How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Phil Your Own Question
Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
23932409
Type Your HVAC Question Here...
Phil is online now
A new question is answered every 9 seconds

Blower comes on nothing else it's a decare oil furnace

Customer Question

Blower comes on nothing else it's a decare oil furnace
Submitted: 1 year ago.
Category: HVAC
Customer: replied 1 year ago.
Duncane Furance
Expert:  BillyHvac replied 1 year ago.

hello,..do you mean the oil gun blower or the circulation blower?

Customer: replied 1 year ago.
Circulation blower
Expert:  BillyHvac replied 1 year ago.

Thank you....and when the blower comes on nothing else runs? Like the unit heat is locked out and the blower runs nonstop?

Customer: replied 1 year ago.
Expert:  BillyHvac replied 1 year ago.

thank you...do you know what the "limit" is? Is there a chance the filter was plugged when this first started?

Customer: replied 1 year ago.
What filter oil or air
Expert:  BillyHvac replied 1 year ago.

Air filter...if it were plugged we could have tripped the limit switch...

Customer: replied 1 year ago.
Where is the limit switch
Expert:  BillyHvac replied 1 year ago.

what model number Ducane do you have and I can direct you to it

Customer: replied 1 year ago.
DOUA84/95F4-AEG I sent it first
Expert:  BillyHvac replied 1 year ago.

with the top door off...you will see the oil burner gun...above that mounted on the front wall will be the limit switch

Customer: replied 1 year ago.
If u mean we're the green is I tried that
Expert:  BillyHvac replied 1 year ago.

I do not show green....can you post a picture of the unit and I will circle it. And by chance do you have a meter?

Customer: replied 1 year ago.
I have a control brand for the blower
Expert:  BillyHvac replied 1 year ago.

yes...but the limit is not part of the board

Customer: replied 1 year ago.
How to attach a photo?
Expert:  BillyHvac replied 1 year ago.

there should be an attach file link...or a picture of a link....you can also use file share sites like tumblr, mediafire.com anf flickr..photobucket etc

Customer: replied 1 year ago.
Did you get the photo?
Expert:  BillyHvac replied 1 year ago.

directly to the left of the round inspection door in center...I can barely see an edge...can you show me the entire front?

Customer: replied 1 year ago.
Photo attached
Customer: replied 1 year ago.
Another view.
Expert:  BillyHvac replied 1 year ago.

left side flat plate..size of credit caerd..2 red wires....tap it first see if blower stops

Customer: replied 1 year ago.
Blower stayed on
Expert:  BillyHvac replied 1 year ago.

remove those 2 red wires...inset a short wire into the ends to jump them together...or a small nail...just something that can metal of the wire touch the other wire...just a loop minus the switch for now.

Customer: replied 1 year ago.
Jump them blower stayed on
Expert:  BillyHvac replied 1 year ago.

with a voltmeter do you 24v at terminal R and C on the board?

Customer: replied 1 year ago.
No voltmeter
Expert:  BillyHvac replied 1 year ago.

On your unit there are very few things that can cause no heat with blower running..

Open limit switch, which we bypassed

Bad transformer..which is the square cube looking thing below the flat plate..this has 120v in and 24v out.

Do the 2 red wires from the flat plate both run to circuit board

Customer: replied 1 year ago.
is that it could it bee the board
Customer: replied 1 year ago.
What now
Customer: replied 1 year ago.
Please help
Expert:  BillyHvac replied 1 year ago.

do R and C have 24 volts?

Customer: replied 1 year ago.
I have 24 volt AC
Customer: replied 1 year ago.
At C n R 24 volts
Expert:  BillyHvac replied 1 year ago.

thank you....and what about W to C? Then we can get you wrapped up

Customer: replied 1 year ago.
the same 24 C n W 24volts
Expert:  BillyHvac replied 1 year ago.

ok, now on the oil burner assembly...is there a T and T terminal with thermostat wire attached or a jumper on them?

Customer: replied 1 year ago.
Nothing
Expert:  BillyHvac replied 1 year ago.

On your circuit board...is there a yellow blade fuse, like what is found in a car?

Customer: replied 1 year ago.
n it's good
Expert:  BillyHvac replied 1 year ago.

And to recap...I know we did look at it....you did jump out the limit with 2 red wires on the flat plate?

And what circuit board model number is *****?

Customer: replied 1 year ago.
ST9103A 1069
Expert:  BillyHvac replied 1 year ago.

the only item in the schematic that can do this is the limit...if we have 24v at w and c...then the limit is the only item that can cause this....have you checked the red wires to where they plug into the board in the connector?...

Customer: replied 1 year ago.
I just too jump the limit again nothing
Customer: replied 1 year ago.
Circuit board was bad

Related HVAC Questions