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Topic: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes) (Read 1687 times) previous topic - next topic

Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Another member asked about this modification I did 8 years ago - he is considering doing the same.  Since I put the information together for him I thought I might as well post it as well.  Unfortunately I didn't take any in-process photos.

On my 1991 U300 the original interior stairwell had only two steps to get from the bottom of the door to the floor.  (I don't have a photo of my original steps but I did find one I saved off from an old ad).  That means each step was close to 11 inches high.  Most stairs have a maximum height of 8.5 inches if not less.  Being on the tall side myself I was OK with it with but when Tina slipped one day that forced a decision to make this change.  As far as I know, subsequent model years went to a 3 step design.  It's hard to know exactly what Foretravel was thinking when they had the 2 step design but my guess is they didn't want the stairwell to encroach into the isle way too much or make the steps too short such that it feels like you are walking down a ladder backwards when descending the stairs. The fact that 1992 was the start of wide-bodies for the Unihomes maybe helped them decide to add the extra step but who knows?

I came up with a design where about 3.5" had to be cut out of the floor - not ideal but a compromise between the risks.  If I cut too much floor away there is a risk of falling in the stairwell when walking by.  If I don't cut any distance into the floor the steps could be too short - a slip risk when descending.  This was weighed against not adding a 3rd step at all which is a risk too - as Tina proved.  Since mechanical engineering is my trade, I designed it on a CAD system (Solidworks) along with a drawing.

The stairwell itself (OEM and the redesigned) are made from 3/4" plywood that is glued and screwed (OEM had U nails).  The stairwell is screwed to steel square tubing in the floor and basement surround.  Foretravel used bolts similar to Roloks but they are flat heads.

One thing I struggled with was re-installing the door frame.  Before I started the project the door outer skin was contacting the frame (rubbing the paint off) in the lower left corner.  I wanted to fix this by trying to make the frame mounting surface as flat as possible.  So this means getting the edge of the plywood flat with the sidewalls.  When I would do a test fit the door still seem to be the same.  So then it occurred to me that maybe the door was not 100% flat so I sanded the high areas, tested, sanded too much, glued wood shims in, etc.  I got it better but not as good as I had hoped.  I work on new locomotives and they have the same issue.  The solution is to "float" the door frame in sealer to the body by tightening the fasteners lightly so the door frame is not twisted.  They use polyurethane sealer on locomotives.  My original motorhome door is sealed with butyl tape and that's what I used too when doing this project.

Another thing I noticed during install was that the hinges had worn down so much that I ran out of "up" adjustment in the hinge slots.  I pulled the hinge pins out and inserted a single nylon washer between the leafs to raise it back up.

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier model Unihomes)

Reply #1 –
I had to add a 1-1/2" angle (1/8" thick) under the floor for support.  The top riser has 4 screws into the vertical wall of this angle.  These screws normally went into the floor tubing that is now gone.  The angle on the forward (fuel tank) side has 1-1/2" of one side cut off the angle and the other side is bent over  90 degrees.  This bent over tab has a screw going into the bulkhead wall.

The cable tray in the basement had to be removed and the when reinstalled it has to mount on top of the horizontal leg of the angle.  A small notch is also required around the bolt that secures the angle to the floor on the rear end of the angle.

The OEM 3/4 HP AC compressor was completely remounted to make it lower and fit under the second step.  A second plywood platform is visible to make it easy to remove for repair.  A few condensation loops were made on the output of the compressor before it goes into the water separator which was also added.  It doesn't seem to work any better than before - I still see moisture coming out of the air hose.  I think a tank would work better. 

The compressor is plugged into a digital outlet timer.  This so the compressor does not come on in the middle of the night and wake us up.  The digital vacation timers do not lose their clock setting when power is cut.  I replaced the pressure switch with a programmable digital pressure switch with two separate set points: one for normal (on at 75 psi/off at 90 psi), the other is for tire filling (on at 100psi/off at 110 psi).  There's a toggle switch to select each one with a third "off" option.

Green stuff is Pergo floor mat.  It was left over from a house project and I figured it might be good to absorb noise from the compressor - it doesn't seem to work as well as the old carpet!

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier model Unihomes)

Reply #2 –
One detail is a thin sheet of flashing used on the bottom of the stairwell that is actually exposed to the weather.  The OEM piece was too worn out to reuse.  I used some flashing from Home Depot, painted it black, and had to cut, fold and seal the corners.  The piece has to wrap around the bottom and up to the floor on both sides.

When redoing the flooring in the stairwell I decided to add some LED lights on both sides.
They are turned on with the touch sensor that is used for the overhead light.  I ran a second wire from the sensor (that goes to outside handle) to the hinge for the kitchen counter leaf.  So when you exit, you just touch that hinge and the stairwell light goes on.  Touching the hinge is almost nature (like the outside handle) so it work well and almost automatically.

The siding in the stairwell is "walnut" Pergo.  I purchased the rubber tread and risers from Global Industrial online for about $160. 

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #3 –
Nice job John, looks better than OEM.
I also put the LED lights along the top of steps but in our U 295 I ran them under the slide track (step cover tray) It makes for a nice improvement doesn't it?
Looks like you have the water tank out of coach too ( in one of pics)
JohnH

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #4 –
Nice work John! I notice the coil of copper tubing behind the stairwell that is between the aux compressor and the water separator. Did you add that? if so, how long is the coil. I plan to add a more robust air dryer filter system to the aux air compressor when I add a switch to allow the aux compressor to supply air for tires etc. The instructions suggest placing the dryer/filter unit 30' feet away from the compressor to allow the air to cool and thus do a better job of removing the moisture from the air. The original separator was mounted with the compressor. I have been considering how I might mount it remotely to allow the warm air to cool before entering the  dryer. I have even considered running a loop of tubing out and back to create the distance but haven't settled on my approach yet. Even if it isn't 30', I am sure adding some tubing length would be a good idea. Copper would also allow a fair amount of heat transfer to take place in a shorter distance than possible with plastic brake line...
Don

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #5 –
Quote from: John Haygarth –
...Looks like you have the water tank out of coach too ( in one of pics)...
Yes, in process and taking pictures.  Will post when done.

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #6 –
Quote from: Don & Tys (AKA acousticart) –
Nice work John! I notice the coil of copper tubing behind the stairwell that is between the aux compressor and the water separator. Did you add that? if so, how long is the coil. I plan to add a more robust air dryer filter system to the aux air compressor when I add a switch to allow the aux compressor to supply air for tires etc. The instructions suggest placing the dryer/filter unit 30' feet away from the compressor to allow the air to cool and thus do a better job of removing the moisture from the air. The original separator was mounted with the compressor. I have been considering how I might mount it remotely to allow the warm air to cool before entering the  dryer. I have even considered running a loop of tubing out and back to create the distance but haven't settled on my approach yet. Even if it isn't 30', I am sure adding some tubing length would be a good idea. Copper would also allow a fair amount of heat transfer to take place in a shorter distance than possible with plastic brake line...
Don
Yes, the copper tubing was my attempt to cool the air before the dryer.  Unfortunately it doesn't s seem to work very well.  It must not cool the air enough.  I still see water in the hose which is after the dryer.  We are on exactly the same page in term of thinking:  A dryer installed right after the compressor is useless since the air is hot and condensate hasn't formed yet.  My coach did not have any dryer at all originally.  I was thinking I might try adding a wet tank but a long length of tubing might good and be easier on storage space.  The type of dryer I have vents out the bottom when the compressor is off so the volume of the cooling circuit is vented too - I would have to change that if I used a tank.

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #7 –
Couldn't a straight line finned baseboard heater core be integrated to cool the air? Small, compact, commercially available and relatively inexpensive.

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #8 –
I don't think they are designed for high pressure. But a small a/c condenser would.

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #9 –
Quote from: nitehawk –
Couldn't a straight line finned baseboard heater core be integrated to cool the air? Small, compact, commercially available and relatively inexpensive.
Sure, so one for a hydronic systems.  I didn't think of that at the time but I suppose any liquid to air heat exchanger would work as long as it could handle the pressure and potential water corrosion.

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #10 –
DUH!! Forgot about the high pressure! :-[  :-[

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #11 –
Craneman, do you mean something like this?
Universal AC Condenser 11" X 21" Parallel High Flow A/C O Ring Fitting | eBay
I was thinking that the volume of air flow would be too restricted (internal friction from the multiple small passages?), but with the parallel flow arrangement, perhaps not. Do you have any idea of what pressure these aluminum units typically be rated for? Surely would provide significant cooling capacity, if it could handle the pressure and not be too restrictive.
Don
Edit: If this goes any further off topic, I guess it may be time to start a new thread! Sorry John, I got excited when I saw your copper tubing arrangement...)
Quote from: craneman –
I don't think they are designed for high pressure. But a small a/c condenser would.

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #12 –
They go to over 300 PSI as R-134a high side goes there at times

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #14 –
I was interested in the entry steps thread. Now you all are talking about something that should have been another thread.  ::)

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #15 –
Quote from: mike leary –
I was interested in the entry steps thread. Now you all are talking about something that should have been another thread.  ::)
Yes it needs to be split into it's own thread. But that's way over my head.
 

Re: Converting stairwell from 2 steps to 3 steps (1991 and earlier Unihomes)

Reply #16 –
Quote from: JohnFitz –
I had to add a 1-1/2" angle (1/8" thick) under the floor for support.  The top riser has 4 screws into the vertical wall of this angle.  These screws normally went into the floor tubing that is now gone.  The angle on the forward (fuel tank) side has 1-1/2" of one side cut off the angle and the other side is bent over  90 degrees.  This bent over tab has a screw going into the bulkhead wall.

The cable tray in the basement had to be removed and the when reinstalled it has to mount on top of the horizontal leg of the angle.  A small notch is also required around the bolt that secures the angle to the floor on the rear end of the angle.

The OEM 3/4 HP AC compressor was completely remounted to make it lower and fit under the second step.  A second plywood platform is visible to make it easy to remove for repair.  A few condensation loops were made on the output of the compressor before it goes into the water separator which was also added.  It doesn't seem to work any better than before - I still see moisture coming out of the air hose.  I think a tank would work better. 

The compressor is plugged into a digital outlet timer.  This so the compressor does not come on in the middle of the night and wake us up.  The digital vacation timers do not lose their clock setting when power is cut.  I replaced the pressure switch with a programmable digital pressure switch with two separate set points: one for normal (on at 75 psi/off at 90 psi), the other is for tire filling (on at 100psi/off at 110 psi).  There's a toggle switch to select each one with a third "off" option.

Green stuff is Pergo floor mat.  It was left over from a house project and I figured it might be good to absorb noise from the compressor - it doesn't seem to work as well as the old carpet!


John, seems like I'm following just what you've done..!!  I just ran a switch to the outlet for the little compressor. We also have a freezer on that side so 2 problems solved. But to turn on the compressor you've got to open the  bay door no timer....