Farm thinking

Tomatoes in the greehouse

Sometimes we don't talk enough about the less fun aspects of farm living. So here is a good story.

Last night, as is my habit, I went out to check the greenhouses before I went to bed. We have alarms in the greenhouses that make a phone ring in the house if the temperature gets out of range, but I always go out and check in person, just to make sure. Last night it was about 20 degrees out at 10:30pm.

The first greenhouse was fine.

However, the second greenhouse seemed too warm when I opened the door. Sure enough, the thermostat said it was 74, which is not hot enough to trigger the alarm, but a lot warmer than the 58 degrees that we set the furnace to at night. So something was wrong. Our furnaces will heat the greenhouses to about 54 degrees above ambient, so if it was 74 in the greenhouse, and 20 outside, I knew the problem was that the furnace was going full bore, and for some reason it wasn't shutting off when it got to the set temp of 58.

But that is as far as I got troubleshooting it on my own. So I was faced with my first farm thinking problem. The non-farmer in me was tempted to say, "Well, I don't know anything about furnace repair, and furnaces seem kind of big and hot and scary, so I can't do anything here, except maybe watch the furnace overheat to the point of malfunction while burning of a zillion gallons of oil." But given that there were $10,000 worth of tomato plants in the greenhouse, and it was cold outside, that didn't seem like a good plan. So the developing farmer in me said, "Well, I guess I need to learn about furnace repair, right now, and I need to figure out how to fix this thing quickly."

The second thing farming has taught me is that even if you don't know how to do something, if you physically stare at the problem long enough, ideas will come to you. If I was sitting at the kitchen table thinking, "How do you fix a furnace that won't shut off?", I wouldn't have any ideas. But staring at the furnace set up in the greenhouse in the middle of the night, ideas started to come. Eventually I decided that either the thermostat switch wasn't working, or there was some kind of cross or short in the wire that ran from the furnace to the thermostat, and this cross was keeping the circuit open when the thermostat switch was trying to shut it. However, the thermostat switch actually showed it was shutting off at 58 degrees, and there were no obvious defects in the thermostat line.

Not knowing what else to do, I went to the shop and stared at the work bench for a while, flipping through the furnace manual at the same time. For some reason I saw a coil of thermostat wire under the layers of workbench debris. I didn't know it was there. "What if I replace the line going from the furnace to the thermostat? Either that will fix the problem, or tell me that the problem really is the thermostat switch." The second thought that came was, "Hmmmm, I hope this left over coil is long enough. . . ." The third thought was, "Hmmmm, I wonder how you replace the thermostat line on a furnace . . . "

Back to the greenhouse. What to do first? A good starting point seemed to be to shut off all the electrical current to the furnace system. As a non-electrician, I was glad that step occurred to me. The next step seemed to be to memorize how the original wire was set up, and do exactly that, with the new piece of wire.

A while later, the line was replaced, the power back on, and the furnace was shutting down at 58 degrees. Yay!

So what are the lessons here? (1) Don't rely on the greenhouse alarms, (2) when something goes wrong, stare at the problem until a solution presents itself, and (3) even if it is not obvious what to do at the outset, just keep moving forward, and assume you can figure something out as you go.

Now I need to go check the furnaces . . . goodnight!