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
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
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.
form_title= Furnace Repair form_header= Keep the temperature comfortable when you repair your furnace. How old is your furnace?*= _ [50] Has the furnace ever been repaired?*= () Yes () No Please describe the problem in detail.*= _ [50]
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
Looking in your local Yellow Pages will provide a list of furnace repair companies. You do not need to take the furnace to them, they will come to your home and do an assessment of the damage and give you an estimate of how much it will cost to repair. When calling for repair estimates, make sure that the do not charge for the estimate and only charge for repair work done.
The best place to find information on repair parts for your furnace, is to check the site, of the compnay which you own the furnace from. This will lead you to the right place to purchase replacement parts.
Not likely, could be hi temp limit switch or bad air flow.
Turn the thermometer switch to offTurn the electrical service switch by the furnace to offTurn off the main breakerAfter turning off the main breaker disconnect the power line to the furnace