Raypak 406a "Sensor Failure"

[russhull]

Hello TFP community,
I have newer control board (replaced 2 years ago) and am having troubles firing up the pool heater.

I get the error "Sensor Failure" with nothing else to go on.

* It is not a temperature issue as that is reading correctly (replaced about 4 times over 4 years).
* I was running the heater straight for 24-48 hours when the error occurred.
* Rebooted heater multiple times
* checked water flow.
* HI limit 1 and 2 both are good

When turning on the unit it will cycle between
* No demand
* Spark (1 or 2 times)
* Sensor Failure

Any advise is appreciated.

 

[Poolbreh]

The thermistor reads on two fronts. There is a a degree difference of more than 2f on the readings. I would replace thermistor.

 

[1poolman1]

Hello TFP community,
I have newer control board (replaced 2 years ago) and am having troubles firing up the pool heater.

I get the error "Sensor Failure" with nothing else to go on.

* It is not a temperature issue as that is reading correctly (replaced about 4 times over 4 years).
* I was running the heater straight for 24-48 hours when the error occurred.
* Rebooted heater multiple times
* checked water flow.
* HI limit 1 and 2 both are good

When turning on the unit it will cycle between
* No demand
* Spark (1 or 2 times)
* Sensor Failure

Any advise is appreciated.

Sensor failure is virtually always the temperature sensor. If it isn't that, its the board itself (seldom is though). If you are replacing that sensor that frequently, you may want to check your water chemistry.

 

[russhull]

Sensor failure is virtually always the temperature sensor. If it isn't that, its the board itself (seldom is though). If you are replacing that sensor that frequently, you may want to check your water chemistry.

IMO, the temperature sensor failure is due to be buying ripoff cheap versions from Amazon. I don't mind replacing the temp sensor again but feel that the current reading is correct (81 degrees, and 100 felt like 100 in the hot tub)

 

[1poolman1]

As Poolbreh said. This is from the manual. It is two-in-one sensor.