Forum Discussion

path1's avatar
path1
Explorer
Jan 31, 2018

Suburban gas furnace question

I have "install directions" and "user information manual" for what came with RV. Model (take your pick of which one?) sf-20fq, sf-25fq, sf-30fq, sf35fq and sf-42fq. Here is where I'm at and problem(s)

1. (has plenty of propane coming out of stove and have good elec, currently plugged in at home.)
Turn up t-stat and heater comes on for about 8 min then shuts off. I check fuses, all OK...so I dig deeper

2. Remove cover (vent to inside) and see nothing but the metal box, no model numbers and no access without removing (on the left) the inverter and on the right, cabinet structure for kitchen drawers.

3. So before I start taking things apart, I get on-line to find shop manual and can't find anything, like a technician would use.

RV is almost 5 years old, so I want to find and go thru the trouble shooting check list. (I hope all it needs is a good cleaning and I would like to see what the flame looks like.)

Anybody have any links to this model? Any help appreciated.
  • dougrainer's avatar
    dougrainer
    Nomad
    Feb 02, 2018
    path1 wrote:
    dougrainer wrote:
    You will not find ANY manual that will state HOW to remove a complete furnace from inside a RV. That install is done by the manufacturer of the RV and there is no manual on that. Doug


    Thank you...

    To work on it once removed from RV and before re-installing, I guess hook up to regulator and fire it up to test?

    Never thought about it before, but it seems so dangerous to have something with a fire it going on top of my wooden work bench. Then again lots more air gap clearance on my work bench than inside RV!


    Yes, MY test bench I use has carpet. I just insert a piece of plywood under the furnace. You are NOT running it more than 10 to 15 minutes.
  • path1's avatar
    path1
    Explorer
    Feb 01, 2018
    dougrainer wrote:
    You will not find ANY manual that will state HOW to remove a complete furnace from inside a RV. That install is done by the manufacturer of the RV and there is no manual on that. Doug


    Thank you...

    To work on it once removed from RV and before re-installing, I guess hook up to regulator and fire it up to test?

    Never thought about it before, but it seems so dangerous to have something with a fire it going on top of my wooden work bench. Then again lots more air gap clearance on my work bench than inside RV!
  • dougrainer's avatar
    dougrainer
    Nomad
    Feb 01, 2018
    You will not find ANY manual that will state HOW to remove a complete furnace from inside a RV. That install is done by the manufacturer of the RV and there is no manual on that. Doug
  • path1's avatar
    path1
    Explorer
    Feb 01, 2018
    rhagfo wrote:
    Are your slides in and covering air registers??? That could also cause poor air flow
    And over heating.


    First thing I checked. There was a box partly in front of the intake vent. I was hoping that was the problem, but no change.

    Many years ago I tossed a throw rug over one in our old rig and had problems. Hate to admit it but, I felt sort of stupid after finding out that was the problem.

    Thanks for comment. (And keep your Dodge going:) in process right now of putting in fuel pressure gauge, or better stated, trying to remember how dash goes back together)
  • path1's avatar
    path1
    Explorer
    Jan 31, 2018
    dougrainer wrote:
    1. You probably have the SF FQ series which requires COMPLETE removal for any troubleshooting or repair on the work Bench.
    2. IF it heats for that 8 minutes, then the odds are
    A. Hi Limit switch has tripped and possibly defective
    B. Hi Limit has tripped due to restriction in the output heat ducts causing excess burner heat build up. If the unit has been working in the past, then possible Rodent Nest obstruction in some of the duct hoses/ductwork.
    3. By bench testing, that can rule out hi limit switch. Doug


    Thanks, Guess I'll be reading up on above link even to get the thing out of RV. Hope I don't have to wonder around town gathering fittings to work on this thing on the bench. We'll see.
    Thanks again.
  • path1's avatar
    path1
    Explorer
    Jan 31, 2018
    shastagary wrote:
    try this service and training manual manual otherwise do a google search for "suburban rv furnace manual"


    Thanks, now on my disk top.
  • rhagfo's avatar
    rhagfo
    Explorer III
    Jan 31, 2018
    Are your slides in and covering air registers??? That could also cause poor air flow
    And over heating.
  • dougrainer's avatar
    dougrainer
    Nomad
    Jan 31, 2018
    1. You probably have the SF FQ series which requires COMPLETE removal for any troubleshooting or repair on the work Bench.
    2. IF it heats for that 8 minutes, then the odds are
    A. Hi Limit switch has tripped and possibly defective
    B. Hi Limit has tripped due to restriction in the output heat ducts causing excess burner heat build up. If the unit has been working in the past, then possible Rodent Nest obstruction in some of the duct hoses/ductwork.
    3. By bench testing, that can rule out hi limit switch. Doug
  • shastagary's avatar
    shastagary
    Explorer
    Jan 31, 2018
    try this service and training manual manual otherwise do a google search for "suburban rv furnace manual"
  • path1's avatar
    path1
    Explorer
    Jan 31, 2018
    Thanks for quick come back...
    Just came back in after posting...noticed exhaust sounds like if you were to blow thru the flame of a stove burner. Not a whistling sound but sort of like that. I'm thinking spider web or obstruction. But still can't figure out to get to interior parts to find out what's going on.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,198 PostsLatest Activity: Feb 12, 2025