Need basic help removing Suburban Furnace

[plyonsMC9]

Greetings busnuts,

Well, I need some basic information on how to remove my Suburban furnace.  It seems to have a problem with its board, so rather than take the bus in, I'd like to just remove the furnace and take it into the shop to have it analyzed.

I've attached a couple of photos to illustrate my furnace installation. 

How do I get this thing out of the bus?  I've removed the electrical cable.  Turned off the propane.  But the two pipes leading to the outside have me stuck.  How do I detach those pipes?  Or, do I need to ?     I don't see any bolts to remove on the outside cover  - also shown below - first picture..

The second picture is a top-down view - two troublesome pipes are off the right hand side.

Thanks folks!

Best Regards, Phil

PS - the symptom the furnace experiences is that it starts properly when so indicated by the thermostat, but the heat only lasts a couple of minutes or so.  Then it just blows air.   Made sure the propane line was unencumbered to the furnace.  All other propane devices work fine.  If I restart the furnace, it may run again for a few minutes before the flame shuts off.  All tubes have been blown clean with compressed air. 

[skihor]

Most just slip into the outside tubes. The box is usually screwed to the floor just inside the front cover.
Just a note about taking it out to go to the shop, Camping World charged me $35 EXTRA Because they had to hook it up to propane.? Possible sail switch in the squirel cage fan area.

Don & Sheila

[Utahclaimjumper]

Phil, removed the screws and the outside cover (with the two exhaust holes) the two tubes telescope into this cover. removed the electrical plug from the side of unit (as seen from top view) most units have a couple of wood screws thru the bottom to secure it. detach propane line and the unit should be removable.  The best control board out there is made by Dinasour electronics>>>Dan

[Nick Badame Refrig/ACC]

Hi Phi,

From what you are telling me, I've elliminated any ignition problems.

My next thought is, Have you somehow blocked the return air?

The symtoms you discribed: heat for a couple min's then cold air, sounds like you are tripping the high limit switch.

Let me know.

Nick-

[Utahclaimjumper]

Phil, second thought, after removing the furnace from the coach, dont be afraid to remove the cover and inspect the sail for freedom of movment. The board is easy to replace and Dinasour has complete instructions. Ive done both of mine and never a problem since.  ( they are very simple)>>>Dan

[Nick Badame Refrig/ACC]

Ahhh,

Found some trouble shooting for ya...


http://www.rvcomfort.com/suburban/service/furnaces_questions.php

Nick-

[Busted Knuckle]

Phil,

I think UCJ has beaton me to the answer, it appears that the cover has 4 "torx"(or simular type)  screws holding it on! I'm try'n to remember what it was but I'm thinking yrs ago my dad had a problem in a S/S unit just like you are describing. If I remember correctly it was a vent pipe or sheild rusted out and as usual instead of just going to a distributor and buying a simple replacement, dad fabricated a new one that would last longer than dirt! LOL!  If all else fails as far as removing the unit goes, theres a company in California that makes a conversion just like yours. I think it's called Moose Creek Motor Cabins, they may be able to assist in how it was installed if ya can't get it out other wise! LOL! Just jok'n I'm sure with a sawzall, a 62" pry bar and a 10# sledge hammer you'll have no problem getting it out! (Putting it back in could be another story though!) LOL BK  

[plyonsMC9]

You guys are terrific! 

Plenty of things for me to try!  I think I should be able to tackle this now - -

I will post the results -

Knuckle - very funny.  How did you know that I normally started my projects with those tools.  Well, I don't start them that way.  After about 5 minutes though....           

Kind Regards, Phil

[plyonsMC9]

Most just slip into the outside tubes. The box is usually screwed to the floor just inside the front cover.
Just a note about taking it out to go to the shop, Camping World charged me $35 EXTRA Because they had to hook it up to propane.? Possible sail switch in the squirel cage fan area.

Don & Sheila

Hi Don & Sheila - thanks for the heads up!  I'm not going to CW for this - Figures they would come up with an extra charge for that. 

Best Regards, Phil

[Busted Knuckle]

You guys are terrific! 

Plenty of things for me to try!  I think I should be able to tackle this now - -

I will post the results -

Knuckle - very funny.  How did you know that I normally started my projects with those tools.  Well, I don't start them that way.  After about 5 minutes though....           

Kind Regards, Phil

Hey yer not the only one! LOL! After the 2nd or 3rd knuckle on the same project I gets down right angry, and what ever I'm working on does come apart one way or the other! LOL!

[plyonsMC9]

Hi Phi,

From what you are telling me, I've elliminated any ignition problems.

My next thought is, Have you somehow blocked the return air?

The symtoms you discribed: heat for a couple min's then cold air, sounds like you are tripping the high limit switch.

Let me know.

Nick-

Hi Nick,

Actually, there isn't really even a return ducting - the return is basically just a large vent cover about 3 inches directly in front of the return.  Unobstructed.  (hop eye didn't miss pel that last wurd)...

Best Reeguards, Phil

[Nick Badame Refrig/ACC]

Phil,

Maybe your supplys have an obstruction?

Or, maybe the high limit is just bad....Hummmm....

If the furnace fires up then, the board may not be the problem. typical of a high limit or a sail switch. [Obstruction]

Nick-

[plyonsMC9]

Hi Nick,

I'm going to get that beast out of there and examine both - hopefully without the tools Knuckle mentioned - e..g ,sledgehammer, ax, gernade, etc.. (ooops, I added a couple other specialty tools)..

Best Regards, Phil

[jjrbus]

Once you have the screws out includng the screw in the outside exhaust port. It is the one in the middle of one of the circles. It takes a bit of force to pull the furnace out. Where the two tubes telescope together tends to bind up. If you can lift funace up a bit and wiggle from side to side, you should have all the screws out and it will help loosen the tubes.
   The burner lighting and shutting off is called "lockout" One of the reasons for this can be the board. So while you have this thing apart buy a new Dinosaur board $100 and save yourself a lot of headaches. Sell the old board onn Ebay.

    www.dinosaurelectronics.com

  Arizona RV sells the board for $100 including shipping

[NJT5047]

Phil, one other thing to look for, if your bus is stored outdoors, is bugs in the unit.   Insects will fly through the exhaust/Inlet combo pipe and screw up the works.  Mice will build nests in the ducts and cause the unit to overtemp and cyle out.  Be sure that your air return has not been built over.  There isn't a dedicated air return....just pull air from beneath the compartment.  Should be a 1' square or equiv open area for return. Maybe under a cabinet? 
Odd things happen on the way to a completed conversion.   They make a small screen set (Camping World) that goes over the exaust/intake pipes.  Good idea to install one.  Keeps spiders and bugs out of the heater.
At the worse, the heaters are not terribly expensive...you be the 'decider" here, but before I spend $200 bucks on repairs, I'd replace it completely.    Camping World will have a decent price with the "Presidents Club" .. 
Another thing, those heaters will cycle the burner on and off.  Have you left it on for a period after the burning goes out?  Does the fan cool down and stop too?
Has the heater ever worked correctly for you?  Are all the outlets open and unblocked?
This is one of those things that Camping World will install for almost nothing.   And they warranty their work.
The exhaust is probably stuck by sealer between the body and the mount flange.  Get some SS fishing leader wire and tie a wooden handle on both ends, and pull the leader wire through the back of the flange between the bus body. I'll cut thru the sealer and won't damage the bus finish. That exhaust pipe has to be pulled out before the heater will come out....as has already been pointed out. 
Good Luck, JR