Sunday, October 4, 2009
Gremlins Came A Calling
Woke up the other morning noticing that it was rather warm and the furnace was still running. Got up to look at the digital thermostat and saw that it was set for 98 degrees!! It was up to about 74 degrees inside so I reset it to 68 degrees and made myself a cup of coffee and set about the business of waking up, which means I'm sitting in my recliner with my eyes closed, rousing from time to time to have a sip of coffee, hopefully before it gets too cold. As I'm sitting there, contemplating life, I notice the electric tea kettle sits on the counter right next to the thermostat. I'm thinking the steam it gives off must have gotten into the thermostat and the moisture must have shorted out the electronics. I also noticed that the furnace had been running for a while again so I got up to have a look and see that the set temperature has crept up to 76 degrees. I reset the temperature to 68 and watched it creep up to 76 again. Definately something going on. A close eyeball inspection doesn't reveal anything obviously wrong and an email to the manufacturer echoes my thoughts of 'try resetting it and if that doesn't work it must be defective". Off I go to the big box hardware store and pick out a new thermostat. Our trailer has a gas furnace and a roof-top A/C with an optional "heat pump" feature which is a heat strip so I need a thermostat that can handle the extra functions plus, as long as I'm getting a new one, one that is programable. My only choice was one made by Honeywell, an RTH 7500. Following the instructions I begin the simple task of replacing the thermostat. Wait. Did I say simple? The instructions have you mark the old wires so you can match them to the new thermostat. Ok, got that, but wait, the colors and markings don't coincide with the new thermostat's. For example, the new thermostat has a connection for a blue or orange wire (don't have an orange one) that controls the change-over valve for either heat or cool. My blue wire is the common or -12 vdc and I don't have a change over valve either. To make this long story shorter, after several hours on the internet I gleaned enough information to make the connections needed to get the furnace running again. I think I have the wires connected to the right terminals now but because we are currently camped in our daughter's driveway and I can't run the A/C on the 15amp circuit we are on I haven't been able to try out the other functions. That will have to wait until we are camped somewhere with at least a 30 amp hook-up. I'm just glad we have heat for now since the temperature at night is in the low 50's to high 40's.