Nutone 9840 Wall Heater

http://www.nutone.com/products/product/21badbef-4e30-45fc-995d-c07b1e80d3b5

Customer service its electrical --thermostat

The problem is most likely the over heating sensor thermostat located directly under the heating elements - The reason the over-heat safety thermostat sensor is tripping the warning buzzer is because either the cool air fan intake is obstructed with dust / dirt, or the fan motor stopped rotating, or the over-heating condition thermostat is defective, or over sensitive - Usually when the cool air intake is obstructed for any reason, the heating elements will glow brighter, and hotter without good air flow, and the elements may start to bow downwards closer to the over-heating safety thermostat - However, if the safety thermostat is defective, it can trigger the warning buzzer even though there may not be an over-heating condition / event present - The buzzer warning going off prematurely also occurred with my Holmes space heater - I checked the air flow first, and then the appliance tip-over switch second - Both were found functioning properly - It wasn't until I replaced the safety over-heating thermostat, did the buzzer stop going off moments after I plugged the space heater in an outlet.

The cycling thermostat must also be replaced when replacing the thermal fuse. The cycling thermostat's failure to cycle off the heating element results in overheating of the dryer which consequently blows the thermal fuse open.




Replacing only the thermal fuse should the dryer stops running and fails to start will result in its premature blowing or even the thermal cut-out (cut-off) located on the heater duct. Like the cycling thermostat, the high-limit thermostat must also be replaced once the thermal cut-out blows open. Refer to the parts diagram in the link below and look for item numbers 31(thermal cut-off), 34(hi-limit thermostat), 39(thermal fuse), and 41(cycling thermostat.

Kenmore Series 70 Electric Dryer (110.74722400) Bulkhead Parts

The problem may lie in where the wall thermostat is placed. If it's too close to the heater, the heater is shutting off prematurely. However, I'm assuming the plot stays lit after the burner turns off.

The Thermostat should not be in the path of a warm air discharge from the furnace, a lamp, TV set, etc.

If the installer did not leave you the Owners Manual, here's a link to it, in a pdf format that you can print and have for future reference. http://www.wfc-fc.com/pdf/Monterey_Top_Vent_IOM.pdf

Please let me know how it worked out for you.

Rich

I would change the Thermostat. if that doesn't fix it? I would buy a Radiator flush and follow the directions exactly you will be surprised how much junk comes out. That should fix all your heat problems.

contact nutone. the problem is that the sensor that shuts off the unit to prevent overheating is too sensitive or faulty. nutone website seems geared towards selling their product so you may have to call them direct at 1-888-336-6157. this is customer support. good luck.6-6157

You should probably replace the heater motor. All the parts should still be available for you fan and it should only take a few minutes to change out.

It's a known problem. I bought my vx550 last year in July and it stopped working this year in May. On for 5 minutes, shut down, can't run for a few hours, runs for another five minutes, etc. I called the Nutone customer service department and they exchanged the unit for a new one, cross shipped, via UPS. Mine was still under warranty though. It has to do with some defective thermostat or controller in the electronics of the vacuum.

Good luck

most fan forced wall heaters do not move a lot of air. check the cfm rating on the heater. the fan sucks in air from the bottom and forces it up to the top where the element is. broan and nutone have good air flow.