Maker Pro
Maker Pro

modified clothing dryer for low heat function?

jon5500

Oct 31, 2020
74
Joined
Oct 31, 2020
Messages
74
Recently inherited some wool clothing, but my dryer, in its current form, is not capable of a low heat setting. I notice that if I disable one of the 120V inputs, there is no heating although it continues to tumble. For the temporary purposes of low heating, would it be possible to wire a variac at this input in order to control the heating coil? Also, if possible, would appreciate knowing what temperature, in F, is considered "low" within the dryer since I'll be able to measure this with thermocouple. Thank you.
 

Bluejets

Oct 5, 2014
6,990
Joined
Oct 5, 2014
Messages
6,990
The temperature is normally taken care of with a thermo disc.
Just insert a lower temperature unit and you should be good to go.

As for the temp level, it is always a good move to consult Google.
First up in a search determined 125 degrees F for low, and 135 for medium/high for cotton etc.
This should already be a part of your control system.
 

Attachments

  • Thermo disc.jpg
    Thermo disc.jpg
    223.7 KB · Views: 5

jon5500

Oct 31, 2020
74
Joined
Oct 31, 2020
Messages
74
Thanks, appreciate this, but I think that makes it more complicated than what I want to do. For one thing, like with many appliances, there is little more than user manuals and parts diagrams online. The model is a Hotpoint NVLR223 and, according to the user manual, there are three different models with slight variations. The original cycling thermostat is a WE4M181. If I switched out for a lower one, with my existing basic controls, I don't think I would get my high heat back which I use for cotton and other safe clothing. Without knowing how it's wired, I would be hesitant to proceed. The idea with the variac keeps it simple and I don't have to disassemble. I just didn't know if that would work. When one of the two fuses blew out a couple of years back and the heat was out, the drum continued to run indefinitely because I think I also lost timer function, so I would have to monitor and check dryness if the variac would work.

I did Google the temps. One site said 85 F, others said 100 and something and then 125 F as you indicated, so will still have to research more.
 

Bluejets

Oct 5, 2014
6,990
Joined
Oct 5, 2014
Messages
6,990
The idea of a variac may well cook your motor too if you're not careful.
 

Externet

Aug 24, 2009
893
Joined
Aug 24, 2009
Messages
893
I would insert a light bulb socket (mounted on back of dryer unit in series with one heating element wiring; and screw-in a light bulb of the convenient wattage to yield the temperature desired. For normal operation, screw-in a lead fuse with edison base.
upload_2020-12-22_15-48-39.jpeg

What happens if you force the dryer to run only on 120V ?
 
Last edited:

Bluejets

Oct 5, 2014
6,990
Joined
Oct 5, 2014
Messages
6,990
screw-in a light bulb of the convenient wattage to yield the temperature desired.

Good luck finding a light bulb that size.
Did you calculate that at all....????
even half heat would require around 1200w bulb.o_O
 

Frankchie

Nov 14, 2017
149
Joined
Nov 14, 2017
Messages
149
Keep in mind the light bulb or variac solution may not really solve the problem. If the temperature sensor doesn't reach the desired temperature it will not turn the heat off. So it just means it takes longer to reach the temperature sensor setting.

Even if those solutions reduce the temperature satisfactorily it's not likely repeatable unless the loads are identical and other factors are not fluctuating (air temp, voltage, moisture content, etc. ).
 

jon5500

Oct 31, 2020
74
Joined
Oct 31, 2020
Messages
74
For safety and other reasons, I decided to abandon this. I was able to find a nice, used, less than 5 year old dryer with every heat function available for less cost than any modifications I could have done to mine. Only hard part was getting it home, but solved that problem. Now I will cross reference the parts in the replacement versus mine and see if there's any I can keep. If not, I may try and sell it for a little something locally, or junk it if not. It is, after all, about 25 years old.

The good news with this replacement is that a service manual is available online too, unlike my prior one. Not a necessity as most often there are simple parts replacements like belts or rollers, but still nice to have for future reference.
 
Top