Once the vent is moved through the pressure switch the system comes on and starts heating.
Furnace draft inducer blower noise.
Also what are you noticing.
Do you hear the motor whining or some other problem.
A draft inducer or vent blower is the most common problem on a gas furnace or boiler to cause a noticeable noise.
You can fuse the furnace model number to shop around for the inducer motor assembly and probably buy it for 200 250 or so.
A furnace inducer motor noise can be one of the main problems home owners experience with this component which is mostly found in newer high efficiency furnaces.
The first day the noise was intermittent but by day 2 3 it was constant.
Usually the inducer motor assembly can be removed and replaced in a half hour or so.
It s the first sequence of events upon a call for heat and it runs through most of the heating cycle.