Re: OT: RV furnace help needed

In article
<855e847c-9ada-47cd-ad3f-f432b157bcff@xxxxxxxxxxxxxxxxxxxxxxxxxxx>,
"Whelan - '02 200exc (x2) & '04 MTD 38" <yosef@xxxxxxxxx> wrote:

I have similar problems with my furnace.

I was hoping you'd see this :)

What exactly is the problem you're having? I'm fairly confident mine
is temperature-related, rather than a mechanical problem (e.g.
hairball gumming up the sail switch). If it was a sail switch problem,
the furnace wouldn't work at all. Mine seems to only fail when the
temp. drops below 40°F or so.

It never occured to me there
might be something foreign in there preventing the sail switch from
operating properly. When the snow melts, I think I'll try blowing
some 100psi air through the outside (intake/exhaust) openings & see if
maybe that frees it up.

Some of the guys I camp with are of the opinion that the forced-air
propane furnaces built into RVs are too inefficient. Two of them have
installed catalytic-style propane heaters in their rigs and are VERY
happy with that setup as it uses a fraction of the propane & doesn't
deplete the batteries with a fan. It also doesn't keep waking them
up.

Interesting.

There is some information from the mfr. related to temp. related
failures that imply a connection with LPG being ineffective at low
temps. I don't remember enough (!) of my organic chem. and
thermodynamics to grok how that can happen.

A furnace is a consumers friend when the outside
temperature gets colder. Unfortunately though, cold is an
enemy of LP gas. The BTU capacity of LP per volume
decreases as the outside temperature gets colder. Therefore,
based on how full the LP tanks are, the ambient temperature
outside and how many BTUs the furnace is, there may not be
enough gas to sustain ignition on the furnace.
Using the charts below, lets say that a 40,000 BTU furnace
wont fire up, and we also know that the 65 lb. LP bottle on
the RV is 40% full and it is 0 degrees F. outside. Ones first
thought might be that the burner or valve is bad. However, if
we use the chart, the vaporization capacity of the tank in
these conditions is only 38,500 BTUs. The furnace is not
going to perform very well because there is insufficient BTU
capacity in the tank.
If you were to put an insulated fire resistant blanket over the
tanks and a 75 watt light bulb under that, you would probably
raise the temperature of the bottles 10-20 degrees and
almost double the BTU capacity of the tank. This in turn
would allow the furnace to operate properly. So keep in mind
that a furnace problem is not always a component problem.

I THINK what they're saying is that the furnace just won't heat the
space very well, not that it won't ignite the propane.

Deeney? Where is vlj when you really need him...?

--
Charles
'99 YZ250
.

Relevant Pages

  • Re: OT: RV furnace help needed
    ... decreases as the outside temperature gets colder. ... enough gas to sustain ignition on the furnace. ... Using the charts below, lets say that a 40,000 BTU furnace ... Propane turned on to pilot circuit. ...
    (rec.motorcycles.dirt)
  • Re: Furnace install Questions
    ... estimates on replacing my 50 year old 90,000 btu furnace for my 1500 ... so I am going with the installer that I trust the most ... for the hot water heater exhaust. ...
    (alt.home.repair)
  • Re: Furnace Installation....Reasonable price???
    ... The salesperson mentioned that for our house ... > go to the next higher BTU unit. ... >> our 20 yr. old furnace. ... In my home I removed a 80,000 BTU and put in a 60,000 BTU Ruud mod. ...
    (alt.home.repair)
  • Re: Old Vigor Burnout Furnace adapted to heat treating
    ... Did you get a burnout furnace, ... I have a Robertshaw "infinite" controller for sale cheap... ... the controller and the SSR. ... track the cooldown temperature without having to reset it to cool down. ...
    (rec.crafts.metalworking)
  • Re: Temperatue setting during long winter vacation
    ... the furnace ON while we're away. ... temperature could be below -30C. ... in the basement including water heater and softener. ... You will also want to check with your insurance agent/broker. ...
    (alt.home.repair)