Furnace blower?

[Zach]

Good morning,
Luckily I got the winterizing done over the weekend...it's been below freezing every day since!! I thought I'd keep the RV plugged in all winter but yesterday I realized the blower was kicking on, even though the thermastat was turned all the way down. I then shut the propane off figuring this would prevent the heat from coming on, which it did, but the blower would still come on. Not sure how this works should there be another place to shut the blower off?
Clueless in Mass.
Zach

 

[Lowell]

There shoule be a position on your thermostat to turn the furnace off.  When switched to off, the fan will not run.

 

[Zach]

Hi Lowell,
Thanks for the quick reply. On my thermastat there's an upper and lower "slide" both are all the way to the left in what i consider the off position, but the blower is still coming on...any reasons for this?
thanks,
Zach

 

[Lowell]

On my thermastat there's an upper and lower "slide" both are all the way to the left in what i consider the off position, but the blower is still coming on...any reasons for this?

If "off" isn't identified, you might try them both in the center position. Some thermostats have heat on one side, AC on the other side and "off" is in the middle.  good Luck!

 

[fredethomas]

Don't know what system you have for the furnace control.  There are several types.  Dometic has a lever switch on the bottom underside to the control that turns it off.  You might have to pull a DC breaker.  The fan is DC.

 

[Jeff]

Our Dometic also has a switch on the front of the furnace that shuts the system down for maintenance. It would require pulling off the outside cover but might work if you cannot find the proper fuse.

 

[Scoundrel]

When all else fails..pull the fuse.

 

[Karl]

O.k., how about this: the overtemp switch is stuck. Just like when operating correctly, the blower will keep running until the combustion chamber/heat exchanger is cool enough to be safe. That would keep the motor running regardless of how the thermostat is set. Open up the outer compartment and there should be a wiring diagram and parts location diagram somewhere in there. If it's not the thermoswitch itself, could be the control board.

 

[rclark]

I have a '94 Pace Arrow and the thermostat has a little on/off switch on the bottom, left side!! It isn't marked on the front or top, so you might check it!!

Randy

 

[Gottasmilealot]

Turn off the breaker at the electric panel.

I had a problem with my furnace blowing cold, not lighting right etc., and it ended up being the connector accessible from the outside removable panel. The contacts must have gotten a bit corroded or tarnished.  I unplugged and replugged in the connector a few times, and it's been fine ever since.

 

[Karl]

Keith,
The furnace will be fused; not breakered. It runs off 12V exclusively.

 

[Gottasmilealot]

Mine has a dedicated breaker for the furnace. It probably has a transformer to step it down to 12 volts for when the RV is running off line voltage when plugged in.  The relay would switch it over to the house current supply if plugged in. You're correct in that there should also be a 12 volt fuse in the line between the relay and the motor to protect the 12 volt line when the blower motor goes bad and draws too much current for the supply line.

When troubleshooting mine, I couldn't figure out why the blower ran and blew cold air if the burner didn't light.  The ignition sensor wiring must run through that connector where I located the bad connection problem.

For once a simple solution that cost me nothing worked.  I had envisioned a major furnace cost when it was just the connector contacts that needed a little cleaning. The point of my post is to remind others to not overlook the simple things and assume the worst.

 

[Karl]

The point of my post is to remind others to not overlook the simple things and assume the worst.

Very true, and a corroded connector can be a real bear to find. I'm a firm believer in dielectric grease and use it whenever I have a connector apart and it doesn't already have some inside. Clean first, of course.

 

[Zach]

Thanks for the all the replies, I did figure out that it's not on the circut breaker...now I'm in search of the fuses...wish me luck.
Zach

 

[172ndLIB]

If you pull the cover off your t-stat you will see how it can be turned off.  Some the little switch on bottomgoes to the left some to the right.  Wit it open you can see which direction opens the contact points.  If the furnace is still running with the contacts open then there is another problem.

 

[RLSharp]

If the furnace is still running with the contacts open then there is another problem.

Not necessarily. When the thermostat is satisfied, i.e. the ambient temperature has reached the set temperature, the thermostat contacts open but the furnace blower continues to operate until the internal temperature of the furnace reaches the "cool down" point. THEN a set of contacts in the furnace open and the blower stops running.

 

[Zach]

So I finally figured the furnace blower out...the on/off switch is at the bottom of the thermostat control and I thought it was in the off position, so thought my problem was solved. Then I found the blower running again, turns out the switch wasn't really off, it needed to be "clicked" to the left even more...problem solved.
Thanks guys,
Zach
PS> I learned another valuable lesson as well. To stop it from running at first I unplugged the RV from the house, all this did was to keep the blower running on battery power, so this drained the battery all the way down...the good news is the battery is recharged and the furnace blower is actually off.

 

[Shayne]

Glad you found the problem.