Removing Suburban Furnace

[blawson102]

Have to replace pilot valve assembly on my NI 22A Suburban Furnance in my 70 Airstream. Unit is located under the sink. Can't reach the manual shut-off valve on the side of the heater(not enough room to get your hand in there) or the sensing line for the pilot light assembly. Looks like I have to remove the end of the cabinet to get at the valve and the pilot light sensing line. Anyone know how this furnance is attached and an easy way to remove it without cutting/removing the end of my cabinet.
Thanks

[RUSSELL]

In my 1985 Sov. the unit is under the stove. All I did is take out the 4 screws out side the trailer to disconect it from the wall and the remove the piece of wood laminate in front of the heater. The heather is held by two crews to the floor. The wirening is on a plug that is easy to disconect. The gas was a bear to undo but with flare wrenches is came loose. I also turned of the gas at the tank.
I hope this will help you.
Regards from Russell in sunny Tucson Az.

[A/SimpleLife]

My Suburban furnace in my '71 Ambassador came out from the front, it is under the sink to the left, facing the sink you pull it toward you. The horizontal framing in front of the furnace did have to come out, and I think the screws from the outside, and of course everything else that's attached. Dear old Dad did most of it so that's all the info I have.

Gwen

[overlander63]

Depends on which coach you have, and how it is mounted. Ours was not much fun to remove, and involved taking all kinds of stuff out to get to it, and to remove it.
Also, you need to be aware the NT22 was recalled for a serious safety issue, and should not be used until you have verified the needed repair has been completed.

[Lumatic]

You may not have to remove the cabinet. There is a screw or 2 which secures the base of the guts of the furnace to the bottom of the cabinet. Take these out and disconnect the gas line and the whole kit and caboodle slides out on a track. If I remember you may have to cut a hole in the shelf over the cabinet to undo the latch that holds the front of the cabinet on.

The most IMPORTANT is this furnace is a potential killer. There was a recall on it because the crossover tube deteriorates over time letting carbon monoxide into the coach. Parts are scarce or not available at all and you will be hard pressed to find a RV tech who is willing to work on it. I replaced mine with a NT30 and am glad I did

[Smokin Camel]

Mine came out rather easily. As I recall it had some floor bolts and it slid out from the fromt of the cabinet under the sink. I did have to use angle iron, plywood (with sheet metal over it) to build a stand for the replacement as then newer s20 I replaced it with was much smaller. Get a service manual and it should give basic removal instructions. good idea to get rid of that model. No one would take a chance on a 35 year old furnace in their residence and you are in a smaller space in the AS.

Use the search tool, there are some threads on furnace replacement.

[rmpray]

Mine was allready gone. Living in a bit warmer climate, I included heat strips on my AC. Some say just not enough production from electric heat strips, but enough to knock the occasional chill off as long as you have power.

[Ganglin]

Originally Posted by Lumatic

You may not have to remove the cabinet. There is a screw or 2 which secures the base of the guts of the furnace to the bottom of the cabinet. Take these out and disconnect the gas line and the whole kit and caboodle slides out on a track. If I remember you may have to cut a hole in the shelf over the cabinet to undo the latch that holds the front of the cabinet on.

The most IMPORTANT is this furnace is a potential killer. There was a recall on it because the crossover tube deteriorates over time letting carbon monoxide into the coach. Parts are scarce or not available at all and you will be hard pressed to find a RV tech who is willing to work on it. I replaced mine with a NT30 and am glad I did

Good memory. From the 72 service manual "to gain access to the latch it is necessary to cut approximately a 3" square hole in galley shelf directly above the latch area to allow latch to swing up. (a 3" hole saw could be used it you are careful not to damage the heater)."

[blawson102]

Thanks to everyone for the info. I didn't know it had a recall. Will look at a replacement.

[fotochop]

yes, chuck it. I have mine pulled out and you are welcome to any and all parts, but I don't think it's worth the safety risk.

I think Palomino in Houston will have the best price, they usually do anyway.

good luck

[Lumatic]

There are several old threads on furnace replacement. Most choose to use a Suburban NT30. You can modify the old furnace cabinet base so it serves as a plenum for the NT30. This will let you more easily utilize the existing forced air ductwork.

[aaryno]

Originally Posted by Lumatic

There are several old threads on furnace replacement. Most choose to use a Suburban NT30. You can modify the old furnace cabinet base so it serves as a plenum for the NT30. This will let you more easily utilize the existing forced air ductwork.

Posting on this thread since this is the first one that comes up on google for "remove suburban furnace airstream".

This is from a 1972 Sovereign International. Looks like NT-30.

Steps:

From the outside:

1) With a Phillips screwdriver, remove the vent cover.

2) With a Phillips screwdriver, remove the screws under the vent cover (second set of screws to remove from the outside). This detaches the back of the unit from the interior wall.

Inside (see first two photos):

3) Open doors wide enough for full access to furnace. Our tambour doors require a little extra help to roll that far up. I'm told they will slide better if the tracks are cleaned and oiled but I haven't gotten that far...

4) With a wrench, disconnect gas line (Gas should obviously be off - Others can talk about safe ways to do this but my rig had been empty for a long time so no residual gas to worry about) (green arrow).

5) With wire cutters, safely disconnect electric and cap for storage or later use (Mine was disconnected with no battery, etc, so I just clipped the wires but if you are) (yellow arrow).

6) With a flathead screwdriver, unscrew the flathead screws at the bottom of the front of the front of the Suburban (blue arrow). Now that I'm looking at the photos I can't remember if I removed them all or just the ones at the bottom on either side.

7) Disconnect the clip at the top of the furnace (orange arrow). Others have noted that if there is not a hole in the shelf above the furnace then you will have to cut one to create access for this maneuver. It had been cut previously on mine so I didn't have to, but it was definitely a DIY job. Did AS not think in 1972 that these would need to be serviced?

8) Slide the furnace out of its box.

That's it.

As far as removing the box, that's quite a bit harder because, as far as I can tell, you will have to remove the front baseboard of the cabinet.

These instructions are sub-optimal and more patient folks will perhaps find a better way. See second two photos

1) I removed the the ducts from the plenum to isolate the box frame. This involved:
a) removing the duct cover on the door side of the cabinet exterior.
b) removing the duct segments on either side of the plenum.
Each of the duct segments are held together by a single phillips screw and the seams are covered in duct tape. I removed one section on the right and the one section on the left, just inside the cover (I actually removed all the duct from the rig back to the bathroom since we are not replacing the furnace).
I ended up using a saw to cut the sides of the box down so I could fold the metal and pull it out after I had removed the vents from the plenum on either side.

2) The containment box is attached to the subfloor with 4 Phillips screws (front/back each side). See second photo. To get the the right rear I used a long flexible screwdriver attachment though since I ended up taking out the plumbing I could have done that first and just reached in easily with a straight screwdriver.

3) I cut through the door side of the box, starting at the bottom corner. I was careful to pull the box (now loose in the cabinet because of step 2 above) all the way forward to make sure the saw wouldnt accidentally punch the exterior skin from the inside.

4) Once I had cut one side of the box I was able to fold it enough to squeeze it through the cabinet opening.

fifth photos shows all removed (as well as most of the plumbing)