Pentair Master Temp 400 E05 Error code


New member
Dec 26, 2014
San Diego
When I turn on my heater the fan turns on within 5 sec, burner kicks in after 10 secs then stays on for 25 secs. All the time the temp indicates 56. Tried cycling three times over an hour with same results. Saw other posts, removed SFS (Stack Flu Sensor) cleaned it (nothing on it) and cleaned both male and female leads. cleaned it three times with same results also.
Ran an OHM meter test get 4 ohms.
Any other things I should look at?

Wife is recuperating and would love to get spa running for her. Thanks.


TFP Expert
In The Industry
Jul 6, 2011
Under the top there is the control board. On the back of the board there are LEDs that light up for the error, usually. Check and see which is on and you could find your problem. Most likely, even though you tested it, usually E05 is the stack flu sensor.


New member
Dec 14, 2018
boca raton/FL
I have the same problem. EO5 error. SFS Sensor passed test at 3.5 ohms. I am between what to order to ensure I get it corrected. Not sure how to test Thermal Regulator or where it really is even...