Date:         Fri, 25 Oct 2002 10:52:44 -0400
Reply-To:     The Bus Depot <vanagon@BUSDEPOT.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         The Bus Depot <vanagon@BUSDEPOT.COM>
Subject:      Re: Aircooled Heat inline fan?
In-Reply-To:  <5.1.0.14.2.20021025082156.03fcb690@gemini.tntech.edu>
Content-Type: text/plain; charset="US-ASCII"

> I looked at the systems sold in the VW mags and then took a ride
> down to my local marine store. They sell the same blower for $18

> I have heard this: if you put a standard bilge blower in-line
> with the main heater tube to boost the air flow you will have two
problems.
>
> First is that the fan is plastic and will melt. In fact it states on the
> box that they are only rated for 176 degrees or so. As Stan mentioned the
> heat is MUCH hotter than that.
>
> Second is that the fan will be sucking on the heaters and pipes.
> That means if it is trying to move more air than the boxes and system can
> supply (fan is larger than it needs to be) it will suck outside air into
the boxes
> through the seams or any loose pipes. If there are any exhaust leaks then
> exhaust gets sucked into the system and pushed into the cabin. Carbon
> Monoxide poisoning.


Before I started the Bus Depot, I tried one of these inline heater fans in
my '76 Westy, but the results were poor.  Yes, it moved more air. But since
the air was sucked through the heat exchangers more rapidly, the air didn't
have as much time to heat on the way through.  The result: more air volume,
but since the air was cooler, little or no actual heating improvement.
Also, the blower (one specifically sold for this purpose, although as noted
it is basically just a marine bilge blower) did eventually melt from the
heat.

I then put a small BA4 (from a Type 4) gas heater booster inline.  This
noticably increased the heater temperature, but there was still not enough
air movement, so what came out was hot but not enough came out.  So I tried
another bilge blower, thinking that this time, with the gas heater booster
keeping the temperature higher, the air would still be warm even after the
blower made it pass through the system faster (unlike last time).  I don't
know what I was thinking.  It worked great for about a week, by which time
the heat from the BA4 turned the bilge blower into a melted mass of plastic.
If you think burning-off oil smells bad when it gets into your aircooled
heating system, try burning plastic!  In retrospect I'm only surprised it
didn't happen sooner.

I then located a used BA6 heater booster, which was the optional one used in
both later Busses and aircooled Vanagons, and put it in place of the BA4.
Bingo! What a difference!!  Instant, hot heat.  Better than any watercooled
car.  It was immediately obvious why VW chose these for use in later
aircooled vans; they work like a charm! These heaters can be hard to find,
and installation is not particularly easy because there are many parts to
them, but it's worth it if you can find one.

With regard to the comment about a bilge fan that sucks air into the heater
channels causing carbon monoxide to be sucked in, while I didn't notice
myself this it certainly does make sense.

Other options for improving the stock heater include carefully sealing every
seam in the heating system and adding insulation (basically making the
system airtight), which will improve the heating capacity noticably (but
still not always sufficiently for the coldest weather), or putting a cab
divider (i.e. clear plastic sheeting ;use multiple layers for better
insulation) behind the drivers seats during the coldest months and letting
the heater heat only the cab area (for which it is more than sufficient).
Of course the latter method can be quite cruel to any back seat passengers.
:-)

- Ron Salmon
  The Bus Depot, Inc.
  (215) 234-VWVW
  www.busdepot.com

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