Re: [A/S] Thermasan on ebay

["d & b " <dtbw_1999@xxxxxxxxx>]

As I wound up with BOTH of the unopened ThermaSan units, I thought I 
would weigh in on this thread (the seller only put one up for bid, 
but there were two..the second unit will be for spares as Thetford 
has no parts left). The units were the model designed for trailers 
drawing from a black water tank only. The seller found them at an 
estate sale of a former Airstream repairman. As was advertised, the 
units were absolutely new, never been opened (everything still in 
original plastic bags, packaging).  The technology was rock solid, 
very conservative and the units have FULL certification by the 
National Sanitation Foundation ... each component carries a 
serialized certification seal. The units do NOT add any EPA 
controlled emissions to the exhaust stream and other than an simple 
injector tube located after all the cats and sensors, there is no 
change to the tow vehicle. The original speed sensor will NOT work on 
modern transmissions as new vehicle transmissions send electronic 
signals to the speedometer while the old trannys had a cable going to 
the speedometer (which the ThermaSan used), but everything else will 
install and function on a modern vehicle.  I am a EE, so creating a 
substitute for the speed sensor will not be all that difficult 
especially since all it did was make a connection to the vehicle 
12volt ground at speeds above 30 MPH.  Despite the ad claims about 
the "solid state controller" there are NO electronics in the system 
other than in the tank level sensor and that is very low tech by 
todays standards (and that sensor is just to let the driver know that 
the tank is empty as the pump is designed to run dry indefinately).  
The control unit logic is based on simple 12v relays.  The pump motor 
is actually a robust windshield wiper unit (recognized it immediately 
from my youth).  The pump itself is very low speed design and works 
off of the same principal as medical pumps (just looking at the pump 
makes me believe that Thetford simply modified a medical pump).  I 
remember these units from my late teen years as my parents were 
Airstreamers at the time and this was the gadget to have (no they did 
not have one...too expensive).  The real killer for the ThermaSan was 
cost and the general death of RVs as a result of the "gas crisis of 
the 70s".  They ran about $700 + installation back in their day.  
They were very popular on the GMC motorcoach as GM installed them 
from the factory.  The injection point is AFTER all the cats and 
sensors...only the muffler exists beyond the injection point.  The 
system only pumps liquid, no paper or solids as there is a fine mesh 
stainless filter at the extraction point in the blackwater tank.  As 
for rust, modern exhaust systems are now stainless steel (at least on 
all my vehicles) so this is basically a non issue.  It should be 
noted that running 60MPH @ 12MPG you create roughly 25 gallons per 
hour of water vapor (basic chemistry).  The ThermaSan adds 2 gallons 
per hour to that, so the added amount is trivial.  The ThermaSan only 
injects after the exhaust temps reach normal and the vehicle is above 
35-40 MPH.  Exhaust temperature just after the cats is incredibly hot 
(remember the early days when grass underneath cars would catch fire 
from the heat of the cats...better insulation prevents that today 
even though the temps are even higher in the modern cats).  The 
ThermaSans were designed to take advantage of the the fact that temps 
just after the cats is high (yes, they specifically discuss 
installations in catalytic convertor equipped vehicles). The temps 
present are far in excess of what is needed to not only vaporize the 
liquid, but to crack the molecules and destroy all bacteria and such 
that might be in the stream.   I have full intentions of installing 
the unit on my 2002 Bambi LS and it's tow vehicle, a 2002 Ford Sport 
Trac. While there are many that would be scared sh*#less (pardon the 
pun) to install one of these, as an engineer and someone how 
understood the technology and the fact that these things really 
worked, I jumped at the opportunity to get a couple of brand new 
units and add this capability to our rig.

dtbw