BN4 Start-up Dangers?

[davidw99]

Hello all,

I'm thinking of buying a 73 Thing. The owner says the heater is installed and looks good but hasn't run it. Are there any issues I need to be concerned about before trying to start it? For example, is there a danger of it exploding or bursting into flames? Are there any other issues that I should be concerned with on first start? I hope I don't sound paranoid but since I don't have experience with gas heaters I want to ask before finding out the hard way.

David
_________________
Dave

'73 Saturn Yellow Sports Bug that has undergone a full pan off restoration. "Herbert IV."

'67 Sedan. "Bellamy." Currently being "refreshed" and recently repainted.

[Wildthings]

Replacing the 40 year old fuel lines is always a good idea. These units don't sit well and give problems even when run fairly regularly, thus you will probably find lots of things not working which will take some effort to fix.

Some of the more common ones:

-The fuel pump is probably gummed up and will not pump at all
-The points for both the fuel pump and the ignition are probably corroded and need cleaning
-The cable for the thermostat is likely corroded in its sheath
-The thermostat itself is likely corrode and will not move or otherwise work


Good luck with getting your unit going.

[germanbilly]

Read this Sticky I used it before I fired mine up the first time after it had been sitting for 8 years and it worked perfect. Had to replace all the fuel lines and filter. Unstuck the thermostat and got thr fuel pump unstuck. Works perfect now.
GB
http://www.thesamba.com/vw/forum/viewtopic.php?t=332848

[davidw99]

Thanks all. I guess I don't need to worry about an explosion.
_________________
Dave

'73 Saturn Yellow Sports Bug that has undergone a full pan off restoration. "Herbert IV."

'67 Sedan. "Bellamy." Currently being "refreshed" and recently repainted.

[Wildthings]

[Captain Spalding]

While the workings of the BN-4 aren't intuitive, they don't have to be daunting. Many folks give up too soon and switch to heater boxes or some other option. But nothing else really compares to the BN-4 which will keep you toasty even in a drafty old car like the Thing.

Have a look at this diagram, which explains the relationship among all the heater components and explains the redundant safety features.

There's a wiring diagram for the heater here.

Heater instructions.

In rare circumstances, one of the heater components will need adjustment. Don't make adjustments unless all the more typical remedies have been tried, and only after you've done your homework.

Flame switch adjustment.

Overheating switch adjustment.

Fuel pump service and adjustment.

Safety switch adjustment.

Download the heater service manual.

[davidw99]

Captain,

Thank you. My father once told me years ago that gas heaters can explode. Or at least ignite the gas tank. Of course, this thought has stayed with me. Of course, also, I don't know what cars the heaters were on, who made them (or even if they were on cars for that matter but I assumed they were since we were talking about cars).

I have no intent of going to heater boxes. They work fine in my Super but I want to have this Thing working with the original heater system. I just didn't want any surprises if I flipped the switch.
_________________
Dave

'73 Saturn Yellow Sports Bug that has undergone a full pan off restoration. "Herbert IV."

'67 Sedan. "Bellamy." Currently being "refreshed" and recently repainted.

[Captain Spalding]

[IHC]

Sometimes on start up you also can get a large black and gray and very smelly exhaust cloud. Don't shut the heater off, it's just clearing out old fuel.After a few minutes it clears up. I have used the heater for 15 years I have owned my Thing without problems.

[Schwankster]

Don't give up on the gas heater, they work GREAT! I've found that I need to open the window to let in some cool air when I use my heater. Just the other day I got curious, and stuck a thermometer into the lower/floor air duct to see just how hot the air was. The thermometer was reading 255 degrees when the unit was in full operation, and it would cool down to about 185 before it would cycle on again and go up to 250+ degrees F. I always joked with folks telling them that I could roast chickens inside of my Thing with the heater on, and I guess I wasn't too far off! If I could add some smoke flavoring, I think I could make some tender BBQ in the Thing! I got lucky and the heater was working when I bought my thing a few years ago. The PO had never used it in the few years he had it, but it fired right up for me and has always worked well. I make a habit of turning it on at least once a month to let fresh fuel run through it for about 10 minutes.

[Captain Spalding]