I have read many posts complaining of cooler hot and warm temperatures in newer basic Whirlpool washer models. As an allergy sufferer who needs hotter wash temps I have reserched the subject and here is the scoop.

New regulations require washing machines to use less energy. The largest energy component is that required to heat the water for hot and warm wash. Consequently machines have been redesigned to consume less hot water. In the old days the basic models used 100% hot through the hot water inlet solenoid for hot wash and 50/50% hot/cold for warm. Your hot, warm, and cold temperatures were soley a function of the incoming cold and hot sources assuming 100%, 50/50%, 100% for cold, warm and hot respectively. Some of the newer high end machines use thermistors and control boards to generate custom temperatures depending on the fabric cycle. ex: warm may be 95F or say 75F depending on the fabric cycle chosen.

Simple models that only use the 2 solenoid water inlet valve have also changed to reduce energy. The ATC-1 valve restricts the hot water at the inlet to be half the flow rate of cold to mechanically reduce warm temperature. ALso a bimetal switch has been added at the output of the valve so that if the hot goes above 110F, the cold solenoid is activated to keep the "hot" output below 110F.

In the ATC-2 valve the hot/cold is set at a 40/60% ratio with a restrictor on the hot side so warm is a little warmer and the hot is restricted to 115F with a bi-metal switch. Additionally a second bi-metal switch is added to add hot as required to cold in order to keep the cool temp selection at a minimum of 70F.

Just turning off the cold input for a hotter hot does not work because the agitate cycle will start after a time out with an incomplete fill cycle. The restricted hot flow is very low.

I have observed with a new high end model that hot is 100% hot on some cycles aand warm is a 50/50 mix on a few fabric cycles but not all.


George