Pentair 400 no temperature reading only 80

[ToddMan]

I have replaced the stack flu sensor several times, I did get the first one to work for a day but now the board isn’t getting a reading and heater shuts down
Starts and heats and then shuts down…
Reading is always 80. Before I replace the board has anyone discovered another cause? I don’t believe the wires are bad as they don’t show damage. Thanks you in advance! Todd

 

[ToddMan]

I have replaced the stack flu sensor several times, I did get the first one to work for a day but now the board isn’t getting a reading and heater shuts down
Starts and heats and then shuts down…
Reading is always 80. Before I replace the board has anyone discovered another cause? I don’t believe the wires are bad as they don’t show damage. Thanks you in advance! Todd

 

[JamesW]

Exhaust Gas Temperature​

While running, press and hold the On button to display the exhaust temperature (Older Models).

The new models use the Menu to get the SFS.

Here is what the normal exhaust temperature should be:

• Below 250 degrees...very low
• 250 to 290 ..................low
• 290 to 350.................acceptable
• 350 to 480 ..................high
• Above 480...................error/shutdown.

Note: HD models can be up to 75 degrees higher. HD models use a cupro nickel exchanger and the efficiency is slightly lower resulting in less heat transfer and more waste heat.

If the exhaust gas temperature is higher then normal then water may be bypassing the heat exchanger through a broken bypass valve.

If you hold down the "pool on" button, it stays on 80, then flashes to 40, then back to 80, then the 80/40 reading and E05 indicate that the board is not getting a reading from the sensor. It's usually a bad sensor or damaged wires.

Pentair MasterTemp Heaters - Further Reading

www.troublefreepool.com

 

[JamesW]

E05 Error with SFS Reading 40​

If the SFS reads 80, then flashes to 40, then back to 80, then the 80/40 reading and E05 indicate that the board is not getting a reading from the sensor.

Try reseating the connectors on the SFS.

Otherwise it's a bad sensor or damaged wires.

If the sensor and wiring are good, the board is probably bad.

Disconnect the sensor and check continuity across its terminals.

Resistance should be 3.5-4.0 megaohms.