Carrier BDP Furnace, No heat

[Scottthewolf]

Sorry, no model # due to it being worn off the furnace.  During the summer the air conditioner evaporator leaks condensate water on the fan control board and damages it.   Customer waited until the heating season to call me to tell me the blower fan runs 24/7 with no heat.  I replaced the fan control yet again telling the customer this is the last time I will do this, since she doesn't have money to replace the evaporator coil.

 

Now after replacing the fan control board, wiring the new one exactly like the old one, I get the ignitor lighting the pilot trying to constantly light the furnace burner with no attempts of the draft inducer or the blower motor coming on.  I checked the fan limit, it checks out good with continuity, I checked the draft inducer motor and it ohmed out good, and I checked the pressure switch on the draft inducer housing for continuity.  It all checked out good.  I also checked the resettable limit thermostat on the top of the furnace housing and that too checks out good with continuity.  The furnace blower motor now only works if you set the wall thermostat to run the fan on the "on" setting but it will not run if you set the wall thermostat on the "auto" setting.  What could be wrong???

[Cactus Bob]

you checked the pressure switch ? with an ohm meter ?

 

did you remove the lines and install a long one to one of the ports and suck or blow into it to see if the contacts open and close ?

[Scottthewolf]

yes, checked both of the above.

[Cactus Bob]

is the new board the programable type , with dip switches to use with multi oem boards ?

 

did the new board have an adapter harness , to adapt it to your furnance ?

 

i would guess you got a single wire in the wrong spot somehow

 

or you just have a bad new board

Edited October 27, 2013 by Cactus Bob

[Scottthewolf]

It's an exact replacement, no adapter harness and non programable.

[RegUS_PatOff]

... Sorry, no model # due to it being worn off the furnace.

hmmm ...

maybe post part number of Fan Control Board

(and any other Boards)

 

[Scottthewolf]

Fan control board Robertshaw 695-101, which is an exact replacement for Carrier HH84AA021.

[RegUS_PatOff]

some info:

 

Igniter Glows Red but Main Burner Will Not Light
Possible Causes:
Improper Igniter or Sensor Alignment
Faulty Ignition Control
Faulty Gas Valve
High Inlet Gas Pressures
Polarity Reversed
No Earth Ground

 

[jb8103]

If the pressure switch is not proving, the furnace should not attempt to ignite. Without the draft inducer the pressure switch cannot be proving. Something else has gum in it.

 

This is an intermittent pilot type deal? Must be ancient.

[smasher711]

Be sure you have it grounded and polarity correct