I am not sure of the best forum to post this, but HVAC seems to fit best.
I have an old Nutone vent fan/light in one of my bathrooms. It looks to be of good quality and I like the way it looks so I'd like to make it more useful and rehab it. We are not planning to renovate that bathroom beyond some minor repairs. Fortunately, compared to a lot of the rest of the house, the room is in good shape.
We have been in the house for 3 years and have not used the guest bath much so the fan has not been a priority. I am thinking that I have some time to devote now.
The vent in question looks like it was "sealed up" in a couple of places, but the damper at the top operates freely and there is plenty of space for airflow all the way from the grate to the damper. This thing comes apart with two easily-removed pieces. There is what I will call the outer housing, the central assembly and the motor/fan blade assembly.
I have some pictures of it as it looks from below, intact and with the cover off. I have pics and with the central assembly and upper motor/fan blade assemblies removed. There are pictures of the central assembly from the top and side. The blower motor and fan blades sit in the top of the outer housing on a triangular support that, in turn, sits on rubber dampers in the housing. Note that the top of that central assembly seems to be covered over with metallic tape and so does the "duct" that goes to its side. Covering the top of that central assembly does not seal off air flow to the fan and damper. There is still lots of space around the central assembly and the outer housing. I see no purpose to having those areas sealed up.
There is a curious feature that I do not understand at all. There is a bimetal coil that appears to control a damper to the side of the central assembly. You can see it in the "cover off" pic at about 11 o'clock. That would allow air to come in from the side of the central assembly. If you look at the pictures you can see a connector projecting. You can also see a removable piece of sheet metal in the picture of the outer housing that would allow connection to this dampered connection, from the side, if it were opened up.
I have another observation that might add to the puzzle, or might help solve it. There is a second set of connectors on an area where the plug-in cord is connected to the light socket leads. I did not check them out extensively for continuity. Maybe there was a heater option with this thing?
I have several questions:
1) Is it worth it to rehab this thing given that I like the look and it is probably going to be a lot easier than installing a replacement? It appears that a replacement motor is available for ca. $100.
2) What the heck is that bimetal-controlled damper thing supposed to do?
3) Should I remove that metal foil tape on the top for a wider area for air flow to the fan?
4) Was there a heater option with this thing that might have been removed or was not installed? I am not thinking that I will try to implement this, but I am curious.
Note that there is a similarly-styled fixture in a lav but, in contrast to the fixture in question, there is a squirrel-cage blower in there. I have not taken it apart yet, but I suspect that the ventilator has never been used. There is another fan in that room (near the floor venting to the crawl space). I think it was only used for the light.
There is some information on the motor and vent itself. The motor info seems to be useful, but I have not found any use for any of the information on the other parts:
Information on vent/light itself, but no hits with Google:
235 cfm (10"WG)
Thanks for looking!