I've not been to look at this yet (not my house or rental), but this
would be an older furnace in the crawl space. What we want to do is heat
the house up to about 120F by bypassing the thermostat. This heats up to
about 100 F and then the furnace cycles off. Is it common for an older
furnace to have some high limit cutoff? Since we are starting at 90+,
this didn't seem to be a stretch. The high limits that I know of I
wouldn't think would be set that low and wouldn't be in the air flow.
I'm a tall guy and I want to minimize the time I spend in the crawl
space, not that I want to do it at all!
For those of you that don't know, bedbugs and cockroaches expire at 113F.