zero wrote:

On Sat, 05 Aug 2006 22:16:34 GMT, "Pete C."
wrote:

John wrote:

"Pete C." wrote:

trimmed
The owner was also directed to have the boiler serviced as soon as possible.

That is / was *not* an explosion, not even close. I don't think a
blowback on a residential boiler has ever injured anyone, much less
killed them. Certainly it will scare the **** out of them and perhaps
teach them not to keep messing with the thing if they don't know what
they are doing.

Oil burners do *not* have blowbacks on their own, they have had the
safety devices to prevent that for decades. Blowbacks occur when someone
keeps pressing the reset button ignoring the warning not to press it
more than once. Oil burner controls from the last couple decades have
incorporated a "three strikes and you're out" lockout to prevent this.

Ok, that's not the case. You can reset ANY oil flame safeguard
relay control as many times as you like.

One of many examples:

http://www.carlincombustion.com/products/50200.htm

"Serviceman Reset Protection ( Latch-up after three consecutive
lockouts)"


The nucleus of gas vs. oil residential heating safety lies in the
control methodology of the times.

Oil burners are direct fired. The full fuel output is ignited by a
strong arc. There is no pilot light. If it does not ignite, there is
approximately 10 seconds worth of atomized oil spray
inside of the combustion chamber. Flame detection is performed by a
Cad Cell.

Right, but what does that have to do with the three strike lockout?


Until recently, most all gas furnaces used a small pilot light to
achieve combustion, which in turn ignites the main burners. More of
today's furnaces are direct light off such as the oil burner, however
modern flame safeguards strategies are applied to bring an acceptable
level of safety to the gas burner.

If you're indicating that gas burners until very recently have had very
minimal controls with limited safeties you are correct. Many had no
electronics at all and relied on a thermocouple heated by the pilot as
the only safety for pilot loss. Most had no detection if the main burner
actually lit off properly. Most had no easily accessible emergency off
switch, you had to find the gas valve, etc.


There are better controls available for domestic oil burners
however they have not found their way into the residential product
lines.

Huh? Those features are on nearly every residential oil burner
manufactured in the last decade. They are certainly on the oil burner I
had installed this spring.


Proportionally, there are many more instances of delayed ignition in
oil, then fuel gas.

For pilot units probably. And for delayed ignition on an oil burner
rarely anything of consequence without human intervention overriding the
safety.


So oil heat is not "safe" under your definition.

http://www.newburyfd.org/responding_...er_emergen.htm

That is an interesting link however you probably didn't read it
thoroughly:

This other bit:

"Fuel oil comes in several grades, number 1 to 5 grade oil, and has the
following general fire hazard properties: a flashpoint of 1007F to
1507F, a flammable (explosive) range of 0.7 to 5 percent when mixed with
air, and an ignition temperature of 4947F."
should give a bit of a reminder on just how difficult it is to get oil
to burn and the near impossibility of igniting oil spilled from a tank
leak.

Oh it won't burn pretty, but it WILL burn under far less stringent
conditions as these.

Yea if you get it on a wick and apply direct flame to it to get it
started ala oil lamp. An inch of oil across the basement floor has
little chance of ignition even if there were a burning pilot light
nearby. In the very unlikely event the oil level to make it to the pilot
light there is near 100% probability it would simply extinguish the
pilot. Nat. gas (or propane) if they leak and build until they are in
proximity of a pilot have a near 100% probability of exploding.

Pete C.