Excitement in the greenhouse! I stepped inside my glass-to-ground lean-to greenhouse and it was hot! Intake fan not running, vent louvers not open. Went to check the thermostat for the system, which has a small cover over the top of the coil to protect it from the sun. And an agitated wasp flew out. My quick glimpse showed me a couple more crawling over a nest. Yikes! Back away. Discuss with Mr Jam Lord. Flip switch inside greenhouse to off. Get the can of wasp and hornet spray, edge into the greenhouse - and a wasp lands on the can. Reflexively slap the lid over the top, thus trapping wasp. Now what? Exit to driveway. Shake can repeatedly, hoping to dizzy the wasp, then squash it. Remove cover and it flew off. Sigh. Into greenhouse, tap spray nest, stunning both wasps which I squashed. Remove cover. Back outside to driveway. Shake nest loose and step all over that. Back into greenhouse and see there is a mud dauber wasp nest attached to coil, filling all the space to wall. Break that loose, remove dust, turn switch to on. Nothing happens. Lights in greenhouse do not turn on either. Trudge over to circuit breaker box. Figure out which circuit is for greenhouse. Reset. Eureka! Fans run, louvers open. And now I don't even remember why I went in there to begin with. But I'm sure glad I did. Also glad there are two roof vents that operate on expansion of wax cylinder. Imagine how hot it could have gotten without them.