Using AT200CHIM washer sensor

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Jun 3, 2015
Cincinnati Ohio
Initially installed the washer sensor on an uninsulated section of 6" flex liner above wb insert but below the block off plate.
I decided to insulate this short run of liner (about 9") and covered the sensor with the liner insulation (1/2 " foil face) used for the rest of the liner.
The temp readings between before and after differ by about 250-300 degrees. Old cruising temp was about 500-550 degrees and new temp is around 750-850 degrees. I do have surface mounted thermometers on face of the insert (PE Summit) and they read 550-650 degrees when cruising.
Does it make sense to remove the insulation around the sensor or leave it alone. The sensor is rated to 1650 degrees so I don't think it is getting too hot but would appreciate feedback.



Staff member
Nov 18, 2005
South Puget Sound, WA
You can leave it alone. It sounds like the sensor is now acting more like a probe sensor, which is a good thing. Now try getting the flue temps a bit lower by closing down the air sooner and maybe burning thicker splits.


Minister of Fire
Jan 19, 2019
SE North Carolina
I have a pre insulated line with the washer probe. I stuffed the washer as far up under the insulation ext the the inside liner as a could. Probably 4-6” above the stove outlet. Those temps seem high. On cruise my washer temp is 50 degrees above stove top. I have my alarm set at 700. I will probably switch to a probe thermal couple. Washer responds to slow when I turn the stove down and I will choke the fire more often now compared to when I have the washer under a small weight on the stovetop.