From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: converting an rv furnace from LP to nat gas?
Message-ID: <foh8nu099920o4jiarfetupvdi54ck5bls@4ax.com>
Date: Tue, 03 Sep 2002 01:34:47 -0400

On 02 Sep 2002 15:57:59 GMT, wakka1a@aol.comDieSpam (Marc) wrote:

>THIS IS NOT A DO IT YOURSELF JOB !
>
>Some facts stated here are true :
>
>Yes - there are diffrent orifices for Natural gas then propane
>
>Fact - Natural gas appliances usually run at a lower pressure 3.5" as oppossed
>to 11" or so for propane.

6.0" h2o for natural gas and 11" for propane

>
>Fact - ( at least with residential equipment - not 100% positive about rv) Most
>gas valves are set either for 1 gas or the other & are not intended to be
>switched between gasses - exceptions would be stoves & clothes dryers - which
>are appliances that can be 'moved'.

Nope.  I've never run into a residential or commercial appliance that could
not be easily moved - and I've done dozens, probably hundreds.  Many, like
stoves have adjustable orifices and regulators.  Others require conversion
kits available from the mfr.  The kit typically contains a new (set of)
orifice, a new spring for the internal regulator or a spring spacer and a new
label.

>Fact - Air shutters ( if equipped ) will have to be reset for the fuel switch
>too.

BFD.  30 second job.

>
>For safety - this is 1 operation best left to a pro.

This post is an example of why "pros" (defined as anyone who straps on a work
uniform with his name over his pocket) get it wrong as often as not.

The reason why converting an RV furnace from propane to NG is very simple -
the appliance is approved only for use in RVs and RVs use propane.  Since
there is no market for a natural gas conversion, the kits are not available in
most cases.

Now one CAN do the conversion manually.  I've done several.  This involves
retuning the built-in regulator, if it exists, by changing springs or removing
spacers as the case may be, and drilling the orifice.  A set of orifice drills
and reamers are necessary - probably available from MSC or whatnot.  I've had
mine so long I forget where I got 'em.

The procedure is fairly simple - ream the orifice until the blue flame with
the proper A/F mix is approximately the same height as it was on propane.
It's easy to go too far.  The fire will burn OK but there is a risk of burning
out the heat exchanger or exceeding the surface temperature spec for the
furnace.  If you go too far, simply solder or epoxy up the orifice hole and
start again.

This works best with pilotless ignition systems, as the tiny pilot orifice is
effectively impossible to drill.  A new NG pilot assembly could be purchased
and installed.

Frankly, for an RV I wouldn't fool with all this trouble. I'd either install
an external mobile home furnace/AC or use nonvented gas or electric heaters.
A small mobile home AC/furnace is probably the best solution.

John

From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Natural gas to LPG
Date: Sun, 08 Jun 2008 01:49:41 -0400
Message-ID: <ugsm44de0reqton681v5a9rfbotv5mj3om@4ax.com>

On Fri, 06 Jun 2008 12:01:07 -0500, Art Todesco <actodesco@yahoo.com> wrote:


>> You have an idiot for a neighbor, does he like paying for gas that
>> he's not burning? What he does burn it probably not as evvective as it
>> could be since the carbon deposit is insulating the inside of the heat
>> exchanger.  Most appliances require an orfice change while some you
>> can just screw the orifice in or out depending upon the change. ( This
>> is mostly for gas stoves.
>>
>>
>I agree 100% .... but when you have
>financial problems and gas gets
>turned off, you do what you have to.

True.  But "what you have to do" in my book, at least, is to fill the orifice
in with epoxy or solder and drill a smaller hole.  It may take a couple of
tries to get it right but once it IS right, the appliance works properly and
economically.  In either case, when the gas comes back on, the filler can be
removed with heat to return the appliance back to normal.

I've converted MANY NG burner to propane using just this technique.  It's
easier and less hassle than trying to track down the exact model number and
then figuring out where to get the conversion kit.

John