My gas furnace that came with the Mobile Home I just purchased will not ignite the Pilot Lite. All valves from tank open, followed instructions. No Spark

Bad or dirty thermocouple

Could be a multitude of causes. Here are a few common ones.

Igniter electrode dirty or corroded.
Igniter misaligned.
Failed circuit board.
No power to furnace.
Time delay switch defective.
Sail switch defective.
Overheat switch open/defective.
LP gas valve not opening. Check electrical connections before replacing valve.
Failed to purge system after storage. Light the stove and let it burn for a minute.
Manual LP valve (close to furnace) not opened.
Valve on main LP tank not open.
LP tank empty.

I don't know what kind of furnace you have. But most furnaces have some sort of pilot first than after it is proven than the main gas will come on. Either a standing Pilot with a thermocouple. A hot surface ignition or Spark ignition with a flame sensor. Or a direct fire system where hot surface or spark ignitor start first than all the burners send a 1 sec blast of gas which is proven by the flame sensor if it proves the gas valve stays on.....
In what you have said you have 24 volts to the gas valve and it has not lite. then does the gas valve have a pilot tube???Does it have a thermocouple?? Do you smell gas?? If you don't smell gas then the main part of the valve has not opened. The Pilot valve has to open first and prove before the main gas will come on. I hope this helps. If you still need help repost with the name and model # of the furnace.

1) Open following link to identify type of gas control and read printed 'how-to-light-water-heater' instructions for each different gas control valve:
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent

2) Same printed instructions should appear on side of tank by gas control valve, and inside product manual.

3) Add a comment March 2013 and describe gas control valve.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Hello
Sounds like the thermocouple is going bad.The thermocouple is a thin tube that runs from the pilot lite to the gas valve.
What it does is it sences the heat from the pilot lite and keeps the gas valve open to allow the pilot to stay on.
This can be easily repaird by shutting off power and gas to your heater and removeing the thermocouple from the gas valve,then unclip or unscrew it from the pilot lite area.
Any plumbing supply store or home depot or lowes should have these.

Once you get a new one,install to gas valve and pilot lite area then turn on power and gas to heater and follow pilot lighting procedure,you may need to hold gas on for 60 seconds.

Here is a picture of the thermocouple so you know what to look for.


http://thermocatalytic.com/Thermocouple.JPG
http://homerepairgeek.com/wp-content/uploads/2010/12/furnace-thermocouple.jpg

I have experience with coleman furnaces installed in mobile homes. There is a red switch on the gas valve. Some models require you to slide the red switch to the top and hold. Holding is allowing gas to the pilot. You have to stick a long match,grill igniter, to stick through the inspection hole (a little flap or door to see inside the burner area) and hold the match over the pilot while holding the switch upwards at the same time. Others have a pilot selection on the gas valve which you slide the red switch to pilot and push down and hold while liting the pilot. You may need help with holding the door open while doing this. If you can you can use the copper line for the thermocouple to hold the door open for you. Good luck

Change the ignition time relay.

Hi, normally when you turn the gas off at the flex line valve and leave it off for awhile, the gas has to clear the gas valve and lines up to the pilot. Purge its self of air before it will light again. It will take the electronic ignition several clicks and more before there is enough gas to light the pilot and then open the main gas valve to fire the burners. Tell me, what kind of gas furnace is this when you speak of water? you say the site glass was full and you had to drain it and then the ignitor kept on clicking when it normally only took one click to light it. Please let me know the style as in a split system, a package unit, all in one, or what you have. I will wait to hear back from you. If the pilot does not light right away, then yes let it continue to click and see if it will light. On a heater with the electronic ignition control module on it or a circuit board, this is what tells the pilot coil to energize to light the pilot. It will send power to the pilot coil to open and let gas through to light and same for the main gas valve, will get a signal to open when the pilot is on. It will not open unless the pilot is lite for saftey. I will wait for you're responce.
Shastalaker7

if it has a pilot, you can follow the pilot tube from the gas valve back to the burner assembly and find it. It may not have one and if this is the case, the air flow switch is supposed to close when the inducer fan comes on . If the flue is clogged, condensation in the bottom of inducer fan(would hear cracking). then after the draft safety switch is closed,the gas vavle will get 24 volts and allow the gas valve to open

Honeywell makes an electronic ignition conversion kit. (White rodgers also has one but it uses a mercury switch which can be expense if it goes bad). A good service man can install the "Honeywell Y86 Universal Intermittent Pilot Retrofit Kit". This is a "complete" kit for converting a standing pilot system to electronic ignition. It includes a new gas valve, ignition cables with connectors. ignition module and a pilot assembly. It does not include pilot tubing (pilot tubing is cheap). This kit also comes equipped for either natural gas or propane. Your heating guys probably don't know about it because they are to young and not familiar with the old days. Or they just don't care and would rather sell you a furnace. I think that they just don't care. I live in Ohio I just opened up the "new" Johnstone Supply catalog. This part is "not" outdated its on page 450. Do not let these heating guys buffalo you into a new furnace. You are to smart for that! If you weren't you would have believed them and bought something you don't need. Instead of researching on the internet.
The bad news is this kit lists for $456. plus labor.
Good luck!