Date:         Sat, 27 Nov 2021 08:23:59 -0500
Reply-To:     Derek Drew <derekdrew@DEREKMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Derek Drew <derekdrew@DEREKMAIL.COM>
Subject:      Backwards Flow Through Heat Exchanger OK?
Content-Type: text/plain; charset="us-ascii"; format=flowed

Is the heat exchanger in the heater box indifferent to which hose is
hooked up in the forward/lower position and the rearward/upper
position in the heater box?

The reason I ask is because I was looking at a (excellent) GoWesty
repair video for the heater box and it shows them starting off with
the hose that enters the vehicle in the floor on the passenger side
("Right side") going through a clamp next to the heater box and then
gong to the "TOP" (rearward) position in the heater box, what we
could call CONFIGURATION A. Some text in the video emphasizes the
same thing, saying "Rightmost=Top" and "Leftmost=Bottom" for our
CONFIGURATION A. But then at the end of the video at 12:46 as they
are finishing up they show the configuration the other way around
with the hose entering the floor on the "Right Side" (passenger-side)
going through the clamp and then to the lower (forward) hose
connection on the heater box, what we could call CONFIGURATION B.
Their video which shows the hoses connected first one way, and then
the other way, is here: https://www.youtube.com/watch?v=h7wgsznvcCE

Then I looked in one of my syncro campers ('91) and the last mechanic
hadn't hooked up the hose clamp to the frame at all, which suggested
to me I had resolved why I could not close the glovebox after that
service. It was while trying to figure out the hose clamp
configuration that I noticed the discrepancy in the GoWesty video
about which hose gets clamped to the huge frame cross member on which
the heater box sits.

Then the plot deepened because I noticed that my van had
CONFIGURATION B where my "Right Side" (passenger-side) hose was also
connected to the lower (forward) hose connection on the heater box,
as Go Westy did at the end of their heater box video. At this point,
I paced around in the garage for a moment and had strong WTF-type
feelings for a second.

I then noticed a great UK video equivalent to the Go Westy video from
(adorable?) ItalJohn here:
https://www.youtube.com/watch?v=DozqP2ADdHw His hoses were hooked up
in CONFIGURATION A (ref 5:31).

So, I suspect that with configuration B my hoses are hooked up
backwards to the heat exchanger. A question is whether I should
create a little coolant mess in the van and fix this or whether the
heat exchanger really doesn't mind what direction the coolant is
flowing through it.

I could not think up a search query to resolve this, although I did
find some wishy washy suppositions that maybe the heat exchanger
doesn't care about the direction of flow.


_______________________________________________
Derek Drew
Sharon CT
derekdrew@derekmail.com
Email is best normally but...
Mobile: 703-408-1532 (voice and texts)