There have been many, many questions about how to control temperature from a heater since I joined this site. During the last cold snap, I needed a very quick way to control the temperature from my 60K BTU shop heater. Without control, the heater quickly makes the interior temperature way too high. There were no controllers locally available, so I rapidly made one from parts I could get locally and some from my "stock." I've used it for about a week, and found it performs flawlessly. This is not a super-cheap solution, just a quick and effective one. The main components are; one Honeywell electronic thermostat, PN RTH23-B for about 35 bucks at Home Depot, and a 10-amp rated relay Omron LY2, available from Radio Shack for about 6 bucks. I also bought the relay socket to allow a quick change in the event of a relay failure.
The big advantages of the Honeywell thermostat are programmability, and nice LCD readouts of temperatures, settings and even the current time. It uses no mercury tilt switches, so can be used in any position. You can save up to four different profiles for two separate time intervals (weekday/weekend) for energy savings. A manual override is also available for instant temperature setting. The output only drives 1A @24 volts, so a relay or other driver is requires for most applications. The attached drawing shows how I connected a small relay to drive my shop heater.
Aside from heating my shop, I have an occasional need to control the temperature for some "glue up" projects. I plan on using the controller for these requirements along with small insulated enclosures for the items, usually just a few blankets hung over a simple frame. I'll need to beef up the output relay so I can run a small electrical resistance heater.
The big advantages of the Honeywell thermostat are programmability, and nice LCD readouts of temperatures, settings and even the current time. It uses no mercury tilt switches, so can be used in any position. You can save up to four different profiles for two separate time intervals (weekday/weekend) for energy savings. A manual override is also available for instant temperature setting. The output only drives 1A @24 volts, so a relay or other driver is requires for most applications. The attached drawing shows how I connected a small relay to drive my shop heater.
Aside from heating my shop, I have an occasional need to control the temperature for some "glue up" projects. I plan on using the controller for these requirements along with small insulated enclosures for the items, usually just a few blankets hung over a simple frame. I'll need to beef up the output relay so I can run a small electrical resistance heater.
