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carrier furnace problems..still

6K views 23 replies 6 participants last post by  kevinp 
#1 ·
my carrier furnace isnn't working properly. the fan/blower runs constantly on low. the pilot light stays lit , but no flames on the burners.

i replaced the t-stat , the transformer and the fan control circuit board. nothing has changed anything.

needin' some help
thanks kevin
 
#3 ·
Sounds like you replaced everything but the the one part staring you right in the face.
If this is a true pilot like you say than it has three wires going to it. Green -white and yellow. This is a heat activated switch that first lights the pilot and after the pilot has sufficiently heated the metal warp switch built into it, the warp switch turns on the main burners. Try taking the handle of a a screw driver and tap the pilot valve body. If it does not activate the burners the pilot is most likely bad. Sometimes it's the valve itself..but not very often.
 
#5 · (Edited)
would a bad pilot keep the fan running low all the time regardless of the t-stat setting? ??? the metal warp switch is where the 3 wires are going ? i understand that that switch being bad could stop the gas from coming on , but how would it keep the fan running on low all the time?
 
#11 ·
You probaly have 2 or 3 limit switchs on your furnace. one might be up by the flue on top of the furnace, anthor in the blower compartment, anthor might be located in the middle of the lower part of the furnace (behind gas valve).also maybe on either side of the burner box. They might have manual red reset button on top. If you locate these limits bypass them one by one until you get to the one that is open causing fan to run, if you have a meter that would be even better. I've worked on carrier furnaces my whole career but I'm having a hard time picturing what your unit looks like. So I am just going by where most limits are located on carriers
 
#12 ·
ok i just found a reset switch for the vent safty shut off. got gas now but no fan. i bet that was all i had to do but i ended up changing the t-stat .fan control board and transformer..so how do i get my fan running at the same time ?
thanks !!!
 
#14 ·
ok now the fan comes on and when the burners light the fan stops. after a minute the fan comes on and runs. everything is cool but why does the fan run for a few seconds before the burners come on then stop when the burners light? after the burners warm up the blower comes on and all seems normal
 
#15 ·
Not really sure i have an answer for you on that one, unless you have an older model carrier that brings the fan on temp and not a time deley. If thats the case when your fan started the first time it cooled down the heat exchanger low enough to shut off the fan and once your furnace heated up enough your fan ran normally. Unless you have wired your new t-stat or circuit board wrong.
 
#16 ·
it might be a temp control like that, but i don't think so. when i finally got the burners to come on the fan came on and ran for a moment even though the furnace was cold. then the burners come on and the fan goes off. after about a minute the fan comes on again and all seems normal

thank you for your time and help on this , i greaatly appreciate it.
kevin
 
#21 ·
the damper safty switch. it tripped and the curcuit breaker tripped when my wife was playing with all the controls..just sliding them here and there cuz she had no idea how to work the thermastat. had never had a problem till then. i heard her rapidly sliding and turning all the switches every which way.

cleaned everything inside and oiled the motor. i even put the other fan control panel back in but the same thing. fan comes on. then the burners, and the fan stops. after a minute or two the fan comes on and it works ok.
 
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