I love my new Fireview and I have enjoyed learning how to burn it properly. I recently added a combustor probe thermometer and I also use an IR gun to check the flue surface temperature about 18 inches above my stove.
In email inquiries with Woodstock Soapstone I learned it is not necessary to wait 45 minutes or so for the stove-top thermometer to reach 250 F. My new routine is to get my flue surface temp up to 350 to 375 F, which takes less than 10 minutes, let it burn about 10 more minutes to fully heat the combustor, and then raise the bypass lever. Since the flue surface temp is about half the internal flue temp, a surface temp of 325 F or more indicates the temp inside the flue is well-above the 500 F temp needed to ignite the combustor.
Watching the combustor probe temp I see that the temp behind the combustor is about 500 - 550 F just before I raise the bypass lever. After the combustor is ignited the probe temp rises to around 900 F. I note the stove-top temp rises to about 450 F, so the stove-top thermometer is a good 50 percent proxy for the temp behind the combustor.
As others have noted, once the combustor is ignited the flue surface temp drops significantly and may even drop below the 250 F level which is ordinarily needed to prevent creosote formation. However, the combustor burns flue gas components that might otherwise form creosote, so I understand it is OK for the flue surface temp to drop below 250 F if the combustor is operating.
In email inquiries with Woodstock Soapstone I learned it is not necessary to wait 45 minutes or so for the stove-top thermometer to reach 250 F. My new routine is to get my flue surface temp up to 350 to 375 F, which takes less than 10 minutes, let it burn about 10 more minutes to fully heat the combustor, and then raise the bypass lever. Since the flue surface temp is about half the internal flue temp, a surface temp of 325 F or more indicates the temp inside the flue is well-above the 500 F temp needed to ignite the combustor.
Watching the combustor probe temp I see that the temp behind the combustor is about 500 - 550 F just before I raise the bypass lever. After the combustor is ignited the probe temp rises to around 900 F. I note the stove-top temp rises to about 450 F, so the stove-top thermometer is a good 50 percent proxy for the temp behind the combustor.
As others have noted, once the combustor is ignited the flue surface temp drops significantly and may even drop below the 250 F level which is ordinarily needed to prevent creosote formation. However, the combustor burns flue gas components that might otherwise form creosote, so I understand it is OK for the flue surface temp to drop below 250 F if the combustor is operating.