 11:50 am

A PDF service manual for the BN-4 is now available in the Technical Section.

http://www.thesamba.com/vw/archives/manuals/thing.php

Emeritusx Sat Mar 27, 2010 7:51 am

For what its worth:

My heater was only working sometimes. And failure to light was becoming more and more a problem.

I took my battery charger and hit On side of the fuse, fan speed up, heater lit.

Took the charger off and hit the other side of the fuse.. No speed increase or anything. Cleaned the fuse ends and bang first time everytime..

BTW is the fuse bypassed in that picture ^^^^ ?



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