Intermitted gas furnance problem

hvacfdoctor

Have Amana GUID 090 in last month have replaced flame sensor, main board, roll out, ignitor, stat batteries.  

Test voltage, amperage TD,  flame signal  etc.  ALL ok

Check and cycle unit 20+ times no failures ideal condtions and operation.

Two days ago changed stat, cycled 18 times no falure  today got call out again.  Customer reset power and it ran fine. 

HAve metal conduit to unit for ground that goes back to box panel. 

Not sure what else it can be plus its intermitted problem??? 

Tim McElwain

Give me a breakdown

of the make and numbers of some of the controls in particular the control board.



Has a combustion analysis been done on the unit? If so what are the readings O2, CO, stack temp etc.

Slimpickins

check ground

Make sure you have a solid ground from the furnace junction box, to the service shutoff and to the main panel for openers.

unclejohn

If the

Furnace has a molded plug on the blower compartment shelf you can try cutting that out and wire nutting the wires togeather. Sounds like you have replaced everthing but the wiring harness.

VictoriaEnergy

Problem details

What exactly is the problem?  Does the control board blink an error code?  Does the roll out switch you replaced have a manual reset on it?  And, why did you suspect it?  Is there a manual reset on the spill switch?



Avoid guessing and replacing parts on speculation they're the source of an intermittent problem, especially expensive ones like the control board.



Inspect the draft inducer, externally and then disassemble it to look at it's condition: look for severely corroded blades, spin the wheel and see it rotates at least a full rotation after you spin it.  Look for excessive scale build up. 



Inspect the port where the tube to the pressure switch attaches near the inducer, there is often a pin sized metering port at the housing, make sure this isn't covered up with scale/rust.



On in-shot burners, look for scaling at the ends of the burner, especially where the little cross over flame runs and clean that up.

VictoriaEnergy

Problem details

What exactly is the problem?  Does the control board blink an error code?  Does the roll out switch you replaced have a manual reset on it?  And, why did you suspect it?  Is there a manual reset on the spill switch?



Avoid guessing and replacing parts on speculation they're the source of an intermittent problem, especially expensive ones like the control board.



Inspect the draft inducer, externally and then disassemble it to look at it's condition: look for severely corroded blades, spin the wheel and see it rotates at least a full rotation after you spin it.  Look for excessive scale build up. 



Inspect the port where the tube to the pressure switch attaches near the inducer, there is often a pin sized metering port at the housing, make sure this isn't covered up with scale/rust.



On in-shot burners, look for scaling at the ends of the burner, especially where the little cross over flame runs and clean that up.