This is the same as the limit switch, just a second one it is still a normally closed circuit that opens at whatever predetermined set point
When a typical residential furnace or gas package unit "high limit switch" is found to be bad it is replaced with a new one-not repaired.
Bad low limit switch,fan switch.
This is a switch designated to stop a peice of equipment before it does damage to itself or the surroundings.
Bad hi limit switch or filter stopped up
Check the error code on the control board at the furnace. It could be a number of things. If the furnace is not lighting, it could be the ignitor If the furnace lights then goes out right away, it could be the flame sensor If the furnace lights then goes out after several minutes, it is a limit switch. Turn the tstat fan switch to on and see if the fan comes on, if it does not you have no power to the furnace, check the breakers or cutoff switch.
Gas furnace have several safeties installed for your protection. If for some reason one of these safeties are not opening or closing the furnace will not fire. Most likely the pressure switch, high limit or transformer may be faulty. If it is an older model check the thermocouple.
No You can't cover the return air. Because the limit switch in the furnace will trip. If the furnace was working ok before I will check for air leaks in the return air. Good luck
Not likely, could be hi temp limit switch or bad air flow.
because round (mushroom furnaces) have limit in diameter of furnace, rectangular (Rachette furnace) can solve those problems
The question is why would you want to and which limit are you suggesting? Bypassing any limit would decrease the safety features designed to protect the equipment and occupancy. Limits and safety interlocks are sometimes bypassed for troubleshooting purposes or emergencies but I would not unless you have qualifications to determine the consequences.
The phone book.
If it`s a heat pump, they do that, heat is not instantaneous with them. If it`s a furnace the fan/limit switch or fan delay timer whichever you have, needs to be adjusted.