# Sf30/f Furnace



## Santa Fe TX Bob (Oct 30, 2011)

My furnace was working earlier this year. I had to run the air conditioner first to cool down the trailer to test it as the thermostat only goes up to 90. I tried the furnace again with this recent cold front and got nothing but moving air. There is little information on servicing this unit. Suburban is like Keystone. They don't want to communicate with the people who butter their bread. I did more work than necessary as I was flying blind so offer some tips to others who may want to service their furnace. I will assume that anyone attempting this repair will have the good sense to shut off and purge the propane system and remove the furnace fuse before proceeding.

Removal:
1. Remove outside vents. Remove 6 screws and scrape vent off side of coach. It is put on with what looks like white plumber's putty. Discard cheap rusty screws and buy new stainless srews for re-installation.
2. Remove return air grill (2 screws) Remove front cover of furnace (2 screws).
3. Disconnect gas line and cut the 4 wires that run to the unit. Go back to the store for some wire. #12 red and #12 yellow for power and #18 blue for thermostat wires. While you are there get some wire loom to make your re-install look professional (unlike Keystone's original install).
4. Remove 1 screw from the bottom center of unit. It is a tight fit but you can now slide the heat exchanger assembly out of the housing. 
5. (Optional) Carefully mark the location of the housing and unintall it by removing 2 screws. You can now lift the housing slightly and snake it out of the return air hole. Go back to the store and purchase some duct tape. (Not the grey junk but the aluminum foil tape that professional HVAC personnel use) Tape over the 4 covers on the side of the housing that have been rattling and driving you nuts since you have owned your unit. (Keystone should have done this to begin with.)

On the bench:
1. Use the wire you purchased to lengthen the cut wires on the unit. You will now find that Suburban has put a wiring diagram on the unit. Something that is not available on their website. Rather than splice into the wires it would be more professional to do home runs to the wire's origin. I used 3/8 wire loom to cover the wires and discovered a place between the switch and fan that just accomodates this size of loom nicely. I lengthened my wires about 2 feet and terminated the ends with insulated spade connectors. 
2. Remove 9 screws on burner fan housing and remove the wasp nests that have accumulated over the summer. These will interrupt airflow and may cause an inefficient burn and smokey exhaust. Go back to the store and get some polyurethane caulk to patch the divot that Keystone put in the burner housing with their hole saw. I like to use 3m's 5200. Suburban recommends against putting a bug screen on the vents but I would suggest that it would be a good preventive measure. Since you now know where the switch is located on the unit you may want to install a bug screen after switching off the unit for the summer.
3. Remove gas tube from top of unit by disconnecting tube from the gas valve and removing 7 screws and 1 nut from cover housing. Be very careful not to damage fiber gasket as it is very delicate. Using compressed air blow out the gas tube in the direction of flow to discharge the junk that was clogging the gas tube. You may want to blow the accumulated rust out of the inside of the heat exchanger. Any visible mud dauber nest should be removed from the heat exchanger but when you fire up the unit the rest will be incinerated. 
4. Test run the unit to verify that the igniter is throwing a spark. Refer to your wiring diagram for color coding. Mine was red+, yellow-, blue thermostat. Connect the two thermostat wires to each other to test run.
5. Re-install the gas tube. If you have a young child available he may be helpful to start the nut into the gas valve. If you have damaged the gossamer gasket you can make a replacement with exhaust gasket paper available from old-school auto parts supplier. The chain-store (its not in the computer i don't have it but i can order it stores) may not have it.
6. Attach regulated gas supply and run the unit again to verify that you have effected repairs.

Replacement. If you have gotten this far you can figure it out.


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## Sweathog62 (Jul 28, 2005)

Very nice report. Send some pics if you can.


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## CamperAndy (Aug 26, 2004)

Attached is the SF service manual.


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## Santa Fe TX Bob (Oct 30, 2011)

I appreciate the manual. If that is the actual manual from the Suburban factory my confidence in their product is waning. Thanks also to Bryant for making it available on the net. I certainly wish that I could have gotten it directly from Suburban.


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## CamperAndy (Aug 26, 2004)

Santa Fe TX Bob said:


> I appreciate the manual. If that is the actual manual from the Suburban factory my confidence in their product is waning. Thanks also to Bryant for making it available on the net. I certainly wish that I could have gotten it directly from Suburban.


Some of it is available but the manuals as far as I know are only available to authorized service techs. Bryant have decided to put most of them on the web for general access. I do not think what I posted is the actual manual but excerpts from it.


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## Santa Fe TX Bob (Oct 30, 2011)

Suburban has sent me pdf files of the two manuals...operator...installation. I have included them in this post.


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