"Engine Preheat" vs. "Engine Heater"

[Pete Masterson]

After some experimentation today, I found that the pre-heat switch
does _not_ start the AquaHot unless the "Hydronic Heat" switch on the
dash is also _on_. (Another person said it worked with the Hydronic
Heat switch either on or off...)

Now, I'll have to run a longer experiment and feel around the various
pipes and connections to find out what goes on or not. <sigh>

From past experience, I've learned that what BB did on one coach may
not have been done on any others -- or may be a "standard" for all.
I'm going to guess that the dash heater valve thing might be an error
on your coach only ... but I'm turning on the dash heater lever right
now just to be sure!

Pete Masterson
'95 Blue Bird Wanderlodge WBDA 42
aeonix1@...
On the road at



On Oct 22, 2007, at 3:38 PM, martingregg598 wrote:

> Hi Pete, on my 95 BMC 37' the Aqua Hot engine preheat loop runs
> through
> the dash heater core, so if I have the dash heater, hot-cold lever in
> the cool position the valve is closed and the hot engine coolant
> coming
> through the Aqua Hot to the dash heater can't pass through back to the
> engine, no loop. I discovered this one day when I had the A/H engine
> preheat on and I was playing around with something under the dash and
> felt the hot line on one side of the valve and cold on the other. I
> can't help but wonder if the installers at BB put all of the A/H
> plumbing in the same way? My instruction manual says not to have the
> A/H engine preheat on while the engine is running. Good Luck.
> Marty Gregg
> 95 BMC 37
> Kennewick, WA.