When I turn the power on to the furnace, it starts up as it normally would.

However, after about 5 minutes, the gas shuts down. The blower continues until it hits the cool down range. The gas does not shut down because of a temperature over-ride. It just shuts off.

When I power off the system and then power it on again, the scenario repeats itself. I have temporarily removed the filter to ensure air flow is at a maximum.

The board shows a continues green blink, signaling normal operations. I have been told it may be a bad limit.

Anyone care to comment or have a suggestion? Are limit swithces easy to replace? I have already replaced the blower myself when it died, and the gas valve when it also died. Yes, the system is old, but pretty soon, I'll have the Johnny Cash Cadillac of Furnaces...

Thanks in advnace...

A.G.

When I turn the power on to the furnace, it starts up as it normally would.

However, after about 5 minutes, the gas shuts down. The blower continues until it hits the cool down range. The gas does not shut down because of a temperature over-ride. It just shuts off.

When I power off the system and then power it on again, the scenario repeats itself. I have temporarily removed the filter to ensure air flow is at a maximum.

The board shows a continues green blink, signaling normal operations. I have been told it may be a bad limit.

Anyone care to comment or have a suggestion? Are limit swithces easy to replace? I have already replaced the blower myself when it died, and the gas valve when it also died. Yes, the system is old, but pretty soon, I'll have the Johnny Cash Cadillac of Furnaces.....

Thanks in advnace....

A.G.
And, it is a Rheam furnace, gas, in the basement, and probably 20 years old. I've seen some similar questions, but nothing with an answer specific enough to help...

Why would it be a limit switch problem if the temperature does not get high enough to trigger? Do they get old and stay open at lower temperatures when broken? Why would a power down reset it?

Thanks again...

A.G.