Date:         Tue, 24 May 2011 22:52:13 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Fwd: Westfalia refrigerator issues
Comments: To: mcneely4@cox.net
In-Reply-To:  <20110524200756.MINN0.552688.imail@eastrmwml32>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 08:07 PM 5/24/2011, mcneely4@cox.net wrote:
>Hmmm.  My camper is a '91, the latest model imported.  I thought I
>was, with the pump, operating both air and piezo ignition.  I have
>had the refrigerator out and cleaned it.  (Nasty job getting it out
>and back in ok), but that was two years ago, and I just don't
>remember everything perfectly.  If the ignition is not piezo, what is it?

Ok, you had me fooled with reference to the igniter button.  There
*is* an RM182C (I've never seen one) with electronic ignition; I'm
not familiar with its precise details.


>My led doesn't tell me whether the burner is burning until I stop
>pumping and release the button.  Then it lights up (it has always lit).

There are four operations involved: purge the combustion chamber,
spark, hold the gas valve open with the button, hold the gas valve
open with the thermocouple (and incidentally light the LED).

In theory you purge first (pump five times) then spark once or more
until you see fire, then continue holding the button down for thirty
seconds while the thermocouple takes over - just as you would when
lighting your water heater or furnace at home.  In practice I
certainly always found it convenient to spark at the end of each pump stroke.

Your specific way of operating has turned up the fact that at least
on your fridge/LED panel combination the thermocouple can hold the
gas valve open before it can light the LED.*

*This is a slight misnomer.  Not in a thousand years could the
thermocouple light an LED.  But it's hooked to the input of an
amplifier in the LED panel and the output drives the LED.

Trivium:  The thermocouple signal is the only voltage in the van that
drives negative to chassis ground, and the designers of the LED panel
took advantage of a specification in the chip that allows its inputs
to go 0.3 volts below the negative supply voltage.

Best.
d