Elk Ridge 37 Ulta furnace problem

Tried using our furnace this weekend. It will not do anything. I put the controller (Dometic) into furnace mode, raised the temp up to 90 and the blower for the A/C kicks on? I put the fan into Auto mode and nothing happens. It appears as thought there is a toggle switch on the furnace itself and it appears to be in the on position?

Thank you!! :mad:
 

cookie

Administrator
Staff member
So let me get this straight.
Do you have a digital thermostat?
You scrolled through the menu in the thermostat and set the fan to 'Auto'.
When you did that the fan on the AC unit continued to run.
Did you have heat?
Silly questions, but do you have propane in your tanks, and are they turned on?

Peace
Dave
 

danemayer

Well-known member
Spencer387,

Sounds like you've solved the part of the problem involving the A/C blower by putting the thermostat fan setting on AUTO. If you want it to run all the time, set it on HIGH or LOW. You would usually only do this when you want air circulation in the summer.

Some clarification would help on the rest of the issue. "Nothing happens" is a bit vague. But if the furnace blower doesn't start, I would say you might have 1) a problem with the thermostat, 2) a failure at the relay between the thermostat and blower motor, 3) a blown 12V fuse, 4) a problem with the blower motor.

The fuse is most likely and easiest to check.

Here's the normal sequence for furnace startup.

SEQUENCE OF NORMAL OPERATION
1. When the thermostat calls for heat, the blower motor is energized immediately.
2. As the blower motor reaches approximately 75 percent of the normal rpm
(within 3 to 5 seconds) the microswitch, in response to the air flow, will engage
allowing current flow to the solenoid valve and the spark ignition system.
3. The current to the valve opens it and allows gas to the main burner. The spark
then ignites the main burner.
4. After main burner ignition, the flame detector will sense the presence of flame
(usually within 7 seconds) and deenergize the lockout feature. If the main
burner does not ignite or the flame detector does not deenergize the lockout
feature within 7 seconds, the unit will go into lockout. At this time, it will be
necessary to set the thermostat on OFF and repeat steps 1 through 6 of the
lighting instructions.
5. After three (3) attempts with no ignition or main burner continues to go off
within 7 seconds, go to shutdown and determine cause. (see service hints)
6. If within a period of approximately 2 minutes after the main burner is lit, the
thermostat is turned back, both the blower motor and solenoid valve are
deenergized. However, if the furnace continues to run longer than 2 minutes,
which it normally should, a slight snap can be heard from within the casing. The
snap is caused by the fan switch as it changes its position. After this occurs, if
the thermostat is satisfied or turned back, the solenoid valve will close, the flame
o n the main burner will go out, but the blower will continue to run for a short
period of time and will then shut off. The purpose of this is to remove most of
the remaining gases from the heat exchanger. Be assured that this period of
blower override is a part of the unit’s normal operation.
 
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