Background
A friend contacte me to say that their bathroom fan heater was not working as well as it previously did. When they switched it on there was a burning smell and the motor seemed to take a long time to get up to speed. The Heater was purchased in 1996 so my friend felt it was maybe time to fit a new one but wanted to know if it was worth saving. Being keen to continue the 'Reduce, Reuse, Recycle' ethos i said that i would have a look at it and let him know. The appearance of the heater was very good, given its age and it had no signs of rust or damage given the humid environment it has been in for almost thirty years. I decided to salvage the heater and keep it out of the dreaded Recycling yard.
As soon as the junction box on the wall was removed, a serious problem was found. Who ever had installed the heater in 1996 had not correctly prepared the power leads for such a high power device and the plastic terminal block used to make the connections had melted. Click here to see the details of how this problem was fixed.
As soon as the junction box on the wall was removed, a serious problem was found. Who ever had installed the heater in 1996 had not correctly prepared the power leads for such a high power device and the plastic terminal block used to make the connections had melted. Click here to see the details of how this problem was fixed.
![Picture](/uploads/2/1/2/7/21271896/published/20240323-211640.jpg?1717410098)
The first step was to remove the various size screws holding the covers in place.
When these were removed i was surprised to find that there was no internal frame mounting all the components and that when the front and rear metal panels were removed the entire unit 'fell apart'.
This raised a problem in that the heater could not be bench tested with the covers off so diagnosis of faults and reapirs had to be correctly diagnosed and the unit re-assembled before it could be tested.
![Picture](/uploads/2/1/2/7/21271896/published/20240323-211652.jpg?1717410168)
As soon as the covers were taken off it was apparent what was causing the burning smell. The case was filled with dust and fluff as can be seen in this picture.
Behind all the fluff at the bottom of the picture is the AC mains motor that drives the centrigual fan unit.
There was considerable fluff and dust on the heater elements, heater plates and on the individual spars of the centirugal fan blades.
I made sure that the over heating sensors(bimetallic strips) were clean and that all dust, fluff and hair was removed.
Internally the wiring and connectors were all in very good condition with little or no signs of perishing so these did not need to be replaced.
The brass/bronze bearings were examined on the electric drive motor and on the centrigugal fan. The ones on the fan looked very dry at bothe ends so a small amount of thick greas was applied to the bearings and the fan shafts. As soon as this was complete, the fan definately spun more easily and freely as did the motor.
![Picture](/uploads/2/1/2/7/21271896/editor/20240323-212933.jpg?1717410230)
This picture shows the motor and switch end of the heater after all the dust and fluff had been removed using a stiff bristled paint brush and a vacum cleaner.
The motor and fan unit bearings have been greased and rotated by hand to work the grease fully into the bearings.
The plastic side casings showed some signs of yellowing due to age but the plastic was not brittle nor perished.
![Picture](/uploads/2/1/2/7/21271896/editor/20240323-212938.jpg?1717410329)
This picture shows the heater unit, cleaned, lubricated and ready to be re-assembled.
Re-assembly was a little tricky as the front and back metal plates provide the structure to support the internals and until all the screws are in oplace the unit remains somewhat 'floppy'.
I connected the unit to a mains supply and tested it. The casing required a little adjustment to stop the fan hitting the internal air guide plates but it was clear that the motor was spinning much faster and continued running for much longer after the power was removed.
The heater was remounted onto the wall plate and connected back to the supply. A few minutes of testing revealed that all was working well and there was no burning smell from the dust and fluff!
Re-assembly was a little tricky as the front and back metal plates provide the structure to support the internals and until all the screws are in oplace the unit remains somewhat 'floppy'.
I connected the unit to a mains supply and tested it. The casing required a little adjustment to stop the fan hitting the internal air guide plates but it was clear that the motor was spinning much faster and continued running for much longer after the power was removed.
The heater was remounted onto the wall plate and connected back to the supply. A few minutes of testing revealed that all was working well and there was no burning smell from the dust and fluff!