Requesting recommendations for replacement greenhouse heater

[Jeffy B]

Hello All,
It has been quite a while since I have been on OrchidTalk. I have a Monticello 8x16 greenhouse that has been operational for 3 years, My Johnson Controls thermostat went out on me several weeks ago and I lost over 25 orchids due to the heater being on for multiple hours. My electrician determined the Johnson thermostat needed to be replaced and the new one I purchased was installed last week. It appears my heater is also not working properly and my guess is the thermostat may be the issue. I live in the Atlanta area and the cold temperatures will not be a big concern within the next few weeks but I need to replace the heater ASAP. The heater's minimum temp is 50 and should come on but it is heating when it is well over 50 F. I have an exhaust fan wired to the Johnson thermostat which is integrated with the heater. Does anyone have recommendations (brand/model) for a 240V heater? Any assistance would be greatly appreciated.
Jeffy B

[raybark]

Jeffy,

An electric heater is likely just an on or off thing - if it heats, it is still working, so it sounds like the controller is the issue. Maybe I'm misreading your post, but the heat should come on when the temperature is too low and the exhaust fan should be on when it's too high, so how can that work off of one thermostat?

Might the addition of the fan be overloading the thermostat?

What heater do you have?