Post by papaof2 on Apr 20, 2022 17:00:17 GMT -6
The gas-fired furnace has been doing some odd things in recent months -
- You hear the induction blower start, but the igniter doesn't get hot.
- You hear the induction blower start, the igniter heats but the gas valve doesn't operate.
- You hear the induction blower start, the igniter heats, the gas valve operates and the burners light but it all shuts off before the "hot enough" sensor starts the blower.
- You hear the induction blower start, the igniter heats, the gas valve operates, the burners light and the "hot enough" sensor starts the blower.
This is a regular pattern and I've tried to catch it happening on video to be able to show the HVAC guy when he's here for the seasonal (heating/cooling) checks but I never have the phone in hand when it happens.
Today I was reading in the room where the thermostat is located (thermostat is about 6 years old). I heard the "click" of the thermostat's relay and then the click as that relay released a few seconds later. I walked over to the thermostat and watched the display. The desired temperature is 68F. The display changed from 68 to 67.5, the relay clicked as it operated and a few seconds later the display changed back to 68 and the relay clicked as it released. The thermostat did that several times. I pushed the thermostat up one degree to 69F and it ran long enough to warm the space that one degree and settled down - no more "click on", wait a few seconds and "click off".
I think I may have solved the "furnace" problem. The thermostat (3M-22) that cost me about $30 six years ago is now $100 new in the "Filtrete 3M" wrappings. I found another of the original on eBay - NOS - for under $40 delivered. Next week we'll see if my detective work was accurate. The other choice for the problem is the furnace controller board - $800 or so if the HVAC guy replaces it, about $200 if I replace it. Want to guess what my next action will be if the new thermostat doesn't resolve the problem?
- You hear the induction blower start, but the igniter doesn't get hot.
- You hear the induction blower start, the igniter heats but the gas valve doesn't operate.
- You hear the induction blower start, the igniter heats, the gas valve operates and the burners light but it all shuts off before the "hot enough" sensor starts the blower.
- You hear the induction blower start, the igniter heats, the gas valve operates, the burners light and the "hot enough" sensor starts the blower.
This is a regular pattern and I've tried to catch it happening on video to be able to show the HVAC guy when he's here for the seasonal (heating/cooling) checks but I never have the phone in hand when it happens.
Today I was reading in the room where the thermostat is located (thermostat is about 6 years old). I heard the "click" of the thermostat's relay and then the click as that relay released a few seconds later. I walked over to the thermostat and watched the display. The desired temperature is 68F. The display changed from 68 to 67.5, the relay clicked as it operated and a few seconds later the display changed back to 68 and the relay clicked as it released. The thermostat did that several times. I pushed the thermostat up one degree to 69F and it ran long enough to warm the space that one degree and settled down - no more "click on", wait a few seconds and "click off".
I think I may have solved the "furnace" problem. The thermostat (3M-22) that cost me about $30 six years ago is now $100 new in the "Filtrete 3M" wrappings. I found another of the original on eBay - NOS - for under $40 delivered. Next week we'll see if my detective work was accurate. The other choice for the problem is the furnace controller board - $800 or so if the HVAC guy replaces it, about $200 if I replace it. Want to guess what my next action will be if the new thermostat doesn't resolve the problem?