Furnace Output Temperature
My electronic air filter just died and I substituted a replacement type air filter. Is there a normal average or rule of thumb to determine if output temperature is excessive on a gas-fired furnace? I know there are devices to prevent over heating but I just wondered if this filter was blocking airflow. The output is 150°F.
Answer:
Shouldn't matter. The filter is usually placed in the return plenum before the burners. So the air passing through the filter is just room temp, not the furnace temp. My electronic air filter just died and I substituted a replacement type air filter. Is there a normal average or rule of thumb to determine if output temperature is excessive on a gas-fired furnace? I know there are devices to prevent over heating but I just wondered if this filter was blocking airflow. Gosh, 150 is a bit hot. Even in a large home, that might make the hot air out of the register maybe above 135 degrees. If your furnace has a multi-speed fan, I would suspect a problem there. A fresh replacement filter not so much. Yes, I understand that air flow volume and speed will affect the amount of heat transferred from the fire box heat exchanger, and you suspect the speed and the air volume has been reduced by the air filter. I presume the furnace fire box has a upper temperature limit control, and it is working order. Just not kicking in. I also presume you have taken the temperature with, and without, the replacement filter in place. And the result is very little temperature difference with and without the filter. (10 minutes or so with a filter won't hurt.)