My Life with Henri (or, Taming the '74 Sovereign)

[Aage]

Originally Posted by Splitrock

Mine was about 2" too short.


I added 2x4's and 1/2" plywood. Outside vent lined up perfect.

Wow, you took off the entire sink, cabinet, etc. Mrs A is not too favourable towards that since things can take a while to get back together and she has Big Plans for company.

But I think I see why you needed the extra height: you took out the original plenum (or your model didn't come with it). I am also trying to avoid that in order to keep the original square metal vents, one of which goes to the rear bath and the other to the main sitting area. Plus, there is another smaller round one for the tanks.

Originally Posted by DKB_SATX

Comparing the size of my old NT22 and the new NT20S, I have no interest in trying to re-use the existing case. The NT20S is roughly the same length as the old furnace, but much smaller in cross section. I think the NT30 has shrunk compared to its ancestor as well, but don't have the same first-hand knowledge of that. If Splitrock's photo is of an NT30, it looks like it's just slightly smaller than my NT22 CO machine (and much larger than the NT20S) which might make re-using the original case more difficult, since you'd have less room for modifications.

Perhaps this summer when it's too hot for pleasant camping in Texas and we've no time to get to the mountains, I'll take apart the galley cabinetry and do the switch. I already bought the new furnace, after all. Hot weather isn't motivational for working on the heating appliance, however.

Well, I found references in other posts from members that DID use the old case with the new furnace. In fact, Bulletin 16 from AS describes doing just that. It seems that many of the BTU output sizes of furnace were (are?) similar or identical sizes.

Originally Posted by idroba

On the original furnace, as I recall, the guts did slide on a track inside the metal case. That has not been a feature of Suburban furnaces for many years.

I would not consider trying to keep the original case if you get a new furnace (and you should). Over the years there have been many little changes in venting for the circuit board (which the old furnaces did not have), electrical connections, gas inlet locations etc. You may even find the inlet and outlet holes to the outside in slightly different loacations (usually lower than original) and have to build a small platform or shim the new furnace up to meet the old hole locations.

If you are not familiar with gas hookups and flair fittings, I would agree that having a professional do that is a good idea.

The hardest thing about furnace change out can be what DKB_SATX has run into, the location inside the cabinet and how to get the damn thing out to begin with. That can be a really tough problem in some AS products of the 70's. *(makes note to self, never get a 1975, 24' Argosy which needs a new furnace)

Your last paragraph is my biggest problem, too. It looks like it's going to be one Heck of a job getting the old furnace out, with or without the shroud (case). I do have a brand new furnace, and you brought up some good things to look out for in terms of watching the venting, but I still think the best path will be trying o recover the old case in order to keep the plenum.

I'll find out once I have the whole shebang apart, I guess.

Thanks to you all for the helpful details and remarks. Much appreciated!

[Splitrock]

Originally Posted by Aage

Wow, you took off the entire sink, cabinet, etc. Mrs A is not too favourable towards that since things can take a while to get back together and she has Big Plans for company.

But I think I see why you needed the extra height: you took out the original plenum (or your model didn't come with it). I am also trying to avoid that in order to keep the original square metal vents, one of which goes to the rear bath and the other to the main sitting area. Plus, there is another smaller round one for the tanks.

My new furnace is a NT30. I removed almost everything. I didn't reuse the OEM ductwork. I used the original 4x2 into eight inch box and replaced everything else with new. The cabinets were poorly made, lacked counter working space, and lacked drawer storage.

I replaced all the cabinets, counter tops, sink, cooking stove, and refrigerator at the same time I replaced the furnace and water heater. The PO replaced the converter and the tanks, so I'm reusing those.

I have it all back together now except for the bed platform and the two side tables. Those are built, just not installed.

[Steve Bryant]

Aage,
Do you have any pictures that you could post of the space where the old furnace resides and the new furnace? Also, once you pull the old furnace out, you can sit the old and new side by side on a table or workbench and consider what needs to be done. Don't get in a big hurry about doing this and it will probably go faster because you'll figure out a really good approach to the transplant. I'll be following your progress and try to help in any way that I can.

Also, I've called the guys at Suburban in Dayton, TN before and they were helpful about what new models would replace my old one...althougt I didn't buy a new furnace. I would recommend a call to Technical/Customer Support.

Regards,

Steve

[Aage]

Originally Posted by Splitrock

My new furnace is a NT30. I removed almost everything. I didn't reuse the OEM ductwork. I used the original 4x2 into eight inch box and replaced everything else with new. The cabinets were poorly made, lacked counter working space, and lacked drawer storage.

I replaced all the cabinets, counter tops, sink, cooking stove, and refrigerator at the same time I replaced the furnace and water heater. The PO replaced the converter and the tanks, so I'm reusing those.

I have it all back together now except for the bed platform and the two side tables. Those are built, just not installed.

My new furnace is the same model, the NT-30. I do want to use the original ductwork since it does what I want and goes where the heat is needed. I hope I don't have to add another outlet, because other than putting one on the same vertical as the existing one near the exit door, I can't see where I would not lose a door or drawer.

I can't wait to see the new cabinetry you are building, I agree, the kitchen furniture is "less than ideal", shall we say?

[Aage]

Originally Posted by Steve Bryant

Aage,
Do you have any pictures that you could post of the space where the old furnace resides and the new furnace? Also, once you pull the old furnace out, you can sit the old and new side by side on a table or workbench and consider what needs to be done. Don't get in a big hurry about doing this and it will probably go faster because you'll figure out a really good approach to the transplant. I'll be following your progress and try to help in any way that I can.

Also, I've called the guys at Suburban in Dayton, TN before and they were helpful about what new models would replace my old one...althougt I didn't buy a new furnace. I would recommend a call to Technical/Customer Support.

Regards,

Steve

Steve,

I took dozens of shots of the existing furnace, and not one of them shows much, due to the way it is hidden in the cabinet. I will look through them again, but really, until I can get the old furnace out, I won't really know how the new one will go in. I do mean to try and hook it up onto the existing plenum though.

I haven't even taken the new one out of the box it came to me in. I will post photos of the two of them side by side once I do get the old NT-32 out.

Here are a bunch of shots, not sure if the titles will come through:

[Splitrock]

Originally Posted by Aage

I can't wait to see the new cabinetry you are building, . . .

Mostly all done.

Added two drawers on sink side.



Added 4 drawers and a nice counter on refrigerator side. Counter has a work light above, a 120 volt outlet, & wall cabinet storage above.



The closet was shortened from 60" to 42" wide. That extra space is used for a side table and wall cabinet in the sleeping area. The twin beds will be replaced with a full with the head of the bed located on the street side.

My current project is outside polish, then awning fabric replacement.

[Aage]

VERY nice work! Is your furnace under the sink, then?

That looks like a brand new refer you got as well. Must be nice

Is your Sov a rear or mid bath? Looks like you are still working on that area.

[Splitrock]

Originally Posted by Aage

VERY nice work! Is your furnace under the sink, then?

Thanks! The heater is under the cooking range.

Originally Posted by Aage

That looks like a brand new refer you got as well. Must be nice

I replaced the refrigerator in 2010 when I added the FanTastic fans, replaced the air conditioner, water heater, the NT30, and the cooking range. I've never run any of it yet. After I bought it "as is", I was disappointed that nothing associated with this trailer worked. Everything was either broke, ugly, or, like the water heater, not worth the risk associated with the OEM unit.

Originally Posted by Aage

Is your Sov a rear or mid bath? Looks like you are still working on that area.

It's a mid bath. I still have to build a bathroom door, give the vanity a facelift, and reinstall the toilet. So far, I'm not replacing the shower . . . but I might.

I have the bed pedestal, two side tables with matching HPL tops, and a wall storage cabinet made for the rear, just not installed yet. I want to get the outside polishing done so I can reinstall the awning arms and roller. I removed the awning roller to get it straightened. That's been done a year now.

I believe in "seasoning" my big jobs.

[Steve Bryant]

Originally Posted by Aage

Well, SWMBO has told me that the Time Has Come to do the install of the new furnace. Her sister, who owns the trailer next door in the camp where Henri The Sovereign lives, returns from Florida week after next, and thus we will begin to actually use Henri again. It being none to warm here yet, the furnace is likely to get a good workout.

Monday, we go to see Henri and bring him a furnace he can't refuse.

So: another New Adventure. I haven't replaced a furnace before. Have you?

Here is what my 1974 year Service Manual says:


See the part highlighted in yellow? Is that talking about removing the "track" and the tambour door which hides the furnace? "Tract" sounds like something to read in a bus station when you have exhausted everything else.

I don't like the part about cutting the 3"X3" hole, but I can understand why. When I'm there, I will see if there is another way around that, but my jigsaw will accompany us.

And so, dear readers: does anyone have any hints or suggestions as to how to best change out a 38-year-old furnace with a brand-new one?

I look forward to your help, ideas, and interesting stories about how you replaced yours.

I am thinking that this might be a good time to replace the gas pipe to the unit. Now to do that, I think I will get the local LP gas merchant to do for me, since he has all the tools and experience necessary. I seem to remember reading somewhere that, with time, some gooey gunk builds up in the lines. For those who have done this: did any of you you change the supply pipe as well?

The Service Manual stops short of removing the outer case that the heater lives in. I suppose this is because they expect that the existing heater will be repaired and replaced. I doubt that this is possible though; how could I have that much dumb luck that everything will match up given that what I am putting in is thirty-eight years newer than what I am taking out!?

I really do feel fortunate to have access to the depth of information available here. Thanks in advance to anyone that has a pointer or two to pass on to me.

Aage,
The pictures really help! I've re-read your furnace removal instructions and compared them to the pictures and now I have a "picture in my mind" of the configuration of all of this.

First, I don't think that you'll have to do surgery on the shelf at all. That's just a quick and dirty approach to the task at hand...more about this in a minute. Also something to remember is that the furnace removal and instalation process involves just five aspects:
1. Structurally securing the furnace (mounting screws)
2. Electrical wiring - not much will change here other than possibly wire length...positive and negative power wires plus two thermostat wires that go to a switch (opens and closes to turn the furnace on or off as required for temperature regulation)
3. Disconnecting/reconnecting the gas line and checking for leaks - maybe you'll need to replace the copper line and maybe not (depends on where the old versus the new connections are and the condition of the copper line)
4. Heated air ducting - likely the old and new configurations can easily be adapted to Henri
5. External intake and exhaust of combustion air/gas discharge - likely to be the biggest challenge, but maybe not so much...let's wait and see

OK, back to the surgery on your shelf. Shelve that notion for a minute and consider this approach.

I'd remove the upper and lower tambor door tracks and the sliding tambor mechanism first. Then, I'd figure out what I needed to do to remove the shelf above the furnace. It probably just has sheet metal screws around the perimeter. Some of the screws may be a little difficult to reach, but take your time. Once the shelf is removed, you can see the furnace much better and really have access for removal and installation. BTW, once you have turned off the gas valves on both bottles, crack open a burner on the stove for a minute and this will relieve any pressure in the line. Remember to turn off the stove burner so that it isn't open when you turn the gas back on later.

Think of this whole process as an adventure that has a few challenges like any other self-respecting adventure would. When you're finished you'll have pride in the completed job and more confidence in your ability to do projects of this type.

Regards,

Steve

[Aage]

Steve,

Thanks very much for your effort in reading the whole thing, and thinking through what I could do to disassemble the furnace.

I have a couple of problems with what you are suggesting I do, though.

The first one is that the removal of the tambour door on that side appears to require the removal of the lower track. The lower track is held in place by rivets, which are hidden behind covers mabe from what appears to be the same laminate (like Arborite, not mounted on anything) that covers a lot of the dark brown furniture in the TT. I looked and looked and tugged and pried with various tools to see how to get the dang plastic cover off, and no dice. I could just go through it to the screws and/or rivets, but that won't help the décor of the TT much.

Secondly, the shelf is held in place by a bunch of rivets, and I don't have a drill with a right-angle powerhead to get at them. I considered using a sharp chisel to knock their heads off, but I am now back to leaning to making the 3"X3" hole now.

As you might imagine, I am clinging to the hope that I can do this job without removing the countertop and working down to the furnace. That to me is obviously how it was originally installed; bottom up, so top down is the logical way to get at it. That's how Splitrock did his, since he made a completely new and beautiful galley assembly.

However, the DW is dead against making the kitchen unusable for the projected length of time it would take to do all that.

I'm going down there again on Sunday night, and am determined that next week, the furnace goes in, one way or another. Thanks again for your support!

[pgr32e]

I replaced my furnace last year. My installation was almost identical to yours. When I took the old furnace out, I didn't have to drill a 3" hole in the top shelf, Just drilled the rivets on the left side of the shelf support and pried it up a bit enough to get at the latch ( stupid place for it ). Once the latch is undone, the cover off then you will see that the furnace guts sit on the hot air plenum and when the rest of the fastenings are released, the guts should slide out over the lower tambour slide without removing it.
With the new nt30, to match the intake/exhaust ports you will have to raise the furnace about one and a half inches. Even then I ended up putting a doubler on the outside to neaten up the messy ones on the original. I just used 1 1/2" shelving steel to lift it.
You have to be a bit creative with the ducting in the new install, I used part of the old cover after mounting the unit on the deck of the old case. I cut the old case down to the deck and built from there. Also cut the bottom outlet hole larger for better airflow.
Didn't have to replace the gas line but I did shorten it and put in a new valve. The pics are one of the old unit and the other four of the new Hope this is some help.....Phil.

[Aage]

Phil,

This is more super help, and great photos there, they add a lot.

First: sorry to have so many questions, but when I get to the TT, I won’t have any internet access, so I am trying to be sure to cover all my bases.

Do I understand that you pulled the guts out of the old housing and put the guts for the new one in the same cabinet? It actually looks to me like you managed to get the old housing off and use the new one that came with the NT-30. What needed to be done to get the old case off?

Also, you had to move the case up an inch and a half to line up with the existing exhaust and fresh air vents. But you used the existing plenum. How did you cover the gap that lifting up the housing created?

(This might be the same question but in a different way) You need to seal the housing to the plenum, otherwise there won’t be enough air pressure, right? You refer to using "1 1/2" shelving steel", is that how you fastened the housing to the plenum? What is 1 1/2" shelving steel?

When you say "I used part of the old cover after mounting the unit on the deck of the old case", what did you use it for?

By case, I think you mean what they call the "plenum" in the AS Service Manual instructions, the box that the furnace’s housing sits on, to which the steel hot air vents connect and vent into the trailer interior, correct?

"I cut the old case down to the deck and built from there.” Can you describe this a bit more?

"Also cut the bottom outlet hole larger for better airflow." This I get, they talk about this in "Bulletin 16" from Airstream. Somehow, the old opening into the plenum was smaller.

Thanks again! You guys are all great, I am getting to understand more and more of this.

[Steve Bryant]

Phil,
You bring the insight from having been there! One question: what role does the Swiss Army Knife play in this surgery? Does it substitute for the scalpel?

Aage,
I've used a chisel to cut a lot of rivets in my current floor rot/leak endeavor. I don't have a right angle drill either.

[Aage]

ps: Phil, do you happen to have a photo of the old furnace where I can also see the plenum as it sits on it?

[pgr32e]

Ill try and get everything answered here. When you get the working part of the furnace (guts) out you will have a hollow cabinet with two levels. Cut the side walls and top out right down to the slides that held the old guts (upper level). The slides are welded to the top of the air plenum (lower level) and I took them off too. A small air driven right angled high speed grinder with thin cutting wheels works well for the cutting. The 1 1/2" steel angle is just bent steel shelving struts with holes and slots cut in it for adjustable shelving. I got mine at Canadian tire in their bulk metals bin, the stuff's available at Home depot too. One three foot length was all I needed. Any thing that will lift the new furnace to come close to the old holes will do. Once you have the new furnace fitted at the right height, then you have to join the new air outlet to the old plenum. With a few stray pieces of galvanized furnace duct metal and part of the removed cover, some steel pop rivets and a few high heat nuts and bolts, voila, I now have lots of heat and the CO monitor is dormant. Oh yeah, the jack knife was to demonstrate a less than satisfactory weld in the old heat exchanger. That and the corrosion at the lower right was the reason for the job in the first place. Hope this has been helpful, I only wish I had taken more pictures showing the process.....Phil.

[Steve Bryant]

Phil,
You did a great job of answering Aage's question. But I'd still like to know about the role of the Swiss Army Knife!

[Aage]

Originally Posted by Steve Bryant

Phil,
You did a great job of answering Aage's question. But I'd still like to know about the role of the Swiss Army Knife!

You must have missed this part, Steve:
Oh yeah, the jack knife was to demonstrate a less than satisfactory weld in the old heat exchanger.

[Steve Bryant]

Aage,
You're right, I totally missed the jack knife part.

Phil,
My apologies. I scanned your answer and it all seemed fairly technical and I completely missed your explanation. I guess I was looking for something silly like I stabbed it in the heart to put it out of its misery. Sorry, my bad!

Steve

[Steve Bryant]

Aage,
How goes the furnace installation?

[Splitrock]

I was wrong. Mine's under the sink.