Gas and Oil Home Heating Furnaces - need new blower moter

was able to determine that a new fan moter is needed .need info on how to remove old moter , can gain acess to moter but cannot figure how to get it out .the unit is a thompson very old model #511-G6-105 .serial#A.....moter#317-73.any help,would help

Remove the blower housing and motor from the cabinet as an assembly. Look for screws holding it in place. Disconnect the wiring etc. (Don't forget to turn the POWER OFF.)

Once the assembly is out of the cabinet, the rest of the process should be simple enough.

many,many thanks on your instructions on how to remove and install new fan moter..it was a breeze .(pun intented).runs great ,but now the fan will not shut off unless main switch on the unit is turned off.stat is new .....wireing on new moter is as follows. red 2red,yellow 2black,white 2white blue capped off.question,should the blue be connected to one of the others?will wait for your answer.THANKS DAVIDLC ......(note) the red,black,white and blue wires are comming from the new moter

sounds like the high voltage side of the motor is wired correctly, but that a control switch is closed. DO NOT HOOK UP THE BLUE WIRE!! this could energize the motor in 2 speeds at one time which will burn it up so quick you will not believe....immediately. start by disconnecting the wire going to the "g" terminal at the tstat. if the fan stops, problem is tstat. if continues to run, could be fan relay, or if carrier mid 80's , and some other models, the transformer. do you have a meter?

Thanks hvac-4u for your reply...as you instructed I disconnected the "G" WIRE FROM THE TSTAT AND THE FAN CONTINUES to run .The relay is new. I noticed a "nick " or burn mark on the tranformer where it might have touched the metal inside the unit ,could this have shorted out the tranformer? I have no meter.

1) Disconnect the green wire at the relay. Does it continue to run? (If no, the stat cable is defective...shorted rom Red to green.)
2) If yes, tap on the relay gently with the handle of a screwdriver. The contacts may be tack welded togerther or the iron magnetized.
3) The transformer is working. (It provides the 24 volt control power.)
4) Take the power wire that goes to the fan from the relay contacts off of the relay. If it continues to run, the power is getting there by another path on another wire.

Thanks Lynn for your reply ....Is there another wire that is replacing the green ? because I have no green wires coming from the relay.the color wires coming from the relay is as follows. thick red,thick yellow, black. thin yellow thin red....the unit is a thompson,at least 40 years old

Does the fan speed change when you turn the fan ON at the stat? With 5 wires, your relay probably supports a 2nd path to the fan motor. This is common on gas heat and AC. The heater runs on low speed and the AC runs on a higher speed.)

The thin wires are probably the 24v control wires (one of which is the green wire.) Disconnecting either of them would de-energize the fan relay. If the fan continues to run, tap the relay and go to the next paragraph if it still continues to run.

The three power wires are connected to the relay contacts. One terminal is Common, one is N.C. (normally closed...when the relay coil is not powered up.) and the 3rd is N.O. (normally open...when the relay coil is not powered up.) If they are marked in the plastic of the relay, disconnect the N.O. wire and see if that restores normal operation on cooling. (The wire will need to be replaced and the underlying problem dealt with before the heating season. This would at least narrow down the problem to the heating circuit.