Furnace blower not working

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Cooper AK

Member
Joined
Mar 23, 2016
Posts
6
Hi everyone,
The blower on my suburban furnace is not coming on. Consequently, I have no heat. It's March and I'm in Alaska so it's a little chilly!
When I activate the furnace at the digital thermostat I can hear it "click" as normal but the blower does not come on. The fan and A/C have the same controller as the furnace. They both work fine. I have checked all fuses (that I know of) and all appear to be in working order. Now I am at a loss.
Oh, I do have propane and the stove is working if that helps.
Any ideas???
Thanks! 
 
You can remove the cover from the thermostat, select heat and with a voltmeter check and see if 12V is placed on the lead  to the furnace after you  hear the click. If no 12V is present, try placing a jumper from 12V+ to that particular wire to the furnace and see if that starts the furnace. (the thermostat runs on 12V).

Make and model of both the furnace and the thermostat  might help with further diagnosis. (On some Coleman Mach thermostats, there are two sets of wires from the thermostat, a cable of 6 leads or so (for air conditioning)  and a group of 3 leads. In the group of 3 there are 12V+ 12V- (power supply for the thermostat) and the lead to the furnace (labeled W on mine). You may have to take the thermostat off the wall and pull the wiring out a bit to identify it correctly.
 
It's a 2012 spring dale. 267bhssr.
I've got 13+ volts at the battery.
12+ at the thermostat IF I'm doing it correctly. That's a big if.
Tstat is a digital Dometic. Furnace is a suburban sf30fq.
 
Just the little silver vent.
The furnace is located under the refer with enough room for one handed work. I got the furnace out after a few hours of frustrating labor. I had to remove the housing as well. The blower seems to turn easily at this point. I'm leaving town today so I wont be able to test for power or the sail switch until I get back on Tuesday. Anyone have any tips on testing these?
 
10 to 1 says it's a SF-XX-F model. Pretty simple machines.

It won't be a sail switch because that's later in the system of operations. You either have a Time Delay Relay or a Module Control Board. I hope you checked for power to the furnace before you ripped it out. If not, that's the place to start. Also, it's not unheard of for the power switch on the furnace to just have been accidentally switched off.

If you have 12VDC at the fan, but it's not running, replace the motor. Good luck with getting the squirel cage off, they're difficult sometimes. Spray it down with PB Blaster a few days before if you can.
If it's a time delay relay, you want to test for power before and after the relay. Pretty good chance that it's the bad part. Cheap, easy replacement.
If it's a board with built in time delay, check for voltage at the board and if it has an on-board fuse. If it's got good power, but no voltage at the fan, then you'll need to replace the board.
 
    Coop, like I said to you in the Virtual Campfire, this is the best place to get help.  I knew the gurus would show up and give you good specific advice.  These guys are the pros and can tell you step by step how to fix it.

Ed
 
Check out my article on Furnace Troubleshooting in the forum Library at http://www.rvforum.net/miscfiles/Furnace_Trouble-2.pdf

It's written using an Atwood as the example, but the Suburban is essentially identical in operation.

If the fan motor doesn't start running at all, odds are it is a 12v power problem to the furnace or the switch that NickB mentioned. First thing to test is the fuse and that switch.A bad motor is the next possibility. The fan motor is just about the first thing to start up and even the circuit board isn't much involved until the fan is spinning.
 
Is it blowing the fuse to the heater/fan blower?  I had a case a couple of years back where mud-dabbers got into the squirrel cage thru the exhaust vent holes and built a mud/nest.
I pulled the unit out far enough to get at it to clear out the nest. Then got some of the little screens from Camping World to screen off the input and exhaust holes.
 
azwinne said:
Is it blowing the fuse to the heater/fan blower?  I had a case a couple of years back where mud-dabbers got into the squirrel cage thru the exhaust vent holes and built a mud/nest.
I pulled the unit out far enough to get at it to clear out the nest. Then got some of the little screens from Camping World to screen off the input and exhaust holes.

My furnace would not work this morning, so I am doing some research before trying to troubleshoot this evening.  My owner's manual is about useless, but it does say not to install any screens over the furnace vent.
Why?
I can see one wasp nest and another mud dobber tube that I will clean out tonight.  The screens seem like a good, easy prevention.
 
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