Date:         Sun, 5 Nov 1995 21:15:18 -0400
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         smitht@jupiter.sun.csd.unb.ca (Tim Smith)
Subject:      Re: Tundra Toaster Heater and Propane Safety II

>     These applications also have a variety of interlockeded safety devices 
>     - so that if the exhaust or the make-up air flow is reduced or 
>     interrupted, the fuel safety valve shuts off the fire.             

Yup, they got that, 3 sensors!

>            questionable - Air flow will undoubtedly fall off as the 
>            battery's capactity is used up.  Worse yet - this happens on a 
>            rather unpredicable - not necessarily repeatable - basis. 

Yup, the airflow/pressure is monitored, and will shut-off propane when low 
battery occurs

>        3)  There are typically only 1 or maybe 2 small unpowered roof      
>            vents - not enough to handle a significant amount of air - and 

So crack a window, especially the louvered ones! At 160cfm it's going to be 
like a small tornado in there anyhow!

>        4)  Most importantly - just like a "free" lunch - There ain't no 
>            such thing as "perfect" combustion.  There is always some CO 
>            produced  - - and - - as the battery condition drops - and air 
>            flow is reduced - there will be more.  CO poisoning is 

Yes, I doubt the claims (97% was quoted) also!!  Beware CO.

>     We are always looking for a "better" way to do things.  And any time a 
>     "new" device comes to our attention we try to use it to solve 
>     problems.  But sometimes the ground has been trod before us  -  If 
>     these kind of heaters were appropriate for heating campers, they would 
>     be readily available at every RV dealer on the continent who was 
>     looking to make a few bucks.  And they would have been tested and 
>     certified for such use by the UL, the CGA, or other testing 
>     authorities.  The fact that they haven't been says someting.        

This one is, UL sticker attached. Point well taken though. It was NOT 
designed as an RV furnace, hence the manual controls.  It was designed as a 
space heater for alert people, read: cold but awake.  Drowsing by the heat 
of this may be bad for your health, CO wise.  For safety a reliable 10-15 
minute timer should be installed.
         At 160 cu.ft./min air coming in, it works out to under 2 minutes to 
completely change the air in a bus.  With the air at up to 700F you could 
get toasty fast, and shut it off. I don't know what the ratio of fresh to 
combustion air is, likely a lot of fresh air coming in.  Unlike the VW 
heaters, if the flame goes out and the propane shutoff fails it would be 
blowing air/propane into your bus, scary connotations "Honey, I need a 
smoke...".
          As a substitute for an older VW gas heater to take the chill off 
in the AM it seems ideal, I never sleep with VWs heater running either! The 
BN-4 loaf heaters with the air pickup in the rear spare tire well can 
recirculate/build their CO etc. if the burner core is rusted through, 
despite the outside vent, beware!!

Tim Smith,  eternally yours,  cough, gasp,  in eternity... aawwwkkk, thump.


and ps: I don't own shares in this company!!!