Suburban 3500 RV Furnace With A Failed High Limit Switch

Certified Mobile RV Technician, Darren Koepp, walks you through the path that the 12 volts takes to allow this Suburban 3500 RV furnace to function. After changing the high limit switch, the furnace was functioning normally again.

[morethislife]

Awesome video and input, thank you! Our furnace runs fine for a little while, then won't kick on. If we reset it (leave off the thermostat for 3 minutes), then turn it back on, it will kick on immediately and run normally for a while again. I hope the probably is as little as this.. :-)

[hrodgers]

My problem was from the mice they had before I bought this unit. They had chewed the water heater wires ( all of them) so I had to add wire and chewed the heater igniter wire and the thermostat wires. Thank you for the videos they really help a lot. I was a auto tech for 21 years and I grew up helping my daddy after work working on appliances and home wiring. Thinking about getting my certification for RV and campers since I’m living in a RV Park anyway.

[mrblueskynm]

Excellent! I have the SF-35Q Model installed in my 2019 Outdoors RV and this is likely the culprit, or the sail switch. Both are inexpensive and simple to replace, so I'm going to buy one of each. I've replaced the limit switch on clothes dryers before, very similar. Thanks for the video!

[slangston]

I have suburban SH35 saw your video found the high limit switch had 12v on one side and not the other. Tapped the switch a couple times and the ignitor started order new high temp sensor. Thanks for the video

[paulontheroad]

Intermittent conditions can be a real headache. Thanks for an informative video!

[djgodden]

Great information. I have an RV which looks alot like the one depicted here with the furnace in the same place. Furnace was blowing but not lighting and then turning off. Checked the limit switch jumper idea and POOF... it worked fine. So, faulty limit switch! Thank you so much!

[KJRitch]

I have a new Tiffin motorhome purchased last summer and from the first time I turned on the Suburban SF 30 furnace I notice the burner keeps relighting every 2 to 3 minutes. The fan stays on. From cold the furnace burner lights and 2 1/2 minutes later it turns off. After 1:40 minutes the burner relights. This pattern continues until the thermostat sees the desired temperature is reached. Is this a high limit switch issue? Thanks

[SoildFrameworks]

Perfect just what i needed thank you sir for saveing me some money

[jasonbrewer]

Awesome channel man!!! I just recently purchased a used travel trailer that needs a lot of work. I have gained a lot of knowledge watching your videos so thank you! I have one question for you at this time. I am looking to slide my furnace over 2 to 3 in and I am wondering if they make any intake and exhaust pipes with elbows to accommodate the move. I have not seen anything like that but like I said I am new to travel trailer camping. Thank you in advance for any answers. Keep up the good work!

[ronaldporter]

love your videos. straight to the point and very helpful. can a limit switch fail and cause the furnace to overheat? mine gets really hot to the point where you can't touch the furnace cabinet. what should the temperature be coming out of the ducts? the furnace works fine other than that. thanks

[lolmaugh]

Had the whole furnace pulled out till i seen this....now i have to wait for my parts.

[Tom-muzy]

I have a Keystone Laredo and I can access the heater compartment but can not figure what holds the furnace to the floor. Of course, all the important parts of the furnace are facing away towards the compartment back wall. I really don't want to drop the all season bottom cover to find out whether or not the unit is screwed in from below.🙄

[richardhudson]

My Atwood 8531-IV DCLP has an air flow/limit fault problem, but the fan casing isn't loose and so can you please tell me how to fix the air flow/limit fault so my furnace will start working again.

[briansack]

Can a bad lomit switch also cause the furnace not to shut off regardless of where the wall thermostat is set?

[petemccammon]

Darren I enjoy your videos, they are very informative. I have a NT 30 SP Surban furnace, I am mechanically inclined and my question is which of the there or 4 with control board is more likely to work sometimes? I have already cleaned the sail switch of debris and the blower fan. I ran it 4x and it fired right up, then quit, failing 4 times. Today 1st time it fired right up again? I bought a new electrode and limit switch today but haven't installed yet.

[oldbuzzardvideo]

I just stumbled into this great resource.. Thank you! Do you happen to know if Suburban is having trouble with furnaces going over-temp and locking themselves out? Ducts are all open and the number of ducts are in compliance with Suburban's spec. I have registers at 140, 130 and 120 degree temps. The furnace shuts its self down and locks it's self out before satisfying the T-Stat. The trailer manufacture says "That shouldn't happen". My RV Tech says but an extra duct run it. It's a brand ne Grand Designs 25G with the Suburban SF30Q.. I can't get the Tech to check voltage right at the fan.... Do you bump into over temps and what is the common remedy? BTW, , Guys that talk ANDs and OR's got to be real techs!

[hilham]

I have a stupid question. I have the same furnace and and was told you have to light the pilot on these but when I went to search where to light it I couldn't find anywhere, so are these self lighting?

[jayneal]

I have an suburban furnace and when the thermostat is on Tue heater fires up bit it makes a very loud clicking sound the furnace works fine but the loud clicking when I turn the thermostat off the clicking stops the fan is still turning for the cool down just no clicking

[dakotagrown]

My furnace will work and kick on and get up to temp in the rv but then won't kick back on unless I turn it to off setting and then turn back on. I replaced the thermostat

[pamelatappan]

Great video, but it would have been nice to see you remove the switch and then replace it. Thanks.