Hello , I have a nordyne ra 80+ upflow/horizontial furnace. Currently my furnace is on but does not give off any heat, rather I see no flames on my furnace. My LED display states there is a fault condition of "Limit circuit open or External load on W" What does that mean. Can anyone shed some light on this matter, I really need some help. Bye for now :(

The limit controal is open caused by high temperatuure.

Check your air filter, a dirty air filter can cause it to over heat and kick off the high limit. Also check your duct work make sure there are no restrictions for air flow, no kinks or drooping, also make sure there is nothing in front of the return grill inside the house that would block air flow.

Thanks for the suggestion, this happened when I closed all the vents because work was being done on the house. I had some contractors sanding the floor and I did not want the dust getting into the vent. I will make sure to open the vents clean the filter, vacuum the furnace. My other question the furnace does not ignite how do I get it to ignite.

After your sure there are no more restrictions to airflow and a clean filter then try cutting power from furnace completely off (t-stat to off) for about 2-5 miniutes then back on this will reset the board. Some limits have a reset button on the limit that you can reset by just pushing the small button. The limit should be located just above the burner assembly. Also try cutting power to furnace completely You may want to send an e-mail to T-Top he is a veteran in the field. I have only been in the field for a couple of years so I am not sure about the reset on the High limit. Some units automatically reset the limit after the furnace cools down. If this does not solve the problem then the limit may have to be replaced.