By Pentair Pool Products
Part # 6290-070
Manufacturer Code 42001-0063S
Dimensions 1.62" L x 0.87" W x 1" D
Hi Limit Switch - 42001-0063S
Pentair master temp 400 heater. The heater shut down and shows "service heater" light on the display panel, after a few minutes the heater would cycle back on, then off again. The LED on the inside heater panel showed "HLS" (High Limit switch). I replaced the "thermal regulator" and that seemed to fix the problem, now the heater shuts down as before and I get the "HLS" LED diagnostic light again. Any ideas, bad high limit switch? The heater is about 8 years old.
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Hi, Stan. Based on the error code, the High Limit Sensor is bad and will need to be replaced. You can also check the wires or the PCB.
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