Help with Jandy JXI Heater High Water Temp Fault

[Teduardo02]

My Jandy JXI gas heater wont fire up because it thinks the water temperature is too high. I ordered a replacement water temp sensor online and just replaced it but it still thinks the temp is 142 F. I tested the new sensor with a multimeter checking the ohms and it reads properly. Where should I go from here? Thanks to everyone in advance.

 

[Poolbreh]

Pics of the equipment? Sounds like heat is backing up in the intake side of the manifold. Does the heater have a versa flow? And the 1.5 Pentair pump is single speed?

 

[Teduardo02]

Pics of the equipment? Sounds like heat is backing up in the intake side of the manifold. Does the heater have a versa flow? And the 1.5 Pentair pump is single speed?

Here are some pics. I think its a single speed pump and not sure about the versa flow. Sorry I just bought the house and still trying to getting to know how everything works. Thanks

 

[Poolbreh]

(Edit)scratch that, was thinking the heater fired

 

[Poolbreh]

I wonder if the 10k resistor test would work on the jxi. Let’s ask Allen @ajw22

 

[ajw22]

I wonder if the 10k resistor test would work on the jxi. Let’s ask Allen @ajw22

It would but he said he tested the thermistor with a multimeter and it had the expected reading.

There is a thermal regulator and bypass valve in the header that I would check. See page 12 in Workbook JXi Pool&Spa Heater that is a training manual for pool repairmen.

 

[Poolbreh]

I actually said the same thing before I edited it above. The heater never initially fired so his reading 147. The resistor test would rule out board/thermistor.

 

[ajw22]

I actually said the same thing before I edited it above. The heater never initially fired so his reading 147. The resistor test would rule out board/thermistor.

I thought the heater ran like you did.

Connecting a 10K resistor in place of the thermistor will determine if it is the problem is in the wireing or board which it sounds like it is...

 

[Teduardo02]

I'll test with a 10k resistor tomorrow. So if the 10k resistor shows 77 F then the wiring/sensor I replaced is bad? Or if the temp is still super high then the problem is with the board? Thank you both!

 

[Poolbreh]

Correct

 

[harrjd]

@Teduardo02 Same issue did you end up replacing the whole board or did a new thermistor 10k fix the issue?