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bklaes · 03-03-2019, 06:12 PM

I've got 2 furnaces. One of them the blower won't go. The other is great.

Owners manual says:
If the blower fails to operate after verifying the batteries are charged and fuses are good, use a coin or screwdriver to open outside access door. Make sure the power switch is on and circuit breaker is pushed in.

I opened the out side cover on the faulty furnace and see a red light flashing on the circuit board. So... The switch is on. Where is the fuse? Where is the circuit breaker?

Thanks!

flamebuster · 03-03-2019, 09:57 PM

I believe the red flashing light should have a pattern to the flashes, which will indicate your problem. You can google atwood trouble codes for your model and find the answer if your manual does not have the codes listed.

firedoc · 03-03-2019, 10:17 PM

Does the blower not come on st all or does it come on for several seconds and then shut off?

Old-Biscuit · 03-03-2019, 10:45 PM

DIAGNOSTIC CHART
FAULT LED INDICATION
Internal Circuit Board Failure----------------------------------Steady on, no flashing
Limit switch/Airflow problems--------------------------------1 flash with 3-second pause
Flame Sense Fault-----------------------------------------------2 flashes with 3-second pause
Ignition Lockout Fault-------------------------------------------3 flashes with 3-second pause

Combination ON/OFF CB Switch is finger size mounted on frame in outside compartment
Should be RED wires..........12V DC from DC Dist Fuse to the Switch then 12V DC from Switch to 'timed delay relay' then to motor (OR if no relay then to Blower Circuit ON circuit bd)

Follow the DC.....
Reset On/Off--CB by pushing button IN
DC thru Timed Delay Relay is trigger when T-stat Closes so DC goes to motor (same if Blower Circuit on circuit bd---needs DC from T-stat)

Some circuit bds will do a 'circuit test' 1st

If Sail Switch is Closed...then circuit bd will 'lockout'
Sail Switch can ONLY close when FAN has purged/up to speed

DC goes thru Sail Switch/Limit Switch to circuit bd which then energizes gas valve/ignition

bklaes · 03-04-2019, 05:11 AM

Thanks for quick replies.
No blower. Error code is 1 on, 3 seconds off.
Reset the Circuit Breaker switch but didn't solve it.
Old Biscuit -thanks for the path info.
I'll have to wait till it gets back in the barn to do the deeper dive.

Old-Biscuit · 03-04-2019, 08:25 AM

1X per 3 seconds.......Airflow/limit switch
That stands to reason cause motor is not starting.
1st thing to check is 'stuck sail switch'
Switch has paddle that sticks out into air stream ....if still closed no furnace function

Remove outside cover
Then remove cover over motor.....2 white wires go thru that cover and connect to sail switch
Free up the paddle......things get dirty in there and paddle/micro switch can stick

DC to sail switch.then when it closes DC to limit switch to circuit bd
Turning T-stat OFF then back ON should reset 'circuit bd lockout'

firedoc · 03-04-2019, 10:45 AM

My bet it sail switch. Quick test, tap side of cover to see if you can unstick it.

bklaes · 03-14-2019, 05:51 PM

Sorry for long delay on getting back to my own issue.
Voltage failure at corroded connections on the on-off breaker-reset switch.
And, that same switch is going bad. VERY touchy to on/off. A new one is on order.
Thanks to all.