Suburban Furnace Blower / Startup Issue

antsing · 02-03-2013, 09:47 AM

Hi folks,

Just brought home my first RV...a 2013 ROO 183. I have been getting familiar with it here at the house before our first planned trip in March. Yesterday, I ran into an issue with the furnace...a Suburban NT-20SQ.

After plugging in shore power, opening the LP valve, and closing the battery disconnect switch, I started the furnace by moving the Suburban thermostat from "off" to the midpoint between off and "warmer."

After normal startup and running fine for a few minutes, I lost the shore power connection (GFCI tripped in the house) and the blower began a series of strange sounds as it wound down, at which time I switched the thermostat to "off."

I then restored shore power, but the furnace will not start. I have followed all directions in the owner's manual and it will not start. The blower will not kick on. The furnace makes a clicking sound twice after moving the thermostat to on but the blower does not start and the furnace does not ignite.

Any help in troubleshooting would be greatly appreciated.

firephighter · 02-03-2013, 10:11 AM

Have you looked for a tripped breaker in your Roo? Sometimes when a ground fault is tripped it will trip the breaker it feeds (not always, sometimes). Do you hear the induction fan blowing while it is trying to light? If you do not, then you have a power issue.

antsing · 02-03-2013, 10:14 AM

Thanks, I should have mentioned that there are no tripped breakers, and no blown fuses on the breaker panel. The induction fan does not start either. Could there be a fuse within the furnace itself?

firephighter · 02-03-2013, 10:21 AM

I am not certain of a fuse hidden out of sight. It would be unlikely. If it is possible, see if you still have power to the furnace. Need a voltmeter. Just asking, did you turn the gas off while resetting your GFIC and forget to turn it back on?

antsing · 02-03-2013, 02:46 PM

No, I did ensure LP was on.

Goomph · 02-03-2013, 02:54 PM

The weird sounds it made .. Did it sound like the furnace fan was turning off and on and of and on and off and then silence ? That is how mine died.

antsing · 02-03-2013, 03:01 PM

That would accurately describe the sounds it made. I was thinking the blower motor died as well, but I want to rule out any knucklehead newbie mistakes I might have made.

Goomph · 02-03-2013, 03:46 PM

I am waiting till spring to take out the furnace and have a look at it. I looked at the inside of the furnace as much as I could with an extendable mirror and could not see a fuse at all inside the unit. My guess is either the fan motor died or the control board died. i checked and there is proper power to the unit and the thermostat wires are working as well. Good luck ! We should let each other know if/when we find a solution.

antsing · 02-03-2013, 03:48 PM

Will do. Thanks for the info.

FarmerJim · 02-03-2013, 10:31 PM

Have you checked your 12 volt fuses ? Although you were plugged into 110 AC the furnace runs on 12 volts . The 110 AC just powers the converter to make 12 volts DC and charge your battery (if your battery is dead ). If your battery is charged you don't need "shore power" to run your furnace ! Jim

antsing · 02-04-2013, 05:56 AM

Thanks, Jim. I didn't realize the the blower is always running on 12V. Is there a fuse in or under the unit? Because none are blown on the breaker/fuse panel.

**huntr70** · 02-04-2013, 06:40 AM

If the blower stopped when you lost shore power, you probably have a dead battery.

Pull it out, and charge it. The blower won't work if there is low 12 volt voltage.

FarmerJim · 02-04-2013, 03:46 PM

Quote:

Originally Posted by antsing

Thanks, Jim. I didn't realize the the blower is always running on 12V. Is there a fuse in or under the unit? Because none are blown on the breaker/fuse panel.

You said "breakers" those are 110 volt . You may have a 110 volt breaker partially off , try flipping all of the 110 volt breakers hard to off then flip them back on . Just to be clear are you also checking your automobile type 12 volt fuses ? Jim

antsing · 02-04-2013, 04:00 PM

Yes, all fuses are good and I reset all breakers. Just took it back to the dealer and it looks like a failed blower motor. Thanks for all the tips!

FarmerJim · 02-04-2013, 05:36 PM

Glad your dealer is taking care of this . Please update us on what was the cause and the fix as we all learn from this forum ! Jim

Goomph · 02-04-2013, 06:10 PM

Great, that is what I am looking at too then .. at least It is very strong indication of the problem as they failed he same way.

antsing · 02-06-2013, 08:58 PM

Well, I just picked up the Roo from the dealer. During troubleshooting, they were not able to get the blower to work. So the removed the furnace and hooked it up to 12V and gas on the repair bench. After pulling it apart, they determined the sail switch was stuck. Switch was adjusted and several optests were satisfactory. Upon reinstallation, no further issues were found and the unit works properly. I will run it this weekend to make sure.

Thanks to all for sharing your insight and experience.

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