I have a Modine 150,000 BTU propane heater in my greenhouse, brand new installed 2 weeks ago, and today it is not starting. Checked the thermostat, wiring to power source and all checks out, but I'm not getting anything--no burners, no click of ignition. Any thoughts or things to check? Thanks!

If you had it professionally installed, call the installing company. If you installed it yourself, take out the install manual, & start from scratch. If all seems well there, get out the voltmeter & start tracing to see where power is being lost.