JustAnswer
>
HVAC
Ask A Question
|
Register
|
Login
|
Help
HVAC
Ask a HVAC Question, Get an Answer ASAP!
Have your own HVAC question?
HVAC Technicians are Online Now
characters left:
Not a HVAC Question?
Related Hvac Topics:
Gas
,
Hot
,
Led
,
Code
,
Cold
,
Door
,
Heat
,
Info
,
Part
,
Type
Question
I own a six year old Trane XR-80 furnance. Last week I realized when I awoke one morning and the house was COLD that the furnace was not working properly. I see that the CNT-3798 control board has an LED on it and it is flashing. Being an EE myself, I must assume that the fact it is flashing a three dot sequence has a diagnostic meaning. Since none of the info I was originally left with tells me what that means maybe one of you folks out there could enlighten me. I have no problem working on the unit myself but I need some specifics.
Submitted: 344 days and 14 hours ago.
Category: HVAC
Value: $15
Status: CLOSED
+
Read More
Posted by
coolman1973
344 days and 13 hours ago.
Answer
Hi, did u look at all the stickers in the furnace and on the inside of the blower door?
344 days and 13 hours ago.
Reply
Yes, there is nothing to explain the LED blink sequence. I was hopiong that someone here would ahve had the info and could tell me
what the LED is trying to tell me.
Posted by
coolman1973
344 days and 13 hours ago.
Answer
why dont tell me what happens when to start it? sequence of operation
344 days and 13 hours ago.
Reply
When it first starts, a small motor starts, then you normally can hear the burners kick on, then the main blower starts. What happens now is the small blower starts, but you never hear the burner kick on. It retries several times before shutting down. Then the sequence starts again. It does occasionally work, but that seems to happen after it thoroughly cools down. I must assume it is some sort of thermal problem, as once it gets hot it refuses to operate but I'm just not sure.
What do you think, is a new control board in order?
Posted by
coolman1973
344 days and 13 hours ago.
Answer
what type of ignition system does it have, spark or hot surface, and after the inducer motor starts do u hear or see this ignition system try to work
344 days and 12 hours ago.
Reply
It is an electronic, pilotless, ignition. It does sound like the ignition trys to start but does not. As I said it seems to be a temperature related failure. I'm wondering if their could be a heat sensitive part in the circuit board.
Posted by
coolman1973
344 days and 12 hours ago.
Answer
when u hear that sparker u shoul then hear the gas valve click in, if not retry and put a meter on the gas valve terminals and see if u have 24 volts when its trying to start. if u dont then u have a control board problem, if u do then ur gas valve is failing. those blinking lights or most likely a ignition lockout code
344 days and 12 hours ago.
Reply
Thanks for your help. I'll give that a try.
Accepted Answer
sure no problem
Expert:
coolman1973
Pos. Feedback:
95.9 %
Accepts:
Answered:
12/13/2008
Hvac tech and Mechanic
15 yrs field exp/5yrs supervisingexp/ Nate and Epa cert.
+
Read More
Related HVAC Questions
I have a Carrier home central air conditioner model 38CK0423...
i have a carrier air conditioner installed in august 2004.
i have a upflow high eff lp furnace out in my garage it is
Could you suggest an annual maintenance schedule for old boi...
My Trane XE 60 runs its blower motor nearly all the time.
The AC fan in the house has stopped working. It does not tur...
My A/C unit is not working. The fan in the unit outside is
my ac amana pgd 3607 will not run fan or anything checked br...