limit circuit open

[bridgeman]

I have Gibson furnace, fan blows but no heat. code light say limit circuit open or load on w.

I don't know what it means, thanks for help.

[mr horsepower]

if you were provided with that information, what are you intending to do with it? (rules prohibit giving out info. that is going to be used for d.i.y. purposes) that being said, a generic answer regarding limit switches is they do just that - they limit. a thermal limit, for example, will open a circut when a temp. limit is achieved (explaining open vs. closed circut - a light switch that is off is an open circut, when on is a closed circut). SOME limits are only resetable manually. i'm not opposed to an homeowner knowing how to do this provided they're aware that if it needs to be reset anymore than once, its time to call someone with a deeper understanding of what is causing the problem. that means the limit itself is rarely the problem. its purpose, in the case of a manually resetable one, is to give an alert to a problem that exist elsewhere in the furnace which caused its temperature limit to be reached and to not allow further furnace useage til the problem is investigated.

[beenthere]

Have you changed the air filter recently.

Is this a new furnace.