GE 7 cu ft electric dryer

[the7]

combo52 says:
"Only GE and Frigidare still put the heaters so close to the clothes load and as a result they have to use very sensitive thromostats to prevent the above mentioned problems with clothing damage and fires.

Even European dryers separate the heater element from the clothes by placing it in a metal box away from the drum."

I would think your observations are right.
1) GE should put the electrical heating elements inside a metal box similar to the heating chamber of its gas version.
2)It is also preferable to have a control inlet thermostat in addition to the safety over-temperature thermostat at the inlet such the inlet air temperature could be maintained at an optimal temperature even before the outlet temperature reaches the outlet set-temperature.
3) I think that the newer version of the 29" WP has such control inlet thermostat for the model with Normal/PP/Delicate selection.

 

[the7]

combo52 says:
"On a full sized WP built electric dryer the heater will not cycle even once until the exhaust or blower housing thermostat is satisfied."

Most 29" WP uses "High-limit Thermostat of 250 deg F and Thermal Fuse of 360 deg F" at the inlet. The high-limit may not have a chance to cut-off the heating power because the inlet air temperature does not reach 250 deg during the heating up . The "Thermal Fuse of 360 deg" is for extra safety cut-off and non-settable.

The GE uses two thermostats at the inlet - Safety Thermostat and Control Inlet Thermostat.
I would think that
a) the Safety Thermostat would work at a temperature close to the "High-limit Thermostat of 250 deg F" and
b) the Control Inlet Thermostat would work at a temperature lower than that of the Safety Thermostat (say 20 to 50 deg lower). It is designed to maintain a regulated inlet air temperature. It has two inlet set-temperatures for this model with Normal/PP/Delicate. With a lower inlet temperature, it would take a longer time to reach the target temperature at the outlet.

I think that there are also two inlet set-temperatures in some new 29" WP dryer model with Normal/PP/Delicate(Gentle Breeze model?).

 

[the7]

Looking at the data from the GE circuit diagram:

a) The inlet temperature of the GE is maintained from 180F to 210F by the Control Inlet Thermostat and the Safety Left Thermostat
b) The Thermo Hi-Limit Right Thermostat will shut down the whole dryer if the inlet temperature exceeds 250F when all the other thermostats fail to work.

Thus it seems that the GE dryer is working at a lower inlet temperature than the 29" WP dryer. This could be the reason why the WP does not cycle the heater until the target temperature at the drum outlet is reached.

 

[combo52]

WP 29" & 27" ELECTRIC DRYERS

Most WP 29" and all 27" dryers do not tapper the inlet heat entering the drum, however some electronically controlled 29" dryers have dual heaters and some also have a thermistor on the heater box that controls the inlet temperature for  low temperature loads and to save a small amount of energy on certain control settings.

 

The inlet temperature can be far higher on a WP or other stationary bulk head dryers because the clothing is never in constant contact with the inlet area. The clothing is always quickly passing the inlet. On revolving back dryer drums, including the European models with a separate box the entire rear of the drum can get very hot. This is more likely to happen when the load is very large, the exhaust is too long or otherwise restricted or when very linty items are being dried and the filter clogs during the cycle.

 

[the7]

Thanks combo52 for the valuable info from your experience.

 

[the7]

Further findings for the GE dryer:

a) NORMAL Temperature:
The temperature at the drum outlet varies from 133F to 154F when the target temperature is reached.
The Control Inlet temperature would be maintained within a limit (say 180F to 210F)

b) PPress Temperature:
The temperature at the drum outlet is same as that of the NORMAL.
However the Control Inlet temperature limit will be lower than that of the NORMAL (say could be 10 to 20F lower).

c) Delicate Temperature:
The temperature at the drum outlet varies from 122F to 147F when the target temperature is reached.
The Control Inlet temperature limit is same as that of the PPress.

I will use the PPress Temperature most of time because the clothing seems to be softer with a lower inlet temperature .

 

[the7]

I used the PPress Temp to dry a load of cotton/mixed this morning. It took about 3 to 5% longer to reach the target temperature at the drum outlet. It seems that the dryness and condition of the clothing is quite similar to that using the NORMAL Temp.

I think that there is practically no difference in energy usage. Perhaps it is better for the clothing (especially for Cotton/PP mixed load) using lower inlet heating temperature.