Lennox furnace issues

[cofee_iv]

I have a Lennox furnace that is about 9 years old. It is a C23-41W, elite series. A couple years ago, it quit during -13 temps. A friend came over who is technologically savvy and somehow managed to get it running after 3 hours and lots of research. It quit again last winter in similar weather and has been off ever since. Today is rather brisk at eleven degrees and I'd really like to get it going again.

It is propane. The pilot is not on. I have turned it off and waited hours before trying to turn it back on. Nothing. Any ideas would be very helpful. Thanks!

[dkpd1581]

You may want to check the pressures of the gas in your supply tank and at the inlet side of the units gas valve.  The propane at that temperature may not have sufficient pressure to make it through the gas regulator and valve which in turn is keeping you from having a lit pilot.

Barring that, you may check to see that your gas regulators at the tank/to the house are not freezing in the closed position which would have the same effect.

[cofee_iv]

Actually, I did check the furnace in the spring when it was not as cold as now, but just cool enough to get it to go on before the summer's heat set in. Nothing happened, so I doubt if anything is frozen.

Also, in the spring, the propane company came and replaced the tank (because we weren't using enough due to this problem). So, would that still be an issue?

Thank you for helping me work through this.

Oh, I saw that the inside of the panel door has reference to lights or something for diagnostics, but I don't understand how that all works or if even applies to me.

[dkpd1581]

The board will have one or two diagnostic lights that light or flash in a particular pattern.  That pattern can be interpreted by using the table printed on the door or on the board itself. 

Start with the error code and work from there. 

Can you manually get the pilot to light.  If not bleed the gas line, look at the thermocouple, the gas valve, the gas regulator - make sure it is not a 100% cut off.

If the pilot lights and goes out after a while, change the thermocouple, verify that the gas regulator is not a 100% shutoff regulator.  100% shut off valves do not bypass gas to keep the pilot lit and will starve it for gas within minutes.

[cofee_iv]

The only problem with the diagnostics is that I don't see the light that is supposed to be giving the signals. Can you describe where I would see that? Thanks a lot for your patience! I will check on those other issues.