Suburban sf30 furnace

[Mn_camper_guy_]

I have a 2015 suburban sf 30 furnance that I used only one season. I went to use it this year and day two into a week all trip furnace quit working. I removed and found ignitior wire had burn off. I replaced it and ran one night and did it again. I couldn’t find any wires shorts and removed burner half the holes were full and closed with soot. Anyone have a idea what wrong? I think it running to long and getting to hot inside chamber but that’s just my thought.

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[Davidlee64]

After verifying no insect "homes" in the intake and exhaust ports (to outside of unit) then If you have the service manual, look up the "Main Burner Orifice" to see where it goes and verify it is in place and didn't vibrate loose and fall out. This could cause the problem you seem to be having.

[shastagary]

if its melting wires off did it also melt this? Suburban 350184 Combustion Air Wheel

[dougrainer]

Don't take this wrong. You have NO idea how a SF works. You have No idea what to do. You NEED a professional to look at the Furnace. You think it is EASY to diag and fix a furnace and you are the poster child for how it is NOT easy to do. I will bet the furnace motor is either NOT up to correct RPM or you have a Impellor problem with getting the correct amount of air to the combustion chamber. For a PROFESSIONAL, diag and fixing your problem is easy. Doug

[Mn_camper_guy_]

Well it might not be a blower fan it the motor that brings the air in before the gas valve opens then once it flames on for a few seconds the blower sends heat into camper. I have only unplugged the wire for igniter flame sensor sense it acts as one otherwise it’s the way it was from dealer. If no defects way when I go on site to price board it said the part as changed order this part number. I don’t know what to think it’s get correct power and gas everything seems to work as it should except it burns up the wire and soots burner. Like I said only have used it for one deer season before this happing just a drag paying 35,000 and getting days days out of a furnace.

[PaulJ2]

Agree with Doug. Two things here are giving me a clue.
#1: If the burner impellor is not forcing the flame back into the burner tubes where it belongs it will flame up and burn up your ignitor wires.
#2: That would also cause soot build up like you said.
Any chance that the furnace wires are reversed causing the blower to run backwards?

[dougrainer]

Mn camper guy! wrote:
I have no clue if it’s coming up to speed when it came on blower starts flame comes on and within a short period furnace blower comes on. Chuck V1 said his did same thing and they replaced his circuit board. I look at boards online and it looks like they discontinued the board and replacing with a different one . It makes me wonder if Suburban knows it’s a problem and not saying. I feel once you start replace boards with different ones there must be a problem.

There is NO design defect in the SF series. What you stated above does NOT make sense. The blower comes ON. PERIOD. Once the blower comes ON, the impellors are turning and the Sail Switch CLOSES, and this tells the module board that the Blower is indeed running. Once that happens, the gas valve opens and at the same time the Piezo Ignitor sparks and lights the burner. Once Flame is detected, the furnace stays lit until the tstat is saitisfied. NO OTHER BLOWER COMES ON. THERE IS ONLY THE ONE BLOWER. Doug

[Mn_camper_guy_]

I have no clue if it’s coming up to speed when it came on blower starts flame comes on and within a short period furnace blower comes on. Chuck V1 said his did same thing and they replaced his circuit board. I look at boards online and it looks like they discontinued the board and replacing with a different one . It makes me wonder if Suburban knows it’s a problem and not saying. I feel once you start replace boards with different ones there must be a problem.

[PaulJ2]

Sounds like not enough air to the burner. Does the blower that feeds air to the burner come up to speed? Usually motor drives two blowers, one for the burner and the other warm air for the camper.

[Mn_camper_guy_]

Thought maybe the high temp sensor was letting it run to hot and that’s why the spark wiire burned twice! Like I say camper is almost new furnace as only been use 6 days before the wire melted and like I said installed new igniter and that burned the first time it was used.

[dougrainer]

SF 30 is more than large enough for a 25 ft RV. You are talking about the Ignition wire that goes to the SPARK electrode? Not the Hi temp sensor wire? Since you have stated it, I would replace the Hi temp sensor. They are very cheap. Soot indicates that the fresh air is NOT getting to the combustion chamber, hence it runs rich. Doug

[Mn_camper_guy_]

dougrainer wrote:
1. In 38 years as a service tech, I have never seen a Ignition wire burn/melt off
2. To have 2 do it, points to you having a severe Insect infestation. NOT a defective Furnace
3. The soot is caused by burning LP without enough air. The furnace is designed to have the correct air/LP mixture and there is NO adjustment
4. You problem as I stated is the Interior chamber is clogged with Insect mud nests and insects. You need to disassemble the furnace and clean it out. I disassemble and run water thru the chamber and you will be amazed at what comes out that you cannot see. You must do this and then reassemble and run the burner to evaporate any moisture left in the chamber. Doug

I cleaned it out and no bugs came out at all. I ran water through it. I thought the heat sensor in the front might be defective and was getting to hot only burns the wire to the point where it exits the furnace wall. Like I yes sense new it’s only been run 6 times but it seems to run a long time before it shuts down and turns back on with in minutes and runs half hour easy before it shuts down again. Uses a lot of fuel. Like it’s to small for the 25’ 5th wheel does have cold weather packages.

[dougrainer]

1. In 38 years as a service tech, I have never seen a Ignition wire burn/melt off
2. To have 2 do it, points to you having a severe Insect infestation. NOT a defective Furnace
3. The soot is caused by burning LP without enough air. The furnace is designed to have the correct air/LP mixture and there is NO adjustment
4. You problem as I stated is the Interior chamber is clogged with Insect mud nests and insects. You need to disassemble the furnace and clean it out. I disassemble and run water thru the chamber and you will be amazed at what comes out that you cannot see. You must do this and then reassemble and run the burner to evaporate any moisture left in the chamber. Doug

[Mn_camper_guy_]

SidecarFlip wrote:
Sounds to me like it's burning way too rich for starters.

Is there anyway to adjust furnace for it being to rick? I’ve already cleaned. I’m a little disappointed that I only used furnace three weeks before this and already having problems of course after warranty runs out over 30,000 spent on it and only get six days out of a furnace that I’ll 400 into once I’m done! Shame! I’m sure hoping it the board.

[SidecarFlip]

Sounds to me like it's burning way too rich for starters.