Garn Flue Temp Shutting Down Prematurely

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New Member
Mar 2, 2023
Belmont, Maine
Hello folks,

I have a Garn 2000 heater that heats a radiant slab in a horticultural greenhouse. The unit is 12 years old, but ive only owned it for 2. Recently the flew temperature sensor has been shutting the unit down prematurely. I have witnessed it shutting down as high as 309° down to 200. It does not happen all the time and seems totally random. I have pulled it out and cleaned it and checked wiring. Also, the tank temp sensor has Started going haywire and will only read either 320 or 32 degrees. Both sensors were replaced by me when i installed the unit in 2021. The next question; has anyone had experience with Garn controller mother boards failing? Tempted to replace the board but trying to save $400+ dollars if i can.

hedge wood

Feeling the Heat
Mar 1, 2009
Eastern NE
BelmontBahn Welcome to the forum. Can't help with the controller. My Garn 2000 still has the timer to control the blower. Hopefully you will have better luck with the workmanship on the welds then I have on mine. I thought about installing the system you have but just don't see there being enough of wood saving to off set the cost of the system and the cost of the repairs as you are finding out. You could always convert yours to a timer and regular gauges.
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