This weekend I realized my furnace fan was running non-stop. My first
thought was that we'd left the blower switch on, as we frequently do to keep
air circulating in the house. But the blower switch was off, and even
turning the HEAT/AC switch to OFF still left the blower running.

Is my thermostat finally toast? Is there a relay somewhere on the furnace
that controls the blower that might be stuck? Or is it the electronic
furnace control module? Or something else. How do I tell what is bad?

The thermostat is a programmable White 5/2 day 4 setting electronic.

The furnace is a Heil/Tempstar 100K BTU upright condensation furnace, about
15 years old. This fall the blower was replaced after it died.

NOTE: I would recommend everyone *** AVOID *** Heil Tempstar like the
plague. The stainless steel heat exchanger rusted out prematurely, about 3-5
years IIRC. It was repaired by a local service person, but he told me there
had been a safety recall on this unit. No notice was ever sent out in spite
of having "registered" the warranty. When I contacted the manufacturer, they
confirmed the recall, but wouldn't pay for the repairs. They had a "secret"
recall that had "expired" before mine finally failed. It seems they would
rather kill their unsuspecting customers than have to pay for warranty
repairs. There have been at least 2 other design defect failures that I've
ahd to eat since then. This is *** NOT *** a company you want to do business
with.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD"
To reply, remove the TRABoD!
Kaplow Klips & Baffle: http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf
www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org

People who exercise their embryonic freedom day after day,
little by little, expand that freedom. People who do not will
find that it withers until they are literally "being lived."
They are acting out scripts written by parents, associates, and
society. --Stephen R. Covey