Suburban Furnace In 2001 Monaco Dynasty

7 posts in this topic

When mode is selected to furnace, all I hear is a click at the furnace. All fuses are OK. Unit does not have exterior access, only from under the fridge.

How difficult is it to remove this unit for further testing? It appears very difficult to remove this unit?

Any experienced Suburban furnace removers out there?

Getting cold here in British Columbia....

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747 guy,

Does the blower motor start?

If the blower is running and blowing cold air, I have a feeling the sail switch in the blower assembly is hanging up or has failed.

Could you post the model number of you furnace for the group also.


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Yes, the question is how far into the heat cycle it gets. In order, these things happen:

Thermostat clicks sending "turn on signal" to the furnace.

Fan starts

Fan moves sufficient air that the sail switch is closed, signaling the PC board to spark ignitor and open gas valve

Ignition takes place, burner on-- thermocouple/ignitor sends "flame sensed" signal to PC board so gas valve stays open.

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Yes I do have a SF42F.....thanks Walt.

The blower motor does not start.

I do have 12 volts on red wire.

The reason for my question was to confirm how to get the unit out from underneath the fridge. Lots of ducts and sealant blocking easy removal.

It appears the control board is back closest to the skin of the coach, at least that is where the wires go.

Do the guts of the furnace slide out of the case by removing the outside inlet and exhaust flanges?

I am asking all these questions hoping for something simple that I have overlooked as the solution.

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Looking at the trouble shooting information that Walt supplied the link for, on page 4 / page 9 printed on bottom of page.

It looks like one accesses the furnace by removing the outside cover and the required parts to get to the circuit board and blower assembly. Should it be installed with the extensions, then one would need to remove unit to get to the back. Check the drawings for your setup.

They do not make getting to some of the items easy!

Look at the flow chart on page 14 as printed on the bottom of the page / or page 9 on the page display window.

The PDF version looks to be a copy of only some of the pages from the original manual!!

Follow it through the indicated steps.

You did mention the the blower does not start and that is the first step in the sequence up to the point the furnace flame lights.

Tried to copy Step A page18 / page 13 from the header bar.

If section does not copy over. Look at item # 4 and 5. the key might be locating the defective relay if that is the case or replacing the motor.

The other issue could be an open circuit brake or fuse mentioned in the information.

Figure 16 on page 16 shows the time delay relay that could be bad and it would keep the blower motor from starting. Once the blower starts the sail switch should close and the furnace should come on if everything else is in order.

Download the information at this link. Looks like what you have described in your post.



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Thanks Rich for taking the time to answer in detail. It appears that I am going to remove the unit for troubleshooting by pulling the Insides out.
I put the coach in heated storage yesterday and we are off to Costa Rica for the winter.
I will report back next spring when I return to tackle the problem.
But wait a minute.......it will be spring and I will not need the furnace, so maybe I will just add it to my TO DO list.

Thank you all for educating me in the sequential operation of the system.

Till the spring!!!

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