had draft motor replaced

harley75 · 01-21-2009, 10:26 AM

Had the draft motor replace fasco AO90 the old motor was a AO smith 673 now the furnace fire up run for 3sec shut down for 5seconds and fire again didn't do that before.Before it ran for 4min then shut down then all over again

kennzz05 · 01-21-2009, 11:01 AM

if you paid someone to repair it than id be calling them back, as they may have replaced something that wasnt the problem. typically a bad draft motor is just that bad... as in it dosent run at all. if it ran for several min and than it quit than perhaps it was in fact bad, but it could be other causes that shut the motor off in the first place .really dont have enough background info to speculate

harley75 · 01-21-2009, 11:08 AM

Quote:

Originally Posted by kennzz05

if you paid someone to repair it than id be calling them back, as they may have replaced something that wasnt the problem. typically a bad draft motor is just that bad... as in it dosent run at all. if it ran for several min and than it quit than perhaps it was in fact bad, but it could be other causes that shut the motor off in the first place .really dont have enough background info to speculate

the bearings were bad in the old one it screamed and locked up but it never ran like that before 3 sec fire up the flame out for 5 sec the fire up again i have a digital tstat but i removed the battery's and put back in

kennzz05 · 01-21-2009, 11:37 AM

flame sensor may need cleaning, try searching for that info here. you could try reading out the pressure switch with a meter when it quits. on voltage setting you will have no reading when the switch is closed(running)and it should be closed continuesly while draft motor is running and 24v when it is open is the unit displaying any codes on the circuit board?

harley75 · 01-21-2009, 11:54 AM

Quote:

Originally Posted by kennzz05

flame sensor may need cleaning, try searching for that info here. you could try reading out the pressure switch with a meter when it quits. on voltage setting you will have no reading when the switch is closed(running)and it should be closed continuesly while draft motor is running and 24v when it is open is the unit displaying any codes on the circuit board?

what i'm thinking they told me the fasco ao90 is 90cfm now the ao smith that was on it #673 is 100cfm would that cause this.

gene_champ · 01-21-2009, 12:01 PM

i had a tiny crack in the vac. hose that went to the vac. sensor. it acted like that, as i recall. hth

harley75 · 01-21-2009, 12:04 PM

Quote:

Originally Posted by gene_champ

i had a tiny crack in the vac. hose that went to the vac. sensor. it acted like that, as i recall. hth

new hose if thats hte case then it could be the motor that is 10cfm short

gene_champ · 01-21-2009, 12:15 PM

bypass vac. microswitch (short the switch). that will tell if switch is bad, or is getting enough vac. cfm's to work.

this is for testing only. don't operate this way.

harley75 · 01-21-2009, 01:28 PM

Quote:

Originally Posted by gene_champ

bypass vac. microswitch (short the switch). that will tell if switch is bad, or is getting enough vac. cfm's to work.

this is for testing only. don't operate this way.

thats what it was not enough vaccum now to find a ao smith 673

gene_champ · 01-21-2009, 04:09 PM

if you not in a great hurry. i don't know anything about them, but i am looking at them now to buy a hrv.
http://www.climatedoctors.com/

harley75 · 01-21-2009, 04:21 PM

Quote:

Originally Posted by gene_champ

if you not in a great hurry. i don't know anything about them, but i am looking at them now to buy a hrv.
http://www.climatedoctors.com/

nobody has them till late feb.Backordered my question the motors don't come with the fiberglass backing where can i get it i found a motor same one the only place that had it.Also for those people that say the fasco ao90 is a replacement for the ao smith 673 there wrong the ao90 is 90cfm and the 673 is 100cfm i guess it depends on the system to

01-21-2009, 10:26 AM	#1
harley75 Member Join Date: Jan 2009 Posts: 34	had draft motor replaced Had the draft motor replace fasco AO90 the old motor was a AO smith 673 now the furnace fire up run for 3sec shut down for 5seconds and fire again didn't do that before.Before it ran for 4min then shut down then all over again Last edited by harley75; 01-21-2009 at 10:27 AM. Reason: add

01-21-2009, 11:01 AM	#2
kennzz05 Member Join Date: Nov 2008 Location: palm coast fl Posts: 551	had draft motor replaced if you paid someone to repair it than id be calling them back, as they may have replaced something that wasnt the problem. typically a bad draft motor is just that bad... as in it dosent run at all. if it ran for several min and than it quit than perhaps it was in fact bad, but it could be other causes that shut the motor off in the first place .really dont have enough background info to speculate

01-21-2009, 11:37 AM	#4
kennzz05 Member Join Date: Nov 2008 Location: palm coast fl Posts: 551	had draft motor replaced flame sensor may need cleaning, try searching for that info here. you could try reading out the pressure switch with a meter when it quits. on voltage setting you will have no reading when the switch is closed(running)and it should be closed continuesly while draft motor is running and 24v when it is open is the unit displaying any codes on the circuit board? Last edited by kennzz05; 01-21-2009 at 11:40 AM.

01-21-2009, 12:15 PM	#8
gene_champ Newbie Join Date: Jan 2009 Posts: 19	had draft motor replaced bypass vac. microswitch (short the switch). that will tell if switch is bad, or is getting enough vac. cfm's to work. this is for testing only. don't operate this way.

01-21-2009, 04:09 PM	#10
gene_champ Newbie Join Date: Jan 2009 Posts: 19	had draft motor replaced if you not in a great hurry. i don't know anything about them, but i am looking at them now to buy a hrv. http://www.climatedoctors.com/

had draft motor replaced