| i think ur asking what is high speed on heater?, it is used when you use your air conditioner, "if equipped", it makes the blower run at higher speed to move more air more efficiently,lower or medium speed is for the heat cycle of furnace, to help heater heat the supply air going thru vents, and the normal suction refers to the inducer motor tubes, if it is restricted due to faulty switch, or debris in these valves, u probly need an expeirienced repair person to test these valves,. hope this helped |
