Can't see your pictures. I'm wondering if this is a modified unit. The bimetal coil makes me think that it used to be a combination heater/vent. One electrical wall switch would turn on a heater coil in the unit and blow warm air into the bathroom. Another electrical wall switch would simply turn on ventilation only. Perhaps someone modified this unit ?
See: http://books.google.com/books?id=guY8ZA33zlsC&pg=PA423&lpg=PA423&dq=bimetal+coil+in+bath+vent&source=bl&ots=v130aGH-Be&sig=8__3Zbl6TpYGM7_uLcPCz60YjW0&hl=en&sa=X&ei=OBYMUeG4LOrCigLYu4CAAw&ved=0CHUQ6AEwCQ#v=onepage&q=bimetal%20coil%20in%20bath%20vent&f=false
(but there are many more styles and models)

Personally, I wouldn't invest any money into it. Instead buying a new one and then venting properly to the outside. I don't know what your location is, but venting into an attic space or even near the soffit vents is a big mistake.

Have you called NuTone ? They are helpful.

Here is a link that might be useful: Diagram of Fan Heater Vent

Thanks audio mixer. The HVAC in the house underwent at least a couple of major revisions, floor furnace, baseboard electric, 3 ph water-chilled cooling and finally gas furnace with integral split system cooling when we bought it. Now, we have mini splits. The electric baseboard is coming out, but since gas got cheap, we might keep the furnace functional for a while.

The bath was carved out of other space at some point and has a wall-mounted electric heater that is probably original to that room so a heater in the ceiling would be a liability. The former owner was an electrician and there is a lot of salvaged stuff around. In this case, it might not have been a salvaged appliance, but got at a low price as an overstock or return. I suspect so since the similar light/fan/heater? in the lav probably only ever had the light working and might have been bought under similar circumstances. They are nice-looking and robust units in good shape after many decades.

I live near the LA Gulf coast so it is hot and HUMID here. I am planning on sealing the attic and insulating the roof deck so venting to the outside eventually will be mandatory even though everything goes to the attic now with no apparent problems.

Thanks for the links. I bet that unit pictured in the book is the one in the lav! The one I've taken apart is laid out a little differently. I might do some head-scratching to see if I can mentally reconstruct how it worked. Note that the diagram unit has two blowers while the description of function in the book notes only one motor.

ionized,
make sure you have a working back draft damper
for your bath vent fan.
I use hardcast #1402 mastic tape to attach the
venting to the back draft damper, and then the
back draft damper to the vent fan.
also...back draft dampers can be installed
the right way..where the damper stay closed
when not in use, and the wrong way, where
damper is open all the time.
about half the time..they are installed wrong!

go ahead & vent it thru the soffits now
so that when you foam insulate the roofline
it is done. take a look at stove venting also.
you'll want that to terminate outside of attic.

glad to see you keeping on with the project.
take care &

best of luck

Thanks for the input, energy.

"...damper...about half the time..they are installed wrong!"

Simply unbelievable!

I need to repost the pics. I don't think I moved them, but.....

Nutone might make a replacement fan for this model.
contact them with model number & serial to see
what help they can offer.

I've found Nutone to be very helpful.

Happy Mardi Gras!!

Thanks, energy. I have just been searching and found that AO Smith 541 is a replacement motor and only ca. $50. (Aint the web wonderful sometimes?) Can't find a model or SN on the unit itself. My only hope might be to look up all the nodel numbers that the JA1C002 motor was used in. That's a couple of dozen, at least.

I'll think about Mardi Gras after we get done with this Stupidbowl interruption. Are there any Courir de Mardi Gras activities where you are or are you too far North for that?

good deal Ionized!

Shoot, I was going to invite myself to your
house for Lundi Gras! Miss the night parades with
the flambeaus!
for Mardi Gras here...they costume and ride horses,
they start on the parade route..in the country and
stop at each house.
the people at the houses contribute
something for the pot of gumbo at the end of the
parade route.
at one of the houses they ..yes I'm serious..
chase a chicken around to put in the gumbo.
that is a trip!
at each house that contributes..the parade captian does
a crazy dance for payment of the contribution.

so you have beer, crazy cajuns...horses, a truck with
a port a let, music and beads. at the end of the
parade when the gumbo is cooking is a big party.

I live in the country and have a parade that
passes in front of my house. they don't chase
the chicken in my yard...but at the guy's house
down the road from me.

the first year I lived here..I had never seen anything
like it.

the costumes aren't as great as say...the costume
contest in the 1/4. no sequins lace or fancy stuff.
mostly they look like pj's with fringe. but the spirit
is there. and the booze. the can man makes a bundle
picking up cans after the parade.

so..want to switch house for Mardi Gras this year??
or next year??

its going to be a blast in N.O. with superbowl then
MG. I miss the wildness sometimes.(but not the traffic)

take care.

Thanks, I've read about Cajun Mardi Gras and seen a lot of pics. I am intrigued by your idea, but I have a counter-offer that might work better. I''ll be in touch by email.

Hi, I decided to go ahead and order the ca. $100 Nutone replacement motor. The original motor is sealed. The $50 motor is open frame. The suspension bracket for the motor would pretty well seal up the end of the motor so it would overheat unless I did some modifications. I might be able to cut some vent slots in it and offset it with some washers, but that would take some time. After studying the specs I discovered that I'd have to trim off the shaft as well.

If I put in a new fan, I'll have to redo the ceiling plaster so it is going to be easier to stick a new motor in the old unit . It IS in great condition and I like the look.

I had a closer look at the similar-looking unit in the lav. It is a heater-light with no vent. There is another vent fan in there mounted near the floor in the wall and exhausts to the crawl space.

I have a Nutone 911ON that is missing the lens. If anyone has one they wish to sell or knows of a source where I can get one please respond