Six year old Surburan 42K BTU. Replaced computer board once and blower motor 3 times. Noticed last night it seems the high limit switch is acting up. During a normal cycle, burner will ignite on and off several times. Once RV is up to pre-set temp, furnace will NOT come on until I switch thermostat off, then on....so when I got up this AM...it was really chilly. Thank goodness for some cheap electric heaters:))BTW: Had to braze a crack in heat exchanger last time the motor went south.You furnace gurus will probably suggest: buy/install a new one. When its 10 below zero, it runs 24/7...and 12-volt motors can NOT handle that kind of use...right??? THX and have a great Thanksgiving. Johnny...currently in Iowa.

Sorry for your problems...I often wonder why furnaces never seem to act up and break down in the summer time! :S:W:RI asked a wise old sage (yep..older and wiser than even me!) to read your past and add his two bits worth...he has owned a RV Repair Service here in SoCal for many, many years...He said that only a qualified repair guy like himself can check for possible issues that could be caused by low LP gas pressure which can be from a number of factors, including a malfunctioning regulator, clogged or restricted propane lines or low gas levels in the tank. This can ONLY be tested by a qualified service technician.And low voltage can be an issue, which again can only be checked by a certified service technician.Please note that RV Salvage yards carry furnaces removed from RV's that have been "totalled" from wrecked or damaged RV's that are in perfect, undamaged and fully functional shape..for about half of a brand new unit. Ericksons RV Salvage in Coeur d'Alene, Idaho (208) 664-8902 for example. The great part is that RV Salvage yards can do a local or national search for what you need from other Salvage Yards. Good luck and bundle up!

the above post is right on the money. many people think they can fix furnace problems because they are so simple, WRONG! they have complex issues and you just can't start in replacing parts to fix a problem that is more than just that. it could be your regulator by the tanks, which is a $48 part. get it checked out by a someone who knows what he's doing.

Thx to you two: Will have my propane guy check regulator at the tank (which was just filled).Just had one weird thought: Regulator at 500 gallon tank, line to RV into switch over valve, which I think may be another regulator...which should create some pressure problems IF I remember my propane knowledge. Will also call my local furnace expert and ask him IF my thinking is correct OR faulty???Thx again, guys. Happy TG. Johnny in chilly Iowa.

IOWASTROKER wrote:Johnny...currently in Iowa.There's your problem...check your GPS...your RV is too far north. :BSorry, couldn't resist--I was raised in Iowa, so I know how cold it gets...hope you get the furnace fixed quick.

Thx. I needed some humor in my life. I knew there had to be a simple solution: Winter in TX...OR...anywhere where I can ride my trike year round:)))

Suburan furnace? | Good Sam Community

12 Replies

IOWASTROKER
Explorer
Dec 02, 2013
Totally agree with Ex-Tech re: using a cracked heat exchanger after repair...but wife just had surgery, woke up the day after she came home and RV was 43 degrees. R&R furnace, found crack, brazed and had heat in an hour. Truly think I have found the original cause. Poor airflow. Absolutely the worse furnace set up I have ever seen. Forest River is NOT with the program. Currently NOT using the in-floor system. Right off the front of furnace: 114 degrees and RV is the warmest it has ever been. Single digits most nights lately. Infrared heater in master BR and bath:)))))
Ex-Tech
Explorer
Nov 30, 2013
Brazed the heat exchanger? Please be sure you have a good, working CO detector.

After spending more than 20 years in the wholesale heating and air-conditioning business, I can say with some level of authority that a heat exchanger is NEVER a part that should ever be repaired especially when it has cracked.
dougford
Explorer
Nov 21, 2013
IOWASTROKER wrote:
Thx. I needed some humor in my life. I knew there had to be a simple solution: Winter in TX...OR...anywhere where I can ride my trike year round:)))

We'll be riding our dirt bikes next week. I will of course send pictures to my little brother who is in Iowa...I can be evil like that everyonce in while. :D
It appears as though you're trracking down the problem...at 23 degrees, you gotta get 'er fixed fast!!
nayther
Explorer
Nov 19, 2013
IOWASTROKER wrote:
lAST set of brushes in the motor got so hot, they were melted to the armature. I have read about adding another duct. Did put heat to my water manifold bay off main trunk, but I surely can add another. Plan to replace the dual stage regulator this AM, then move to the big propane tank and replace that one also. THX ...again everybody. Have a great TG. Johnny in chilly Iowa 23 degrees currently.

If the motor got that hot, and your heat exchanger cracked I would suspect an airflow issue. Does it cycle on the high limit when it works? How hot is the supply air at the registers? Easiest thing to do is put a thermometer in a supply and watch what it does, that's how I found out my airflow was too low, it cycled on the high limit and never warmed up the trailer. I added another supply grille/duct and fixed the issue.
IOWASTROKER
Explorer
Nov 19, 2013
lAST set of brushes in the motor got so hot, they were melted to the armature. I have read about adding another duct. Did put heat to my water manifold bay off main trunk, but I surely can add another. Plan to replace the dual stage regulator this AM, then move to the big propane tank and replace that one also. THX ...again everybody. Have a great TG. Johnny in chilly Iowa 23 degrees currently.
time2roll
Nomad
Nov 19, 2013
With a cracked heat exchanger I would suspect poor air flow causing overheat conditions. That high limit switch has probably just gone out from over use cycling the burner when it should have the burner remain on until the wall thermostat is satisfied. When you replace the furnace be sure you are checking all ducting for obstructions. Consider adding an additional duct.

12v motor is continuous duty, no worries. With better hot air flow the duty cycle will be reduced.

I would look at two stage furnace if spending money.
invstr55
Explorer
Nov 19, 2013
IOWASTROKER wrote:
Thx. I needed some humor in my life. I knew there had to be a simple solution: Winter in TX...OR...anywhere where I can ride my trike year round:)))

I think you found the correct answer…we are now located in texas
IOWASTROKER
Explorer
Nov 18, 2013
Thx. I needed some humor in my life. I knew there had to be a simple solution: Winter in TX...OR...anywhere where I can ride my trike year round:)))
dougford
Explorer
Nov 18, 2013
IOWASTROKER wrote:
Johnny...currently in Iowa.

There's your problem...check your GPS...your RV is too far north. :B

Sorry, couldn't resist--I was raised in Iowa, so I know how cold it gets...hope you get the furnace fixed quick.
IOWASTROKER
Explorer
Nov 18, 2013
Thx to you two: Will have my propane guy check regulator at the tank (which was just filled).

Just had one weird thought: Regulator at 500 gallon tank, line to RV into switch over valve, which I think may be another regulator...which should create some pressure problems IF I remember my propane knowledge. Will also call my local furnace expert and ask him IF my thinking is correct OR faulty???

Thx again, guys. Happy TG. Johnny in chilly Iowa.

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Suburan furnace?

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